PHYSICS DEPARTMENT
LIST OF
DEMONSTRATIONS USING THE PIRA SCHEME
The goal of the PIRA Demonstration Classification Scheme is
to create a logically organized and universally inclusive taxonomy giving a
unique number to every lecture demonstration. The structure of the
classification system is as follows:
Example: 1C10.25 Glider on Air Track
|
1 |
Area |
(mechanics) |
|
C |
Topic |
(motion in one dimensions) |
|
10 |
Concept |
(velocity) |
|
.25 |
Demonstration |
(Glider on Air Track) |
AVAILABLE DEMOS ARE IN BOLD
I. MECHANICS
1. Basic Units 1A10.00
2. Error and Accuracy 1A20.00
a. Catch a
Meter Stick 1A20.60 (Jacobs B122-285)
CATCH A METER STICK 1A20. 60
- Hold a meter stick up and have a student volunteer hold his fingers beside the 50cm point.
-Ask the student to grab the meter stick the instant he sees you drop it.
-Drop the meter stick.
-After the student catches the meter stick, measure the distance from the 50cm mark to the point where he caught the meter stick.
-Convert distance to reaction time: t = square root of (2d/g).
3. Coordinate Systems 1A30.00
4. Vectors -1A40.00
5. Math Topics 1A50.00
6. Scaling 1A60.00
Motion In One Dimension 1C00.00
1.
Velocity - 1C10.00
a. Glider on Air track 1C10.25 (Galileo F)
GLIDER ON AIR TRACK 1C10.25
- To demonstrate velocity in one dimension set a glider in motion on an air track
2.
Uniform Acceleration 1C20.00
a. Inclined Air Track 1C20.30 (Galileo
F)
INCLINED AIR TRACK 1C20.30
- Air track will be leveled. Place aluminum blocks under single leg of air track to create desired incline.
- Turn on the air supply.
- To find the average velocity by using two photo gates.
. 3.
Measuring g 1C30.00
Motion In Two Dimensions 1D00.00
1.
Displacement in Two Dimensions 1D10.00
2.
Velocity, Position, and Acceleration 1D15.00
a.
- First ask the class to predict which ball will win
- Both tracks are the same angle, except for the transition segments.
4.
Central Forces 1D50.00
a. Pail of Water 1D50.40 (Jacobs
B122-374)
PAIL OF WATER 1D50.40
- Swing pail in a large vertical circle
b. Rolling Chain - 1D50.70 (Galileo F)
ROLLING CHAIN 1D50.70
- The chain is mounted on the motor.
- Start the motor by turning on the switch
- Abruptly push the chain away from the motor
- Chain will roll to a distance before it collapses.
5.
Deformation by Central Forces 1D52.00
a. Flattening the Earth 1D52.10 (Jacobs
B122-283)
FLATTENING THE EARTH 1D52.10
- Hang the Hoberman Sphere.
- Rotate the sphere and, like the Earth, it becomes oblate.
- Its equator moves outward and its poles draw together.
- Central forces push the spheres center outwards, narrowing its radius.
a. Water Parabola 1D52.20 (Jacobs B122-279)
WATER PARABOLA 1D52.20
- A rectangular flat glass container mounted on ball bearings
is filled with colored water and spun.
- As
the setup rotates, one can observe the parabolic curve formed by the water's
surface.
6. Centrifugal Escape 1D55.00
a. Broken Ring
on Overhead Projector 1D55.10 (Jacobs B122-286)
BROKEN RING (OHP) 1D55.10
- Place the ring near the edge of the table so that the ball will roll parallel to the edge.
- Roll a steel ball around the inside of the ring.
- Hold the ring securely while the ball is rolling around the ring.
- Have the class vote which way the ball will roll when it reached the gap.
7.
Projectile Motion - 1D60.00
a. Funnel Cart Trajectory 1D60.10 (Galileo F)
FUNNEL CART TRAJECTORY 1D60.10
- A ball fired vertically from a cart moving horizontally falls back into the cart
b. Simultaneous Fall
1D60.20 (Jacobs B122-279)
SIMULTANEOUS FALL 1D60.20
- A Spring loaded device drops one ball and projects the other horizontally.
- Listen for the sound of balls striking the floor. Only one click should be heard.
c. The Monkey and the
Hunter 1D60.32 (Galileo
F)
THE MONKEY AND THE HUNTER 1D60.32
- Aim the cannon at the monkey when monkey is held up high.
- When the ball leaves the cannon, the monkey should drop
- The ball will hit the monkey since they fall at the same rate.
d. Projectile Launcher (
PROJECTILE LAUNCHER
- Shoot balls at different angles.
1.
Moving Reference Frames 1E10.00
2.
Rotating reference frames 1E20.00
3.
Coriolis Effect 1E30.00
1.
Measuring Inertia - 1F10.00
2.
Inertia of Rest 1F20.00
a. Smash Your Hand 1F 20.20 (Jacobs B122 352)
SMASH YOUR HAND 1F20.20
- Place a lead brick on a hand or on a piece of fruit.
- Hammer the brick, give it a good whack.
- The person doesnt howl with pain.
3.
Inertia of Motion 1F30.00
a. Persistence of Motion Cart on Air
Track 1F30.10 (Galileo
F)
PERSISTENCE OF MOTION (AIR TRACK) 1F30.10
- Air track is leveled. Turn on the air supply
- Push cart and allow it to bounce back and forth long the track
- Nearly all energy loss occurs during the collisions at the ends of the track
1.
Force, Mass and Acceleration 1G10.00
2.
Accelerated Reference Frames 1G20.00
a. Dropped Slinky 1G20.45 (Jacobs
B122-163)
DROPPED SLINKY 1G20.45
- Hold a slinky so some of it extends downward, and then drop it to show the contraction
3.
Complex Systems 1G30.00
1.
Action and Reaction- 1H10.00
a. Push Me Pull You Carts 1H10.10 (Jacobs B
122- 231A )
PUSH ME PULL YOU CARTS 1H10.10
- Hold Ask two students to stand on two different carts and hold a rope between them.
- Have only one student pull on the rope.
- Observe that they both move toward each other.
- Have the other student pull on the rope, observe the same effect.
- Use a stick instead for pushing.
- Both carts move away from each other as only one student pushes on the stick.
2.
Recoil 1H11.00
Statics and Rigid Bodies 1J00.00
1.
a. Map of State - 1J10.10 (Jacobs
B122-370)
MAP OF STATE 1J10.10
- Hang map of your state on a peg through the desired hole.
- Hand a plumb bobbin front
- Mark plump line with marker.
- Repeat with other holes.
- Where the lines cross is the center of gravity.
b. Fingers Find CG - 1J10.20
(Jacobs B122 171)
FINGERS FIND CG 1J10.20
- Hold a 2m meter-stick horizontally, with one finger under
each end.
- As the fingers slowly draw together, the meter stick slides so as to remsin
balanced.
- Try different starting points or add a small mass to one end of the stick.
2.
Exceeding Center of Gravity 1J11.00
a. Double Cone 1J11.15 (Jacobs
B122-286)
DOUBLE CONE 1J11.15
- Place the double cone on the lower end of the U and it will roll uphill.
b.
- Place wooden or metal blocks on top of each other with each progressive block hanging out farther than the last.
3.
Stable, Unstable and Neutral Equilibrium 1J20.00
a. Nine Nails on One 1J20.25 (Jacobs
B122-371)
NINE NAILS ON ONE 1J20.25
-Balance the set of 9 nails on one
b.
CENTER OF GRAVITY PARADOX STICK 1J20.26
-This center of gravity paradox shows that a lower center of mass doesnt always increase stability.
- Balance the
stick w/ attached mass
- The weight farther away works better due to its moment of inertia.
4.
Resolution of Forces 1J30.00
5.
Static Torque 1J40.00
a. Torque Beam 1J40.22 (Jacobs
B122-285 &Galileo F)
TORQUE BEAM 1J40.22
- Use combinations of masses and distances to show torques in equilibrium
-Distances are in integer multiples: r, 2r, 3r, 4r.
-Masses are equal
Applications of
1.
Dynamic Torque 1K10.00
a. Waking the
Spool 1K10.30 (Galileo
F)
WALKING THE SPOOL 1K10.30
- Pull the rope that is wound around the spool
- The angle between the rope and the table determines the direction the spool will roll.
- At some angle, the spool will not roll, but slide when you pull it.
2. Friction 1K20.00
a. Friction
Blocks Surface Materials 1K20.10 (Galileo
F)
FRICTION BLOCKS SURFACE MATERIAL 1K20.10
- Measure static friction by noting the scale reading just before the block slides.
- Measure sliding friction by pulling the block at a constant speed.
- Change the surface materials and note the different frictions.
b. Static vs. Sliding
Friction 1K20.30 (Galileo
F)
STATIC VS SLIDING FRICTION 1K20.30
- Pull on a block with a spring scale until just before the block moves.
- Note the reading on the spring scale.
- Pull the block slowly across the table.
- Compare the spring scale readings.
3. Pressure 1K30.00
a. Bed of Nails
and Balloon 1K30.15 (Jacobs B122-369)
BED OF NAILS AND BALLOON 1K30.15
- A balloon is placed on a bed of 25 nails.
- 500 g masses are placed on a board which rests on the balloon.
- The 25 nail bed is replaced with a single nail and the
procedure is repeated.
Gravity 1L00.00
1. Universal Gravitational
constant 1L10.00
a. Cavendish
Balance 1L10.30 (Keck B127)
CAVANDISH BALANCE 1L10.30
- Initially the balance is
in equilibrium with the two large lead balls in one extreme position up against
the face of the balance.
- At the start of the
lecture the balls are moved to the other extreme position.
- The suspension goes into
oscillation.
- By the end of the period
the motion of the suspension approaches a new equilibrium position brought
about by the change in the gravitational force on the dumbbells.
2. Orbits 1L20.00
1. Work 1M40.10
2.
Simple Machines 1M20.00
3.
Non-Conservative Forces 1M30.00
4.
Conservation of Energy 1M40.00
a. Loop the
LOOP THE
- Release the ball near the
top of the track.
- The energy loss makes the
minimum height necessary to complete the loop significantly higher than the
calculated value.
5. Mechanical Power 1M50.00
Linear Momentum and Collisions 1N00.00
1. Impulse and Thrust 1N10.00
2.
Conservation of Linear Momentum 1N20.00
3.
Mass and Momentum Transfer 1N21.00
4.
Rockets 1N22.00
5.
Collisions in One Dimension 1N30.00
a. Collision with 5 Hanging Balls
1N30.10 (Jacobs B122-011)
COLLISION WITH 5 HANGING
BALLS - 1N30.10
- Observe the effects of
displacing different numbers of balls.
- Try one ball first, then
two and so on up to five balls at once.
b.
- Raise a ball away from the
others and release it- It collides with its neighbor.
- The momentum of the ball is
transferred through the system.
- The ball on the other end
reacts accordingly.
- Repeat the process with
two balls, or three, or four.
- This demonstrates
conservation of momentum in a collision involving several bodies.
c. Large Ball and Small Ball Drop 1N30.60 (Jacobs
B122-273 & 275)
LARGE BALL AND SMALL BALL
DROP 1N30.60
- Place a small ball on top
of a big ball and drop from a height of about 4 feet
d. Velocity Amplifier
using Stacked Disks 1N30.62 (Galileo
F)
VELOCITY AMPLIFIER USING
STACKED DISKS 1N30.62
- Four discs (1 5/8", 3 1/8", 5", and 8") are placed on top of each other such that they stand vertically.
- The four discs are also confined to the vertical plane.
- Raising and releasing two discs will cause the smallest disc to bounce a few inches.
- Raising three will cause the smallest disc to bounce out of the apparatus a few inches.
- Raising and releasing all four will cause the smallest disc to fly many feet into the air.
e. Double Air Glider Bounce on an Air Track
1N30.65 (Galileo
F)
DOUBLE AIR GLIDER BOUNCE
1N30.65
- Let two air carts
accelerate down an inclined air track
- Vary the mass of the first
cart and measure the rebound height of the smaller cart
6. Collision in Two Dimensions
1N40.00
a. Super Ball
Bounces 1N40.60 (Jacobs B122-280)
SUPER BALL BOUNCES 1N40.60
- A super ball is bounced
under a flat surface, such as a table.
- The super ball then
bounces back.
- Bounce the ball at a 45
degree angle to the ground for good results.
PASCOS Complete Rotational System provides a range of experiments in
centripetal force, angular momentum and rotational motion (Galileo
F)
1.
Moment of Inertia 1Q10.00
a. Inertia Wands 1Q10.10 (Galileo F)
INERTIA WANDS 1Q10.10
- Twirl equal mass wands,
one with the mass at the ends and the other with the mass at the middle.
- The wand with the mass
concentrated in the middle rotates much easier than the wand with the mass
concentrated at the ends.
b. Ring, Disk and Sphere
Race (rolling on incline) 1Q10.30
RING,
DISK AND SPHERE RACE 1Q10.30 (Galileo
F)
- Each item has the same
diameter
- After leveling the track
from side release them all at the same time and see which one gets to the
bottom first.
- To release all objects at
the same time, place a meter stick against the supports. With objects resting
against the meter stick, remove the stick quickly with an upward motion.
2.
Rotational Energy 1Q20.00
a.
Complete Rotation Demonstration (
- The system provides a
range of experiments in centripetal force, angular momentum and rotational
motion
b. Driven
Torsion Oscillation- Indian Driller 1Q20.21
DRIVEN TORSION
OSCILLATION Indian Driller 1Q20.21 (Galileo
F)
-Indian Driller to show rotational
energy.
3.
Transfer of Angular Momentum 1Q30.00
a. Passing the Wheel 1Q30.10 (Galileo
F)
PASSING THE WHEEL 1Q30.10
- Tip the spinning tire half
way and hand it to a student on a turntable
- The student tips it
another half way and hands it back.
- Repeat until the spinning
student is turning so fast for the hand off.
- Add or subtract from the
angular momentum depending on which way the wheel is tipped.
b. Driven Torsion
Oscillation- Indian Driller 1Q30.12 (Galileo F)
DRIVEN TORSIOAN OSCILLATION INDIAN
DRILLER 1Q30.12
-Indian Driller to show transfer of
angular momentum,
4. Conservation of Angular
Momentum 1Q40.00
a. Rotating
Stool with Weights 1Q40.10 (Galileo F)
ROTATING STOOL WITH WEIGHTS
1Q40.10
- Start rotating with
dumbbells close to your body. Or else be careful to begin with a slow spin.
- Watch the change in spin
the masses are moved further away.
b. Rotating
Hoberman Sphere 1Q40.22 (Jacobs B122 - 283)
ROTATING HOBERMAN SPHERE
1Q40.22
- Expand the Hoberman sphere by removing the small clip at the bottom.
- Give the sphere a slight push to make it spin slowly.
- As it is spinning, pull on the bottom pull ring and watch the angular velocity change.
- Do not pull hard enough to collapse the sphere completely. This damages the pulley system.
c. Pulling on the Whirligig 1Q40.25 (Jacobs
B122 - 375)
PULLING ON THE WHIRLIGIG
1Q40.25
- Attach balls to either ends of a string that passes through a hollow tube so you can set one ball twirling and pull on the other ball to change the radius.
- Spin the ball around while holding the hollow tub.
- Move the lower ball up and down to change the radius of the circle.
d. Rotating Stool and the Bicycle Wheel
1Q40.30 (Galileo F)
ROTATING STOOL AND BICYCLE WEEL 1Q40.30
- Tip a spinning wheel sitting on a rotating platform.
- Tip the wheel in the opposite direction to spin to change the direction on the spinning platform
e. Suitcase Demo 1Q40.50 (Jacobs
B122 - 033)
SUITCASE DEMO 1Q40.50
-A large fly-wheel is mounted in a suitcase.
-Start the fly-wheel a couple of minutes before the demo.
-Have a student carry the suitcase around the corner.
f. Heros Engine 1Q40.80
HEROS ENGINE 1Q40.80
- Put an amount of liquid nitrogen in the bottle and tighten the bottle to the cap and PVC pipe assembly.
- Hold the other end of the PVC firmly and lower the bottom of the bottle into a container (Nalgene beaker) 1/3 full of water.
- As soon as the bottom of the bottle touches the water the liquid nitrogen will begin to boil and pressurize.
- The nitrogen gas escaping will cause the bottle to run at a high rate of speed.
5.
Gyros 1Q50.00
a. Precessing Gyro 1Q50.50 (Galileo F
& Small Gyros Jacobs B122-280)
PRECESSING GYRO 1Q50.50
- A gyroscope with a counterweight is used to show the fundamental precession equation.
6. Rotational Stability 1Q60.00
a.
Lazy Suzan with Spring Scales -
LAZY SUZAN 1Q6001
-Lazy Suzan to show rotational stability.
b. Stacking Wooden Blocks -
STACKING WOODEN BLOCKS 1Q60.02
- Stacking wooden blocks to show rotational stability.
Properties of Matter 1R00.00
1. Hookes Law
a.
Stretching a Spring 1R10.10 (Jacobs B122 - 168)
STRETCHING A SPRING 1R10.10
- A 50 gram mass hanger hangs on a spring
- Begin with 50 grams on the hanger. This brings the spring into its linear range.
- Mark the position of the bottom of the hanger on a meter stick positioned next to it with a clamp.
- Add 100 gram masses to the hanger marking the positions after each addition.
- Compare the end positions of masses that are multiples,
such as double or triple.
2. Tensile and Compressive Stress 1R20.00
3. Shear stress 1R30.00
4. Coefficient of Restitution 1R40.00
a. Happy and
Sad Balls 1R40.30 (Jacobs B122 - 166)
HAPPY AND SAD BALLS 1R40.30
- Drop bounce and no bounce balls.
- Measure the height the bouncing ball is dropped from and the height it bounces to and calculate the coefficient of restitution.
- The sad ball will not bounce as it is made from energy absorbing material.
5. Crystal Structure 1R50.00
II. FLUID MECHANICS
1. Force of Surface Tension 2A10.00
a.
Floating Metals 2A10.20 (Jacobs B122 - 022)
FLOATING METALS 2A10.20
- Place the needle on a bit of tissue and place on the surface of fresh water.
- Sink the tissue with a stick, leaving the needle floating.
- Add a little soap to sink the needle.
b.
Surface Tension Bottle 2A10.60 (Jacobs B122 - 280)
SURFACE TENSION BOTTLE 2A10.60
- A flask has a screw top cork with a small hole.
- Insert a slender object through the hole to show that a hole indeed exists,
- Fill the flask with water and insert the cork and invert it.
- No water will exit through the hole.
2. Minimal Surface 2A15.00
a.
Soap Film 2A15.10 (Jacobs B122 - 022)
SOAP FILM 2A15.10
-Dip a frame with a loop of thread in soap. Pop the film in the center of the thread by blowing on it. The formula for the solution is: ½ gallon (1890 ml) distilled water, 1/3 cup (80 ml) Dawn, 1Tablespoon (7.5 ml) Glycerin.
3. Capillary Action 2A20.00
4. Surface Tension Propulsion 2A30.00
1. Static Pressure 2B20.00
2. Atmospheric Pressure 2B30.00
a.
Crush the Soda Can 2B30.10 (Jacobs B122 - 022)
CRUSH THE SODA CAN 2B30.10
- Put a small amount of water in a soda can.
- Partially fill the bowl with water.
- Bring water in the can to a boil.
- Using tongs, flip the can over into bowl of cold water
- Watch the can immediately collapse.
b.
- Use a hand pump to evacuate the
- About 140 pounds of force are needed to separate them.
c.
Vacuum Cannon -2B30.70 (Galileo F & Jacobs B122 149 and 281)
VACUUM CANNON 2B30.70
- Place the vacuum cannon on the table and clamp the pop can holder directly in front of the cannon muzzle.
- Place a 40mm Ping-Pond ball into the muzzle and roll it all the way down to the stop provided by the vacuum inlet.
- Place 3-M packing tape onto each end of the cannon taking care to insure that the tape is flat so that it does not have any air leaks.
- Pump the air out of the cannon with the vacuum pump.
- When desired vacuum is reached, shut the valve on the cannon and turn off the vacuum pump.
- Using a sharp object, puncture the tape at the rear end of the cannon.
- The Ping-Pong ball will be driven out the other end of the cannon by the inrushing air and will puncture several soda cans.