10. Force of Surface Tension

2A10.10 sliding wire
2A10.10 sliding wire A soap film provides the force to slide a light wire on a frame.
2A10.10 force on a film A soap film pulls a wire up a frame.
2A10.10 sliding wire A soap film pulls a sliding wire up a U shaped frame.
2A10.10 soap film pullup A soap film pulls a sliding wire up a "U" shaped frame.
2A10.11 sliding wire A sliding wire frame film with a spring on one end and a string pull on the other shows that tension does not increase with length.
2A10.12 sliding wire, etc. The sliding wire, wire cubes, and other soap film stuff is pictured.
2A10.15 submerged float
2A10.15 submerged float When submerged, a wire hoop keeps a float beneath the surface of water due to surface tension.
2A10.15 submerged float Surface tension holds a brass ring on a float beneath the water.
2A10.15 submerged float A cork and lead device floats with a wire ring above the surface. Push the ring below the surface and it remains until soap is added to reduce the surface tension.
2A10.20 floating metals Float needles, paperclips, rings of wire, etc. on water.
2A10.20 floating metals Float needles, paper clips, rings of wire, etc. on water.
2A10.21 floating metal sheet
2A10.21 floating aluminum sheet A sheet of aluminum will float on the surface of clean water.
2A10.21 floating metal sheet Float a sheet of metal on the surface of distilled water and add weights until the metal sinks.
2A10.25 leaky boats
2A10.25 leaky boats Try to float several large (one foot long) flat bottomed boats made of different screen material or aluminum with different size holes.
2A10.25 leaky boats A screen boat, razor blade, or small metal boat with a large hole all float on water.
2A10.25 watertight sieves A mesh boat floats until a drop of water is placed inside it. Dry cheesecloth holds water in an inverted beaker.
2A10.28 waterproof fabric model Paraffin coated pegs serve as large model fibers. Pictures.
2A10.30 surface tension balance
2A10.30 surface tension balance An improved method for measuring surface tension by the direct pull method.
2A10.30 adhesion balance A glass plate on one end of a balance beam is in contact with a water surface.
2A10.31 surface tension of mercury Use a Joly balance to measure the force required to pull a razor blade out of mercury.
2A10.32 pull on the ring Pull a large ring away from the surface of a liquid with a spring sale.
2A10.33 surface tension disc
2A10.33 surface tension disc A flat glass disc on a soft spring is lowered onto the surface of distilled water and the extension upon pulling the disc off the water is noted.
2A10.35 cohesion plates
2A10.35 cohesion plates
2A10.35 cohesion plates Two heavy glass plates stick together when a film of water is between them.
2A10.36 cohesion plates There is a difference in cohesion of dry and wet plate glass.
2A10.37 cohesion plates fallacy If they demonstrate cohesion, why do they fall apart when placed in a bell jar that is evacuated?
2A10.37 adhesion plates Atmospheric pressure holds two plate glass panes together.
2A10.38 cohesion tube A long (2-4 m) tube full of water and sealed at the top will support the water column against gravity.
2A10.40 drop soap on lycopodium powder
2A10.40 surface reaction Some soap is dropped onto a water surface covered with sawdust.
2A10.40 drop soap on lycopodium powder Sprinkle lycopodium powder on the surface of water, then place a drop of liquid soap on the surface.
2A10.45 liquid fracture Directions on making a tube filled with Freon 113 which will completely fill the tube on warming and fracture on cooling or when a weak neutron source is brought near after partial cooling.
2A10.50 bubbles blowing bubbles
2A10.50 bubbles blowing bubbles A "T" tube apparatus allows one to blow two soap bubbles of different diameters, then interconnect them.
2A10.50 analysis of bubbles blowing bubbles The complete analytical solution to the two bubbles problem.
2A10.50 soap bubbles A smaller bubble blows up a larger one when connected by a tube.
2A10.50 bubbles blowing bubbles Blow bubbles of different size on a "T" tube. The smaller one will blow up the larger one.
2A10.50 two soap bubbles The smaller soap film bubble blows up the larger one.
2A10.51 rubber balloons
2A10.51 rubber balloons Do the bubbles with large rubber balloons.
2A10.52 rubber balloons The equation relating the internal pressure to the radius is derived and applied to the problem of the two interconnected unequal balloons.
2A10.55 pressure in a bubble Connect a slant water manometer to a tube supporting a bubble. Vary the size of the bubble and note the change of pressure.
2A10.58 water balloon Make a large water balloon.
2A10.60 surface tension bottle
2A10.60 surface tension bottle
2A10.65 wet mop Surface tension pulls the strands of a small fluffy mop together when wet.
2A10.68 sponge action Water picked up by a wet sponge is greater than that picked up by a dry one.
2A10.69 surface tension Discussion of eight surface tension demonstrations.
2A10.70 water droplets Small water droplets form on a surface not wet by water, droplets bounce off when sprayed on with an atomizer. Water droplets will roll across the surface of an overfull glass of water when projected out of a pipette at a small angle.
2A10.71 rolling drops A drop of alcohol can roll on the surface of an alcohol dish.
2A10.72 tears of wine ??? As 50 proof alcohol evaporates in a watch glass, the remaining liquid forms drops that run down the sides.
2A10.73 Plateau's spherule A method of projecting and strobing drops forming down from a vertical orifice.
2A10.74 bursting water bubble A jet of water directed upward against the apex of a cone will cause the water to flow around and form a bubble. A drop of ether will decrease the surface tension and the bubble will collapse.
2A10.75 mercury bubbles Air is blown into mercury covered by a dilute solution of ammonium chloride. Mercury bubbles rise to the surface and burst.
2A10.76 mercury drops Spray clear mercury into distilled water - no coalescence. Then add a little acid - coalescence.
2A10.80 charge and surface tension
2A10.80 effect of charge on surface tension Dripping rate is much greater from an electrically charged buret.
2A10.81 surface tension with electric field Droplets from a orifice become a steady stream when connected to a Wimshurst generator.
2A10.83 electrostatic breakdown of surface t Droplets shoot out of a pond of carbon tetrachloride on a Van de Graaff generator as electrostatic breakdown of surface tension takes place.
2A10.84 elecrostatic dispersion of water dro Water drops from a pipette at high potential are dispersed into droplets.
2A10.85 changing drop size As the amount of sodium hydroxide is varied in a dilute solution, the size of drops formed by a olive oil jet changes with the variation of surface tension.
2A10.95 temperature effects Olive oil sprayed on hot water forms droplets but on cold water forms a slick.

15. Minumal Surface

2A15.01 soap film recipe A Joy(2.5)/water(8)/glycerine(6.5) recipe.
2A15.10 ring and thread A loop of thread in the middle of a soap film forms a circle when the center is popped.
2A15.10 pop the center A circle will form when the center of a loop in a soap film is popped.
2A15.10 ring and thread A loop of thread forms a circle when popped in the middle of a soap film.
2A15.10 pop the center A loop of thread is attached to wire ring. Dip in soap and pop the center of the loop the form a circle.
2A15.10 minimim energy thread Dip a frame with a loop of thread in soap, then pop the film in the center of the thread.
2A15.11 surface energy Puncture various parts of the film that forms on a wire cube.
2A15.20 soap film minimal surfaces
2A15.20 soap film minimal surfaces
2A15.20 soap film minimal surfaces Wire frames dipped in soap film form minimal surfaces. Pictures.
2A15.20 soap film shapes A pyramid, cube, and triangular prism.
2A15.21 catenoid soap film
2A15.21 catenoid soap film A soap film is established between two concentric rings which are pulled apart.
2A15.21 cylindrical soap film Two rings pulled apart with a soap film form a catenoid.
2A15.21 catenoid soap film Picture of a catenoid. setup, some theory and diagrams.
2A15.21 catenoid soap film Dip two concentric circles of wire in soap and separate them to form a catenoid.
2A15.23 soap films - phase transition model- Use soap films to show phase transitions by changing sizes of variable frameworks.
2A15.25 surface energy A soap film on an inverted funnel ascends.
2A15.30 soap bubbles Blow half bubbles on a glass plate. More.
2A15.42 castor-oil drop A large drop of castor oil is drawn under water where it forms a spherical drop.
2A15.50 size of drops Different size drops form on the ends of different O.D. capillary tubes.

20. Capillary Action

2A20.10 capillary tubes
2A20.10 capillary tubes Two sets of capillary tubes, one filled with water and one filled with mercury.
2A20.10 capillary tubes Sets of capillary tubes with water and mercury are compared.
2A20.10 capillary tubes Sets of capillary tubes of various diameters show capillary rise with water and capillary depression with mercury.
2A20.10 capillary tubes Two sets of capillary tubes.
2A20.10 capillary tubes Fill a set of capillary tubes with water.
2A20.11 depression and rise in capillary "U" tubes with a large and small bore arm are filled with water and mercury and compared.
2A20.12 project capillary tubes An optical setup to project capillary tubes.
2A20.20 surface tension hyperbola
2A20.20 surface tension hyperbola A large meniscus forms between two sheets of glass held at an angle in a pan of water.
2A20.20 capillary hyperbola Two glass plates are clamped on one edge and separated by a wire on the other.
2A20.21 meniscus Project the meniscus of water and mercury at the apex of wedge shaped containers.
2A20.30 drops in tapered tubes A drop on water in a tapered tube moves to the narrow end and a mercury drop moves away from the narrow end.
2A20.35 capillary action
2A20.35 capillary action Touch the end of a small glass surface with a small glass tube and the water is drawn into the tube.
2A20.40 meniscus Add 4-penny finishing nails to a full glass of water until it overflows.
2A20.45 meniscus Objects floating in a vessel cling to the edge until it is over full when they go to the middle.
2A20.50 capillary phenomena Four items: dip your finger in water covered with lycopodium powder, a wet paintbrush in and out of water, pour water down a wet string, pour water in a flexible paper box.

30. Surface Tension Propulsion

2A30.10 surface tension boat propulsion
2A30.10 surface tension boats A crystal of camphor is attached to the back of a small boat.
2A30.11 surface tension boat Pieces of camphor placed on the edges of a light aluminum propeller cause it to spin on the surface of water.
2A30.12 surface tension boat How to use alcohol in a surface tension boat.
2A30.13 surface tension boat Rub a match stick on a cake of soap or attach a piece of camphor and place in water.
2A30.20 surface tension flea Bits of camphor dart around on the surface of water until soap is introduced.
2A30.21 surface tension flea A drop of Duco cement will dart around on the surface of water, two drops will play tag.
2A30.30 mercury heart
2A30.30 mercury amoeba A watch glass containing mercury and a solution of sulfuric acid and potassium dichromate is touched with a nail.
2A30.30 mercury heart A globule of mercury is covered with 10% sulfuric acid with a few crystals of potassium dichromate. Touch the mercury with an iron wire to produce rhythmic pulsation.
2A30.31 mercury amoeba Place a crystal of potassium dichromate near a globule of mercury covered with 10% nitric acid.
2A30.32 mercury heart Cover a globule of mercury with 10% hydrogen peroxide and add 1% sodium bicarbonate. A yellow film appears on the mercury and breaks down regularly.
2A30.35 pulsating air bubble An inverted watch glass traps an air bubble over water. Alcohol is introduced at the edge of the bubble through a bent tube at a rate that causes pulsations.


20. Static Presssure

2B20.10 pressure independent of direction Insert a rotatable thistle tube with a membrane into a beaker of water.
2B20.10 pressure independent of direction A thistle tube covered with a diaphragm and connected to a manometer is lowered into water and oriented in different directions.
2B20.10 pressure independent of direction A rubber membrane covers a thistle tube connected to a manometer. The assembly is inserted into a beaker of water and oriented in various directions.
2B20.10 pressure independent of direction Membrane on a tube connected to a manometer.
2B20.11 pressure independent of direction Three thistle tubes filled with colored alcohol and capped with rubber membranes are joined with the thistle ends bent to be oriented in various directions. Immerse in water to show equal pressure. Or, one tube may be turned to show the same thing.
2B20.15 pressure dependent on depth
2B20.15 pressure dependent on depth fallacy The manometer used in the demonstration is calibrated on the basis of the law under investigation.
2B20.15 pressure dependent on depth Lower a small funnel covered with a rubber membrane attached to a manometer into a water filled vessel.
2B20.15 Pressure vs. depth A pressure sensor is connected to a LED bar graph.
2B20.16 pressure vs. depth in water and alcohol
2B20.16 pressure vs. depth in water and alco The electronic pressure sensor and LED bar graph display are used first in water, then in alcohol.
2B20.17 electronic depth dependence A circuit based on the Motorola MPX100AP pressure sensor displays a pressure depth curve on an XY recorder. An interesting feature is the use of two liquids showing a change of slope at the interface.
2B20.20 dropping plate
2B20.20 dropping plate
2B20.20 dropping plate Pressure holds a glass plate on the bottom of a glass tube inserted into a beaker of water until the pressure is equalized by another fluid poured into the tube.
2B20.20 dropping plate A thin glass plate stays at the bottom of a glass tube immersed in water and water is poured into the tube until the plate drops off.
2B20.20 dropping plate Water pressure holds a plate against the bottom of a glass cylinder in a beaker of water. Pour water into the cylinder until the plate drops off. A variation uses a lead plate.
2B20.25 Pascal's paradox
2B20.25 Pascal's paradox Two identical truncated cones are in equilibrium on a platform balance, one small end down, the other large end down. Replacing the bottoms with rubber diaphragms and supporting only the extended diaphragms on the scale does not give equilibrium.
2B20.26 lateral hydrostatic pressure An inverted funnel with a cork on the stem floats in a beaker of water. When pushed down into a layer of mercury, it stays; but if the stem is immersed, it floats back up.
2B20.27 hydrostatic paradox - vector analysi Use the hydrostatic paradox to introduce vector analysis instead of some electromagnetism example.
2B20.30 weigh a water column
2B20.30 weigh a water column Same as AJP 28(6),557.
2B20.30 weigh water in a tube Suspend a tube from a springscale in a beaker of water and suck water up into the tube. Why does the scale reading increase?
2B20.30 hydrostatic paradox Suspend a tube, open at the bottom, from a spring scale in a beaker of water and partially evacuate the air from the tube.
2B20.32 chicken barometer
2B20.32 chicken barometer
2B20.32 chicken barometer
2B20.34 hydrostatic paradox - truncated cone
2B20.34 hydrostatic paradox A glass plate is held against the large end of a truncated cone when it is placed under water. The plate drops away when placed against the small end.
2B20.35 weigh a barometer A barometer tube is weighed empty and filled with mercury, then inverted in a vat of mercury and weigh again.
2B20.35 weigh a barometer A spring scale, barometer tube, and mercury in a glass tube that can be evacuated.
2B20.40 Pascal's vases Six tubes of various shapes are connected to a common water reservoir.
2B20.40 Pascal's vases A set of tubes of different geometries rising from a common reservoir of water.
2B20.40 Pascal's vases A common reservoir connecting several weirdly shaped tubes.
2B20.40 Pascal's vases Tubes of various shapes rise from a common horizontal tube. When filled with water, the level is the same in each tube.
2B20.40 Pascal's vases Six tubes of various shapes are connected to a common water reservoir.
2B20.40 same level tubes A commercial device.
2B20.42 Pascal's vases A commercial device with a pressure gauge and interchangeable vessel shapes.
2B20.42 Pascal's vases Vessels of various shapes are interchangeable on a base equipped with a pressure gauge.
2B20.43 simplified hydrostatic paradox Replace the sloped side vessels with stepped sides that include only horizontal and vertical components.
2B20.45 water level Two open tubes are connected by a long water filled hose.
2B20.50 Pascal's fountain
2B20.50 Pascal's fountain A piston applies pressure to a round glass flask with small holes drilled at various points.
2B20.50 Pascal's fountain Water squirts out equally in all directions when forced out of a sphere by a tube fitted with a piston.
2B20.51 Pascal's fountain A piston applies pressure to a flask with vertical jets originating at various points on the flask.
2B20.52 Pascal's diaphragms A closed container has several protruding tubes capped with rubber diaphragms. Push on one and the others go out.
2B20.53 squeeze the flask Squeeze a flask capped with a stopper and small bore tube.
2B20.60 hydraulic press
2B20.60 hydraulic press A hydraulic press is used to break a piece of wood.
2B20.60 hydraulic press, etc. Use a large hydraulic press to break a 2x4. Glass models show the action of valves of suction and force pumps.
2B20.60 hydraulic press A hydraulic press with a pressure gauge breaks a board or compresses a large spring.
2B20.60 hydraulic press Break a piece of wood in a hydraulic press. The press has a pressure gauge.
2B20.61 two syringes
2B20.61 two syringes Two syringes of different size are hooked together and passed around the class for students to feel the pressure difference.
2B20.62 hydraulic can crusher
2B20.65 garbage bag blowup
2B20.65 garbage bag blowup
2B20.65 air pressure lift Lift a person supported by two hot water bottles by blowing them with the mouth.
2B20.66 weight on a beach ball
2B20.66 weight on a beach ball Place a 45 lb weight on a circular wood disc on a beach ball and blow up the beach ball per os.
2B20.66 weight on the beach ball Lift a 25 lb weight with your lungs by blowing it up on a beach ball.
2B20.66 incompressibility of liqiuds Pound in a nail with a bottle completely filled with boiled water.
2B20.67 hydraulic balance A 2m vertical glass tube is connected to a hot water bottle. Have students sit on the bottle.
2B20.70 compressibility of water
2B20.70 compressibility of water A piston in a heavy walled glass cylinder is screwed in causing mercury to move in a capillary in a second enclosed container.
2B20.70 compressibility of water A heavy walled glass cylinder filled with water is pressurized mechanically and mercury in the capillary tube of a internal water bottle indicates the compression.
2B20.70 compressibility of water An apparatus to show compressibility of water.
2B20.71 water/air compression
2B20.71 water/air compression A syringe filled with air is compressed when a large weight is placed on it, but a water filled syringe does not compress.
2B20.72 Weinold piezometer Diagram. Complicated and delicate.
2B20.75 near-incompressibility of water Shoot a .22 at a water filled half pint paint can and the cover flies off. ALSO - Hammer a nail with the side of a glass bottle filled with water.
2B20.76 incompressibility of liquids With a hammer, strike the stopper of a large bottle completely filled with water and shatter the bottle.
2B20.80 hovercraft
2B20.80 hovercraft

30. Atmospheric Pressure

2B30.05 lead bar
2B30.05 lead bar A 1"x1" lead bar 35" long weighs 14.7 lbs.
2B30.10 crush the can Boil water in a can and cap. As the vapor pressure is reduced by cooling, the can collapses.
2B30.10 crush the can Boil water in a can and cap. As the vapor pressure is reduced by cooling, the can collapses.
2B30.10 crush the can Boil water in a can and seal it. Or, pump out a can slightly, put it in a vacuum chamber and blow it back up.
2B30.10 crush the can Boil some water in a one gallon can, then stopper and pour water over it. ALSO - evacuate.
2B30.15 crush the soda can
2B30.15 crush the soda can
2B30.15 crush the soda can Heat water in the bottom of an aluminum soft drink can, then invert it over a pan of water.
2B30.15 crush the soda can Boil water in a soda can, invert it over water, and then calculate the thermal efficiency during the collapse.
2B30.20 crush a 55 gal drum
2B30.20 crush a 55 gal drum Boil water in a 55 gal. drum using three LP gas burners. A vacuum gage in the smaller bung hole is optional. The barrel crushes at about a half atmosphere.
2B30.20 barrel crush Boil water in a 55 gal drum, seal, and cool.
2B30.25 crush the can with vacuum pump
2B30.25 crush the can with pump A 1 gallon can is evacuated with a pump. A pop can heated with water and inverted on cold water.
2B30.25 crush the can Pump on a gallon can to collapse it.
2B30.25 crush can with pump A one gallon can is evacuated with a vacuum pump.
2B30.26 blow up the crushed can Take a deep breath and blow up a crushed can.
2B30.30 Magdeburg hemispheres Evacuate Magdeburg hemispheres and try to separate them.
2B30.30 Magdeburg hemispheres A set of Magdeburg hemispheres are evacuated with a pump.
2B30.30 Magdeburg flat plates Pump out flat plates separated by an o ring and hang weights.
2B30.30 Magdeburg hemispheres Separate the hemispheres by placing in a bell jar and evacuating.
2B30.30 Magdeburg hemispheres Evacuate Magdeburg hemispheres and try to separate them.
2B30.30 Magdeburg hemispheres Picture of two Magdeburg hemispheres.
2B30.30 Magdeburg hemispheres An evacuated Magdeburg hemisphere set supports a large stack of weights.
2B30.31 Magdeburg hemispheres Pump out a cylinder at least 5" in diameter and lift a student.
2B30.33 Magdeburg hemisphere swing
2B30.33 Magdeburg hemisphere swing Suck out per os two plexiglass plates with a 7.5" "O" ring in between. Hook to the ceiling, grab onto the bottom plate and swing.
2B30.34 Magdeburg tug-of-war
2B30.35 Magdeburg tug-of-war Evacuate two plexiglass plates with a 12" "O" ring in between and hook a 2" rope to each plate. Have students do the tug of war.
2B30.35 Magdeburg hemispheres A fifteen inch set used in a pull off between a Clydesdale and small 4-wheel drive.
2B30.36 suction cups
2B30.36 suction cups Lift a 6" cube of aluminum with a glass handler's suction cup.
2B30.40 soda straw contest
2B30.40 soda straw contest Ask how far a person can suck. Start with a 3' tube, then try 6', 12', and 18'.
2B30.45 inverted glass A 2 m long Plexiglas tube is used for the inverted glass demo. More on dissolved gasses in liquid and cavitation using the same tube.
2B30.46 card on inverted glass modification Replace the glass by a tube of 50 cm and when half filled, it cannot be inverted. Explanation.
2B30.49 atmospheric pressure demos Four demos: 1) Hollow out a "suction cup" in the bottom of a cork so it will stay stuck at the bottom of a beaker as water is poured in. 2) Lift a heavy object by using rubber suction cups. 3) A smaller test tube is pulled into a larger water filled one as the system is inverted and the water runs out. 4) An aspirator is attached to a glass tube coming out of a sealed bottle of water.
2B30.50 lift a stool
2B30.50 lift a stool Place a square foot of 1/16" rubber on a chair and lift the chair by pulling up on a handle attached to the rubber sheet.
2B30.50 rubber sheet lifting chair Lift a chair by placing a thin sheet of rubber with a handle on the seat and pulling up.
2B30.55 adhesion plates
2B30.60 stick and newspaper
2B30.60 stick and newspaper Hit and break the protruding part of a stick covered with a newspaper.
2B30.60 inertia shingles Break a wood stick protruding from under a paper.
2B30.70 vacuum bazooka
2B30.70 vacuum bazooka Put a rubber ball in a tube, seal the ends, evacuate, and puncture the end with the ball.
2B30.80 pressure due to height Flames burn the same at ends of a tube when horizontal but with different heights when the tube is vertical.

35. Measuring Pressure

2B35.10 mercury barometer
2B35.10 mercury barometer A simple mercury barometer.
2B35.15 barometer in a tall bell jar
2B35.15 barometer in a tall bell jar A tall bell jar containing a mercury barometer is evacuated.
2B35.15 barometer in vacuum Evacuate a bell jar containing a barometer.
2B35.16 balance barometer A very sensitive barometer results when a balance which carries a mercury barometer, in addition to reading the weight of the glass tube, also reads the weight of the mercury column (1671).
2B35.18 low barometric pressure A bell jar with a 10" barometer is evacuated.
2B35.20 pull up a mercury barometer
2B35.20 pull up a mercury barometer Pull a barometer tube up out of a tall reservoir of mercury.
2B35.20 pull up mercury barometer Apparatus Drawings Project No.31: A mercury filled tube apparatus with a reservoir deep enough to immerse the entire tube.
2B35.20 constant height of a barometer A deep vat on mercury allows the height of the tube to be changed.
2B35.20 mercury barometer Pull up a mercury filled tube until the mercury falls away. Also the weigh the barometer demo.
2B35.26 water/gas barometer An accurate, easy to build water/gas barometer of similar size to the usual mercury barometer.
2B35.30 manometer
2B35.30 manometer Simple water and mercury manometers.
2B35.31 overhead projector manometer A horizontal manometer for the overhead projector.
2B35.35 magnifying manometer A mercury manometer that when tipped over backward to an inclined position, has an angle whose sine is 1/10.
2B35.40 aneroid barometer
2B35.40 aneroid barometer A large open aneroid barometer.
2B35.40 aneroid barometer Picture of two aneroid barometers.
2B35.40 aneroid barometer Blow and suck on a chamber containing an aneroid barometer.
2B35.50 plastic Torricelli type barometer A Torricelli type barometer made out of Lucite Diagram.
2B35.60 bourdon gauge An open Bourdon gauge with a large element.

40. Density and Buoyancy

2B40.10 weigh submerged block Lower a 3 Kg block of aluminum suspended from a spring scale into water and note the new weight.
2B40.10 weigh submerged block Suspend a 3 Kg block of aluminum from a spring scale and then lower the block into water and note the new weight.
2B40.11 loss of weight in water An aluminum block on a spring scale is lowered into a beaker of water tared on a platform balance.
2B40.12 reaction balance A beaker of water tared on a balance is displaced when an empty test tube is immersed.
2B40.13 weigh submerged block Immerse a lead block suspended from a counterweighted balance in a beaker of water on a counterweighted platform balance and then transfer a weight to bring the system back into equilibrium.
2B40.14 buoyant force
2B40.14 buoyant force A weight suspended from a spring scale is lowered into a beaker of water suspended from a spring scale.
2B40.15 finger in beaker
2B40.15 finger in beaker on balance
2B40.17 improved hydrobalance An improvement of the Nicholson hydrometer.
2B40.17 Nicholson balance A float that allows determination of loss of weight in water very accurately.
2B40.18 board & weights
2B40.18 board & weights float
2B40.18 board and weights float A board sinks equal amounts as equal weights are added.
2B40.20 Archimedes' principle Suspend a pail and weight from a spring scale, lower the weight into water, collect the overflow, pour it into the pail.
2B40.20 Archimedes' principle A mass and bucket of the same volume hang from a spring scale. Lower the mass into water, catch the overflow, and pour the overflow into the bucket.
2B40.20 Archimedes' principle A cylinder and bucket of the same volume hang from a scale. Immerse the cylinder in water, catch the runoff, pour it back into the bucket.
2B40.20 Archimedes' principle Hang a cylinder turned to fit closely inside a bucket from the bottom of the bucket while suspended from the bottom of a balance. Immerse the cylinder in water and then pour water into the bucket.
2B40.20 Archimedes' principle The four step Archimedes' principle with a close fitting cylinder and bucket.
2B40.20 Archimedes' principle Suspend a pail and weight from a spring scale, lower the weight into water, collect the overflow, pour it into the pail.
2B40.21 Archimedes' principle A beaker with a spout is tared on a balance. As an object is lowered into the water, the overflow is run into a beaker on the table and the balance remains in equilibrium. Also, the instructor puts a hand into a beaker of water in a tared platform balance.
2B40.22 Archimedes' - historical discussion Archimedes did not experience buoyancy, only how to measure volume.
2B40.22 Archimedes - historical discusson Volume uncertainties make it impossible to show adulteration.
2B40.22 Archimedes' original experiment Letter that cautions against misunderstanding Archimedes' crown solution.
2B40.25 battleship in a bathtub
2B40.25 float a battleship in a cup of water A small amount of water floats a wood block shaped to just fit in a graduate.
2B40.25 float a battleship in a cup of water A juice can with ballast floats in a 1000 ml graduate. Also - sink the can and look at the water level.
2B40.25 float a battleship in a cup of water Float a 2500 g can in 500 g water.
2B40.25 battleship in bathtub A block of wood is floated in rectangular container.
2B40.26 ship empty and full Add mass to an empty model boat and show pictures of a ship empty and full.
2B40.26 battleship in a bathtub Same as TPT 28(7),510.
2B40.26 battleship in a bathtub Will a cup three quarters full float in a cup one quarter full?
2B40.27 ship pictures full & empty
2B40.30 Cartesian diver Push on a diaphram at the top of a large graduate or squeeze a stoppered whisky flask to make the diver sink.
2B40.30 Cartesian diver A whiskey bottle version and a large bottle with a rubber bulb version of the Cartesian diver.
2B40.30 cartesian diver "tricks" Try a sharp blow on the countertop, prepare the diver with water warmer than room temp and allow it to cool during the class, set the diver so it will remain on the bottom after squeezing.
2B40.30 Cartesian diver Squeeze the flat sides to sink the diver, squeeze the narrow sides to raise the diver.
2B40.30 Cartesian diver - toys A review of two Cartesian diver toys.
2B40.30 Cartesian diver Push on a diaphragm at the top of a large graduate or squeeze a stoppered whisky flask to make the diver sink.
2B40.30 Cartesian diver An inverted test tube diver in a jar.
2B40.30 Cartesian diver A small vial Cartesian diver submerged by squeezing the bottle.
2B40.30 Cartesian diver A buoyant bottle in a water column.
2B40.31 double cartesian diver
2B40.33 Cartesian diver The picture is unclear, but the diver is in a graduate.
2B40.34 Cartesian matches Insert matches with the head down.
2B40.35 hydrometers
2B40.37 buoyant force model A Plexiglas container of agitated plastic spheres forms a "fluid" in which various objects sink or float.
2B40.40 buoyancy of air
2B40.40 buoyancy of air A brass weight counterbalanced by a aluminum sphere filled with air is placed in a bell jar.
2B40.40 buoyancy of air A balance with a brass weight and a hollow sphere is placed in a bell jar and evacuated.
2B40.40 buoyancy of air A toilet tank float is balanced against brass weights in air and in a vacuum.
2B40.40 buoyancy of air A glass ball is balanced with a brass weight in a bell jar and then the air is pumped out.
2B40.40 buoyancy of air The Leybold buoyancy of air apparatus.
2B40.42 buoyancy balloon
2B40.42 buoyancy balloon Place a balloon with some powered dry ice on a balance. Tare, and watch as the balloon expands.
2B40.42 buoyancy balloon Fill a balloon with dry ice, seal it, place it on a scale, and watch the weight decrease as the balloon inflates. Also determine the volume by immersion.
2B40.43 helium balloon in a glass jar
2B40.43 helium balloon in glass jar A helium balloon floats in an inverted container but sinks when the container is filled with helium.
2B40.44 helium balloon in liquid nitrogen
2B40.44 helium balloon in liquid nitrogen Cool a helium balloon to decrease its volume and it will no longer float.
2B40.45 weight of air
2B40.45 weight of air
2B40.45 weight of air in a tire A inflated tire is suspended from a heavy duty spring and the air is let out.
2B40.45 weight of air Place a large evacuated glass flask on a balance, then let air in and note the increased weight.
2B40.45 density of air A one liter flask is tared on a balance, then pumped out and the loss of weight is about one gram.
2B40.45 weight of air A glass sphere is weighed on a pan balance, then evacuated and weighed again.
2B40.46 density of hot and cold air Heat one of two cans hanging from a balance.
2B40.47 CO2 balloon method density of air Use CO2 from carbonated water to fill a balloon for use in measuring the density of air.
2B40.50 liquid density comparison Put one branch of a "Y" tube in brine and the other in colored water and suck.
2B40.51 specific gravity of fluids Water and an unknown liquid are raised to different heights in vertical tubes by a common low pressure.
2B40.53 water and mercury "U" tube
2B40.53 comparison of fluid densities A "J" tube with mercury in the short side and another fluid in the longer.
2B40.53 water and mercury u-tube Water and mercury rise to different heights in a "J" tube.
2B40.54 buoyancy in various liquids
2B40.54 buoyancy in various liquids Iron, bakelite, and wood are dropped into a column containing mercury, carbon tetrachloride, and water.
2B40.56 floating square bar
2B40.56 floating square bar A long bar floats in one orientation in alcohol and switches to another orientation when water is added.
2B40.59 density ball
2B40.59 buoyancy of hot and cold water A hydrometer is made so it sinks in warm water and floats in cold.
2B40.59 density ball A metal sphere barely floats in cold water and sinks in hot water.
2B40.60 hydrometer
2B40.60 hydrometers A constant weight hydrometer, constant volume hydrometer (Nicholson), and Mohr-Westphal balance are used with liquids of various density.
2B40.60 hydrometer A hydrometer is placed in water, then in alcohol.
2B40.61 different density woods
2B40.61 different density woods Float blocks of balsa, pine, and ironwood in water.
2B40.62 density of wood Place a wood dowel in a graduate.
2B40.65 spherical oil drop Olive oil forms a large spherical drop in a stratified mixture of alcohol and water.
2B40.65 large drop A large drop of water is formed in a mixture of benzene and carbon disulfide. Picture.
2B40.65 equidensity bubbles Blow a soap bubble with air and then gas to give a bubble of the same density as the surrounding air.
2B40.65 equidensity drops A beaker of water has a layer of salt solution on the bottom. Place a drop of mineral oil on top and pipette in some colored salt solution. The drop in an oil sac sinks to the interface.
2B40.65 equidensity drops A globule of oil floats at the interface in a bottle half full of water with alcohol on top.
2B40.65 equidensity drops Aniline forms equidense and immiscible drops when placed in 25 C water. Pour 80 ml in cool water and heat.
2B40.65 equidensity drops Orthotoluidine has the same density as water at 24 C and is immiscible.
2B40.66 kerosene/carbon tet. mixtures Kerosene and carbon tetrachloride can be mixed to give .9 g/cc to 1.6 g/cc densities.
2B40.67 chloroform bubbles Chloroform bubbles formed by heating a layer of chloroform covered by a lot of water move up and down.
2B40.70 lifting power of balloons Fill balloons to the same diameter with different gases and show difference in lifting power.
2B40.71 floating and density A tall tube is filled with several immiscible liquids of various densities. Solid objects are inserted that will float at the various interfaces. ALSO, Drop an egg in a tall jar of water and add a handful of salt.
2B40.72 adding salt Salt is added to a beaker of water to make a density ball float.
2B40.73 kerosene and water Float a test tube in water, kerosene, and a combination.
2B40.74 freon and air Fill a pan with freon and float a balloon on it to show the difference in density with air.
2B40.75 pouring gases Pour sulfuric ether or carbon dioxide into one of two beakers on a platform balance. Shadow projection may be used to make it visible.
2B40.76 gasoline vapors A teaspoon of gas placed at the top on a model staircase with a candle at the bottom.
2B40.80 sticking to the bottom Push a rubber stopper that floats on mercury down and squeeze out the mercury between the dish and the stopper.

60. Siphons, Fountains, Pumps

2B60.10 Hero's fountain
2B60.10 Hero's fountain An arrangement of reservoirs connected by tubes that forces a stream of water above the highest reservoir.
2B60.10 Hero's fountain A clever arrangement that allows water to fountain higher than the reservoir.
2B60.10 Hero's Fountain A variant of Hero's fountain in which water shoots up above the level of the reservoir. Diagram.
2B60.15 fountain in a flask A little water is boiled in a flask, a stopper with a single tube is inserted, the whole thing is inverted into a water reservoir.
2B60.20 siphon
2B60.20 sipon A glass "U" tube demonstrates a siphon.
2B60.20 siphon Start with two beakers half full of water and with a connecting hose full of water. Lift one beaker, then the other.
2B60.23 siphon in a bell jar Water is transferred through a "U" tube from a sealed flask to an open beaker when the assembly is placed in a bell jar and evacuated.
2B60.24 siphons An apparatus that shows atmospheric pressure (not cohesion) to be the basis for the siphon action.
2B60.25 pressure measurement in siphon Hook a manometer to the upper portion of a siphon.
2B60.26 gas siphon Carbon dioxide is siphoned from one beaker to another.
2B60.29 siphons A mechanical model of a siphon consists of chain hung over a pulley to a lower level. A diagram of a intermittent siphon (Tantalus cup) is shown.
2B60.30 self starting siphon An inverted "U" tube sealed in the side of a beaker makes a self starting siphon.
2B60.30 self-starting siphon A diagram of a self-starting siphon.
2B60.35 intermittent siphon A funnel with a "?" tube inside makes a self starting intermittent siphon.
2B60.35 intermittent The picture looks like the intermittent siphon.
2B60.40 Maiotte flask and siphon
2B60.40 Mariotte flask and siphon A Mariotte flask is used to make a siphon with a constant flow rate.
2B60.40 Mariotte flask The height of an open tube inserted through the stopper of a jug with an outlet at the bottom regulates flow.
2B60.60 hydraulic ram
2B60.60 hydraulic ram Same as M-291.
2B60.60 hydraulic ram Analysis of the hydraulic ram with picture of a demonstration device.
2B60.60 hydraulic ram A large quantity of water falling a small height pumps a small quantity of water a large height.
2B60.60 hydraulic ram A diagram of how to construct a demonstration hydraulic ram.
2B60.60 hydraulic ram A glass model of a hydraulic ram that lifts water higher than the supply.
2B60.70 spiral pump A spiral pump made of a glass tube coil.
2B60.75 lift pump
2B60.75 lift pump A glass model of a lift pump.
2B60.80 force pump A glass model of a force pump.
2B60.85 hydraulic lift A glass model of a hydraulic lift.


10. Flow Rate

2C10.10 velocity of efflux
2C10.10 velocity of efflux A tall tube of water has holes top, middle, and bottom. Compare the range of the water streams.
2C10.10 velocity of efflux One page analysis and some teaching hints.
2C10.10 velocity of efflux Small holes are drilled top, bottom, and middle of a cylinder of water.
2C10.10 velocity of efflux A tall reservoir of water with holes at different heights.
2C10.10 velocity of efflux A bottle has horizontal outlets at three heights.
2C10.10 Toricelli's tank Water streams from holes at different heights in a vertical glass tube.
2C10.11 Toricelli's tank Determine the velocity of efflux by the parabolic trajectory method or attach a manometer to the various openings. Holes of different size at the same height show independence of diameter.
2C10.12 Mariotte's flask A flask with three holes drilled in the side at different heights is filled with water and closed with a stopper fitted with an open glass tube. The flow from the holes changes as the tube is moved up and down.
2C10.20 uniform pressure drop
2C10.20 pressure drop along a line Open tubes along a drain pipe show pressure drop along a line.
2C10.20 viscosity A series of small holes in a long 3/4" water pipe shows pressure drop due to friction. Do the same thing with 3/8" gas pipe.
2C10.20 uniform pressure drop Water flows in a horizontal glass tube with three pressure indicating standpipes fitted with wood floats.
2C10.22 viscosity Run a water pipe around the lecture hall with pressure gauges at the top and bottom of each side. Show the difference between static and kinetic pressure.
2C10.26 syringe water velocity
2C10.26 syringe water velocity Squirt water out of a syringe. The water moves faster through the constriction.

20. Bernoulli Force

2C20.05 hydrodynamic attraction Move a small sphere in water and another in close proximity will move due to hydrodynamic attraction. Pictures.
2C20.10 Bernoulli tubes
2C20.10 Bernoulli tubes Air flows through a restricted tube. Manometers show the pressure differences.
2C20.10 Bernoulli tubes Air is blown through a constricted tube and the pressure measured with a manometer.
2C20.10 Bernoulli tubes A series of manometers measures pressure of flowing air at points along a restricted tube.
2C20.10 Bernoulli's principle Three pressure indicating manometers with bright wood floats are located at and on either side of a constriction in a horizontal tube with water flow.
2C20.15 constriction in pipes Open vertical pipes show the drop in pressure as water flows through a constriction.
2C20.15 Bernoulli tubes Vertical tubes show the pressure as water flows along a restricted tube.
2C20.20 atomizer
2C20.20 atomizer A jet of air is blown across one end of a "U" tube.
2C20.21 aspirator, etc. Three demos. 1) Water runs through a 1/2 " dia tube constricted to .1". The dissolved water boils in the constriction. 2) Hook a water faucet aspirator to a mercury manometer. 3) Blow one tube across the end of a second vertical tube dipped in water.
2C20.25 pitot tube
2C20.25 pitot tube A small Pitot tube is constructed from glass.
2C20.25 pitot tube A pitot tube is connected to a water manometer and the air stream velocity is varied. Graphics.
2C20.26 venturi meter A manometer measures the pressure difference between the restricted and unrestricted flow in a tube.
2C20.30 floating ball A ball is suspended in an upward jet of air.
2C20.30 floating ball A ball is suspended in an upward jet of air.
2C20.30 floating ball A ping pong ball is supported on a vertical stream of water, air or steam.
2C20.30 floating ball Float a ball in an air stream.
2C20.30 floating ball in air jet A styrofoam ball is suspended in an air jet from a vacuum cleaner.
2C20.31 floating objects Balls, screwdrivers, etc. float in a jet of air.
2C20.33 oscillating Bernoulli Balls An air jet keeps two balls at the high edge of semicircular tracks.
2C20.35 funnel and ball Support a ping pong ball by air or water streaming out of an upside-down funnel.
2C20.35 ball and funnel Air blowing out an inverted funnel will hold up a ball.
2C20.35 funnel and ball A ball will stick in the apex of a funnel hooked to an air supply.
2C20.35 ball in a funnel A ping pong ball is supported by air or water streaming out of an upside-down funnel.
2C20.36 ball in a stream of water
2C20.36 ball in a stream of water Same as AJP 34(5),445.
2C20.36 ball in a water stream Drill out a clear plexiglass tube to different diameters, connect water, and show that the ball sits at the change of diameter despite being tipped upside down.
2C20.40 lifting plate Air blows radially out between two plates, supporting weights hung from the bottom plate.
2C20.40 lifting plate Air blowing out between two horizontal plates supports a mass.
2C20.40 lifting plate A stream of air flowing radially between two plates will lift the bottom plate.
2C20.40 suspended plate in air jet Air blows radially out between two plates, supporting weights hung from the bottom plate.
2C20.41 lifting plate A pin is stuck through a card and it is inserted into the hole in a wooden spool. Blow in the spool and the card sticks. This can be scaled up if higher air pressure is available.
2C20.41 lifting plate Blow into a spool and lift a paper with a pin stuck through into the hole in the spool.
2C20.43 spin out the air When a disc hanging from a spring scale is mounted just above an identical spinning disc, the spring scale will show an increase in force.
2C20.44 coin in cup
2C20.44 blow coin into cup Place a coin in the table a few inches in front of a coffee cup, give a puff, and the coin jumps into the cup.
2C20.45 attracting sheets
2C20.45 attracting sheets Blow are between two sheets of aluminum.
2C20.45 attracting sheets Blow air between two sheets of paper of two large balls and observe the attraction.
2C20.45 suspended parallel cards Blow an air stream between two parallel cards on bifilar suspensions.
2C20.46 sticking paper flap A stream of air blown between a paper and a surface will cause the paper to cling to the surface.
2C20.50 airplane wing
2C20.50 airplane wing projection A small cross section of an airplane wing with manometers at various locations is built into a projector assembly. A vacuum cleaner provides the air source.
2C20.50 wind tunnel An airplane wing element in a small wind tunnel shows lift.
2C20.50 airplane wing A balanced model airplane shows lift when a stream of air is directed onto it.
2C20.51 airplane wing Hold one edge of a sheet of paper horizontally and let the rest hang. Blow across it and watch the sheet rise.
2C20.52 airplane wing Connect a slant manometer to holes on the top and bottom of an airfoil.
2C20.53 raise the roof Air blown over a model house raises the roof. Picture.
2C20.54 paper dirigible A paper loop in an air stream and a falling card.
2C20.54 Rayleigh's disk A lightweight disk turns perpendicular to the air flow.
2C20.55 straight boomerang Make a light straight boomerang from balsa. The theory is different from the usual one.
2C20.55 boomerang flight An article explaining boomerang flight along with directions for throwing and building one.
2C20.56 fly wing mechanism How to build a working model of Pringle's fly wing mechanism.
2C20.57 flying umbrella A motor mounted inside an umbrella is attached to a centrifugal fan mounted above the umbrella pulling air through a hole in the top so it flows down over the side. Develops a few oz of lift.
2C20.58 dropping wing sections A folded index card, a paper pyramid, or a paper cone are stable when dropped apex down.
2C20.59 explaining lift Explain lift based on repulsive forces.
2C20.59 aerodynamic lifting force explained An article explaining that the longer path length does not cause lift.
2C20.59 aerodynamic lifting force Lift is explained as a reaction force of the airstream pushed down by the airfoil. Several demonstrations are shown.
2C20.60 curve ball Use a "V" shaped launcher to throw curve balls.
2C20.60 curve ball A sandpaper covered wood track helps give a ball lots of spin.
2C20.60 curve ball Throw a 3" polystyrene ball with a "V" shaped launcher lined with emery cloth.
2C20.60 curved ball trajectory A ping pong ball is thrown with a sandpaper covered paddle.
2C20.60 curve ball A "V" shaped launcher lined with styrofoam is used to launch curved balls.
2C20.60 autorotation A half round stick used as a propeller will rotate in either direction given a start.
2C20.60 curve ball A mailing tube lined with sandpaper helps give spin while throwing curve balls.
2C20.60 curve balls Throw a styrofoam ball with a throwing tube. Animation.
2C20.61 spinning ball Direct a high speed stream of air at a ball spinning on a rotating rod free to pivot perpendicular to the air stream. Pictures.
2C20.62 spinning ball device A device to spin and throw a ping pong ball. Diagrams and details.
2C20.70 Bjerknes' tube
2C20.70 mailing tube Cloth webbing wrapped around a mailing tube is jerked out causing the tube to spin through a loop the loop motion.
2C20.70 bernoulli loop the loop Pulling a cord wrapped around a mailing tube spins it into a loop the loop path.
2C20.70 Bjerknes' tube Wrap three feet of cloth tape around the middle of a mailing tube and give a jerk. The tube does a loop-the-loop.
2C20.72 bernoulli cups Glue the rims of two styrofoam cups together and launch by letting them roll off the fingers while throwing. Four glued together works better.
2C20.75 Bernoulli pen barrel
2C20.75 pen barrel bernoulli Remove the filler from a ball point pen, place under your thumbs at the edge of the lecture bench. Pop the barrel out from under your thumbs giving it lots of spin.
2C20.80 Flettner rotator
2C20.80 Flettner rotor ship on air track An aluminum can spun with a battery operated motor (and reversing switch) is mounted on an air track cart. A vacuum cleaner exhaust provides the cross wind.
2C20.80 Flettner rotator Direct an air stream at a rotating vertical cylinder on a light car. The car will move at right angles to the air stream.
2C20.80 Flettner rotator A car with a spinning styrofoam cylinder moves perpendicular to an air stream. Animation.
2C20.85 Magnus effect Construction details for a very light cylinder and a method of spinning and releasing. Diagram. ALSO - Vertical motorized cylinder on a cart.

30. Viscosity

2C30.10 viscosity disc
2C30.10 viscosity disc A horizontal disc is hung on a single thread and a second disc is spun below it causing deflection.
2C30.11 viscosity disc A disc is spun between two parallel plates of a platform balance and the deflection is noted.
2C30.12 viscosity disc A metal sheet and a disc are mounted parallel in a container of fluid. Rotate the disc and observe the displacement of the sheet by projection.
2C30.13 viscosity - viscosimeter Coaxial cylinders are separated by a fluid. As the outer cylinder is rotated, the drag induced motion of the inner cylinder is observed by optical lever magnification.
2C30.15 pulling an aluminum plate Use a string and pulley to a mass to pull an aluminum plate out of a viscous fluid ( GE Silicone Fluid, SF-96/10,000).
2C30.20 viscocity in capillary A Mariotte flask with a capillary out on the bottom permits varying the pressure at cm of water.
2C30.25 viscosity of oil
2C30.25 viscosity of oil Invert several sealed tubes filled with oil. Air bubbles rise.
2C30.25 oil viscosity Quickly invert tubes of oil and watch the bubbles rise to the top.
2C30.30 temperature and viscosity Tubes filled with motor oil and silicone oil are inverted at room temperature and after cooling with dry ice/alcohol.
2C30.30 viscosity and temperature Rotate a cylinder of castor oil in a water bath on a turntable. Heated from 5-40 C, the viscosity falls 15:1.
2C30.45 termimal velocity - drop balls Precision ball in a precision tube.
2C30.50 terminal velocity in water, glycerin
2C30.50 terminal velocity in water, glycerin Drop balls in large 1 meter test tubes, one filled with water, the other with glycerine.
2C30.50 terminal velocity - drop balls A steel ball is dropped into a graduate filled with oil.
2C30.50 viscous drag Steel, glass, and lead balls are dropped in a tall cylinder filled with glycerine.
2C30.51 terminal velocity - diameter Steel balls of different diameters are dropped in glycerine.
2C30.52 terminal velocity - diameter Three steel balls of different diameters are sealed in a 4' tube. Illuminate with a lamp at the bottom.
2C30.53 terminal velocity - specific gravity Four balls of the same diameter with carefully adjusted specific gravity are dropped in glycerine.
2C30.55 ball drop
2C30.55 terminal velocity - styrofoam ball A 2" dia. styrofoam ball reaches terminal velocity in 5 1/2 m.
2C30.55 ball drop Several balls including styrofoam balls of three diameters are dropped four meters. Use stop frame and take data.
2C30.56 terminal velocity - dylite beads Dylite beads reach terminal velocity quickly in water, and when expanded by heating in boiling water, are also useful in air.
2C30.60 terminal velocity - styrofoam
2C30.60 terminal velocity - styrofoam Drop styrofoam half round packing pieces.
2C30.65 terminal velocity coffee filters
2C30.65 terminal velocity coffee filters Drop a coffee filter and it descends with low terminal velocity. Crumple one and drop it.
2C30.65 air friction Drop crumpled and flat sheets of paper.

40. Turbulent and Streamline Flow

2C40.01 swimming bacteria A transcription of an interesting talk about the world of low Reynolds number.
2C40.10 streamline flow
2C40.10 streamline flow The Cenco streamline flow apparatus.
2C40.10 streamline and turbulent flow A simple streamline apparatus for use on the overhead projector that uses a ganged syringe ink source.
2C40.10 streamline flow A commercial apparatus to show flow around objects in projection cells.
2C40.11 streamline flow Directions for construction a streamline flow apparatus that uses several potassium permanganate tracers.
2C40.12 streamlines a simple gravity streamline apparatus.
2C40.14 streamlines on the overhead Flow is shown between two glass plates from a source point to a collection point. Dilute NaOH passes a ring of phenophthalein beads around the source generating colored trails.
2C40.14 inverse square law patterns Inverse-square-law field patterns are illustrated by dyed streamlines of water flowing between two glass plates. Construction details in appendix, p. 620.
2C40.16 dry ice fog Some dry ice in a flask of warm water will produce a jet of fog that can be used with a fan to show the effects of various objects on air flow.
2C40.17 streamline design The effect of moving air on a disc and streamlined object of the same cross section is demonstrated.
2C40.18 fluid mappers Several types of fluid mappers. Pictures and diagrams. Construction details in appendix, p. 614.
2C40.20 streamline flow - blow out candle Place a lighted candle on one side of a beaker and blow on the other side to put out the candle.
2C40.21 streamline flow - blow out candle A technique to blow a card over using upward curling streamlines.
2C40.25 Poiseuille flow
2C40.25 Poiseuille flow Colored glycerine is placed on top of clear glycerine in a square cross sectioned tube and a stopcock is opened at the bottom to adjust flow.
2C40.25 streamline flow Watch the interface between clear oil on the bottom of a glass tube and colored oil on top as oil is drawn off the bottom.
2C40.30 vena contracta As a liquid emerges vertically downward, its jet contracts in diameter.
2C40.50 laminar and turbulent flow
2C40.50 laminar and turbulent flow An ink jet is introduced at different rates into a tube of flowing water.
2C40.50 turbulent flow The velocity of a stream of ink is varied in smoothly flowing water.
2C40.51 Reynold's number A tapered nozzle introduces tracer fluid into a tube at the bottom of a reservoir.
2C40.51 Reynold's number A device for varying the flow in a tube and introducing a tracer into the flow. Several hints. Reference: AJP 28(2),165.
2C40.52 Reynold's number A funnel feeds methylene blue into a vertical tube with adjustable water flow.
2C40.52 Reynolds' number Water with potassium permanganate flows through a vertical tube. Flow is varied and rate is determined by timing 1 liter.
2C40.53 Reynolds' number The flow rate in a long thin brass tube is adjusted until spitting starts. Flow rate is determined by collecting water for a given time.
2C40.60 laminar and turbulent flow Shadow project rising warm air flowing around objects.
2C40.61 streamline vs. turbulent flow Drop a ball into a viscous liquid or water. Shadow project a hot iron ball in slowly or rapidly moving air.
2C40.63 laminar and turbulent flow The Krebs apparatus is used to show flow of water around objects.
2C40.71 laminar & turbulent flow A discussion of the various types of friction involving the air track.
2C40.73 stero shadowgraph On viewing fluid flow with stereo shadowgraphs.
2C40.80 weather maps Daily weather maps show large scale fluid dynamics.
2C40.90 Rayleigh-Taylor instability in Prell A air bubble rising in a tube of Prell shampoo demonstrates Rayleigh-Taylor instability. Other examples are given.

50. Vorticies

2C50.10 smoke ring Tap smoke rings out of a coffee can through a 1" dia. hole.
2C50.10 smoke ring Smoke rings are tapped out of a coffee can through a 1" dia. hole.
2C50.10 vortex rings Tap smoke rings out of a can with a rubber diaphragm on one end and a hole in the other.
2C50.11 smoke rings with LP gas A rubber sheet at the back on a large wooden box is struck with a hammer to produce smoke rings capable of knocking over a plate. Fuming HCL and conc. ammonia produce the smoke.
2C50.12 vortex box A 15 inch square, 4 inch deep vortex box with a 4 inch diameter hole.
2C50.15 vortex cannon
2C50.15 vortex cannon Use a large barrel to generate a smoke ring. Blow out a candle with the vortex. Animation.
2C50.20 liquid vortices
2C50.20 liquid vortices A drop of inky water is allowed to form on a medicine dropper 1" above a beaker of water. This height is critical. The vortex will rebound if the beaker is less than 4" deep.
2C50.21 ring vortices on liquid Bursts of colored water are expelled from a glass tube in a beaker of water. Also a drop of aniline sinks in a beaker of water.
2C50.22 semicircular vortex in water A skill demonstration. Use a small paddle to form vortices in a small dish on the overhead projector.
2C50.23 detergent vortex A few drops of detergent in a jar of water are shaken and given a twist to form a vortex lasting several seconds.
2C50.25 whirlpool Water is introduced tangentially into a cylinder with a hole in the bottom.
2C50.30 tornado tube
2C50.30 tornado tube
2C50.30 tornado vortex A vortex forms in a large cylinder on a magnetic stirrer.
2C50.30 tornado tube Couple two soft drink bottles with the commercial tornado tube coupler and spin the top bottle so the water forms a vortex as it drains into the bottom bottle.
2C50.35 flame tornado
2C50.35 paraboloids and vortices A transparent cylinder is rotated at speeds up to 1000 RPM.
2C50.40 growing a large drop A vortex is formed in an air stream allowing one to form a large water drop.

60. Non Newtonian Fluids

2C60.10 fluidization A bed of silica powder acts like a fluid when air is forced through it. Diagram.
2C60.20 density balls in beans
2C60.20 rising stones Rising of rocks in the spring is the same as the sifting of fine particles to the bottom of a cereal box.
2C60.20 density balls in beans A ping pong ball in the middle of a beaker of beans will rise when the beaker is shaken.
2C60.22 Beans The size of an aluminum ball determines whether it goes up or down in a shaking bowl of beans.
2C60.30 cornstarch
2C60.30 cornstarch Add water to cornstarch until it is goo. Pour it, throw it, punch it.
2C60.35 slime ball
2C60.35 slime ball A commercial product "Slime" flows like a liquid under normal conditions but bounces on impact.
2C60.40 silly putty
2C60.40 silly putty
2C60.50 fluids vs. solids Asphalt splinters when smashed but flows gradually, sand flows when poured but remains in a conical pile.
2C60.55 ketchup uzi
2C60.55 ketchup uzi Fill a super soaker with ketchup. Shoot it across the room and it blobs on the wall.