Table of Fluid Mechanics

Fluid Mechanics (2B): Statics Of Fluids

Lecture Demonstrations

Dynamics of Fluids

PIRA classification 2C

2C10. Flow Rate


Demonstration Name



Toricelli's Tank

Water streams from holes at different heights in a vertical glass tube.


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.


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.


Pressure Drop Along a Line

Open tubes along a glass tube show pressure drop along a line.



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.


Syringe Water Velocity

Squirt water out of a syringe. The water moves faster through the constriction.

2C20. Forces in Moving Fluids


Demonstration Name



Hydrodynamic Attraction

Move a small sphere in water and another in close proximity will move due to hydrodynamic attraction.


Venturi Tubes

A series of manometers measures pressure of flowing air at points along a restricted tube.


Big Venturi Tubes

This version is bigger and uses ping pong balls as floats.



A jet of air is blown across one end of a "U" tube.


Pitot Tube ?(PIRA LOCATION)?

?A pitot tube is connected to a water manometer and the air stream velocity is varied. Graphics.


Bernoulli Ball

A ball is suspended in an upward jet of air.


Oscillating Bernoulli Balls

An air jet keeps two balls at the high edge of semicircular tracks.


Ball and Cup

Air blowing out an inverted funnel will hold up a ball.


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.


Lifting Plate

Air blows radially out between two plates. This allows them to support masses. See AJP 71(2), 176.


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. Blow into a spool and lift a paper with a pin stuck through into the hole in the spool.


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.


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.


Attracting Sheets

Blow an air stream between two parallel cards on bifilar suspensions. Also try with two large balls.


Sticking Paper Flap

A stream of air blown between a paper and a surface will cause the paper to cling to the surface.


Airplane Wing

A balanced model airplane with big wings shows lift when a stream of air is directed onto it. Pressure censors show the Bernoulli effect.


Paper Lift

Hold one edge of a sheet of paper horizontally and let the rest hang. Blow across it and watch the sheet rise.


Airplane Wing

Connect a slant manometer to holes on the top and bottom of an airfoil. See Sutton M-303.


Raise the Roof

Air blown over a model house raises the roof.


Paper Dirigible

A paper loop in an air stream and a falling card. See AJP 44(8), 780.


Rayleigh's Disk

A lightweight disk turns perpendicular to the air flow.



An article explaining boomerang flight along with directions for throwing and building one. See TPT 28(3), 142.


Fly Wing Mechanism

How to build a working model of Pringle's fly wing mechanism. See AJP 45(3), 303.


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. See AJP 29(7), 459.


Dropping Wing Sections

A folded index card, a paper pyramid, or a paper cone are stable when dropped apex down.



A model airplane is used to demonstrate the principles of lift and air drag. It can also be used in the discussion of airfoils. See AJP 55(1), 50, TPT 28(2), 84, and TPT 28(2), 78.


Curve Ball

Throw a 3" polystyrene ball with a "V" shaped launcher lined with emery cloth.


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. See AJP 76(2), 119.


Mailing Tube

Cloth webbing wrapped around a mailing tube is jerked out causing the tube to spin through a loop the loop motion.


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.


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. See AJP 47(2),200.


Bernoulli Pen Barrel

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.


Flettner rotator

Direct an airstream at a light car with a large rotating stryofoam cylinder. The car will move at right angles to the airstream. Could be used with the air track.


Magnus Effect

Construction details for a very light cylinder and a method of spinning and releasing. Diagram. ALSO - Vertical motorized cylinder on a cart.



An analysis of how a Frisbee works. See TPT 21(5), 325.

2C30. Viscosity


Demonstration Name



Viscosity Disc

A horizontal disc is hung on a single thread and a second disc is spun below it, causing deflection. See Sutton M-62.


Viscosity Disc

A disc is spun between two parallel plates of a platform balance and the deflection is noted. See Sutton M-61.


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. See Sutton M-56.


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. See Sutton M-55.


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).


Viscocity in Capillary

A Mariotte flask with a capillary out on the bottom permits varying the pressure at cm of water. See AJP 33(10),848.


Oil Viscosity

Quickly invert tubes of oil and watch the bubbles rise to the top. Air bubbles rise at different speeds in different fluids.


Temperature and Viscosity

Tubes filled with motor oil and silicone oil are inverted at room temperature and after cooling with dry ice/alcohol. Or, use castor oil from 5 to 50 C the viscosity goes down by a factor of 15.


Terminal Velocity - Drop Balls

Precision ball in a precision tube.

2C30.50 1C10.51

Terminal Velocity With Water, Glycerin, & Marbles

Two identical marbles are dropped simultaneously into separate graduated cylinders, one filled with glycerine and the other with water. The marble dropped in glycerine will quickly reach terminal velocity, obtaining a slow and constant velocity that can be measured.


Terminal Velocity - Diameter

Three steel balls of different diameters are sealed in a 4' tube. Illuminate with a lamp at the bottom.


Terminal Velocity - Specific Gravity

Four balls of the same diameter with carefully adjusted specific gravity are dropped in glycerine.


Terminal Velocity - Styrofoam Ball

A 2" dia. styrofoam ball reaches terminal velocity in 5.5m. Use a stop frame and take data.


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.


Terminal Velocity coffee Filters

Drop a coffee filter and it descends with low terminal velocity. Crumple one and drop it.


Air Friction

Drop crumpled and flat sheets of paper.

2C40. Turbulent and Streamline Flow


Demonstration Name



Streamline Flow

The Cenco streamline gravity flow apparatus. A commercial apparatus to show flow around objects in projection cells. See Sutton M-306.


Streamline Flow

A streamline flow apparatus that uses several potassium permanganate tracers.


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. See AJP 37(9), 868.


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.


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. See Sutton M-307.


Streamline Design

The effect of moving air on a disc and streamlined object of the same cross section is demonstrated.


Fluid Mappers

Several types of fluid mappers. Pictures and diagrams. Construction details in appendix, p. 614.


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.


Streamline Flow - Blow Out Candle

A technique to blow a card over using upward curling streamlines. See Sutton M-309.


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. Or, 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. See Sutton M-310.


Vena Contracta

As a liquid emerges vertically downward, its jet contracts in diameter. See Sutton M-254.


Laminar and Turbulent Flow

The velocity of a stream of ink is varied as it is introduced into a tube of smoothly flowing water.


Reynold's number

A tapered nozzle introduces tracer fluid into a tube at the bottom of a reservoir.


Reynold's Number

An apparatus for varying the flow in a tube and introducing a tracer into the flow. Different fluids can be used. See AJP 28(2), 165.


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. This lets one determine


Laminar and Turbulent Flow

Shadow project rising warm air flowing around objects.


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. See Sutton M-311.


Laminar and Turbulent Flow

The Krebs apparatus is used to show flow of water around objects.


Stero Shadowgraph

On viewing fluid flow with stereo shadow-graphs. See AJP 44(10), 981.


Rayleigh-Taylor Instability in Prell

A air bubble rising in a tube of Prell shampoo demonstrates Rayleigh-Taylor instability. Other examples are given. See AJP 53(5), 484.

2C50. Vortices


Demonstration Name



Smoke Rings

Tap smoke rings out of a box with a rubber diaphragm on one end and a hole in the other.


Smoke Rings with LP Gas

A rubber sheet at the back of 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.


Vortex Box

A 24 inch square, 8 inch deep vortex box with a 4 inch diameter hole.


Vortex Cannon

Use a large barrel to generate a smoke ring. Blow out a candle with the vortex. Animation.


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. See Sutton M-253.


Semicircular Vortex in Water

A skill demonstration. Use a small paddle to form vortices in a small dish on the overhead projector.


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. See TPT 28(7), 494.



Water is introduced tangentially into a cylinder with a hole in the bottom.


Tornado Vortex

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.


Fire Tornado

A rotating cylinder of copper mesh surrounds a dish with burning material in it. The air flow due to the spinning mesh causes the flames to take on a signature tornado shape.


Paraboloids and Vortices

A transparent cylinder is rotated at speeds up to 1000 RPM. See AJP 37(9), 864.


Growing a Large Drop

A vortex is formed in an air stream allowing one to form a large water drop.

2C60. Non Newtonian Fluids


Demonstration Name




A bed of silica powder acts like a fluid when air is forced through it. Diagram.


Rising Stones

A ping pong ball in the middle of a beaker of beans will rise when the beaker is shaken. Rising of rocks in the spring is the same as the sifting of fine particles to the bottom of a cereal box.



The size of an aluminum ball determines whether it goes up or down in a shaking bowl of beans.



Add water to cornstarch until it is goo. Pour it, throw it, punch it.


Cornstarch on Speaker

Cover a speaker cone in the cornstarch suspension and turn it on.


Slime Ball

A commercial product "Slime" flows like a liquid under normal conditions but bounces on impact.


Fluids vs. Solids

Asphalt splinters when smashed but flows gradually, sand flows when poured but remains in a conical pile. See Sutton M-253.


Ketchup Uzi

Fill a super soaker with ketchup. Shoot it across the room and it blobs on the wall.