Follow

PHYS131

  • C4-34: GALILEO'S EXPERIMENT - MASSES IN FREE FALL

    C4-34
    Show that the acceleration of bodies in free fall is independent of mass
    Light and heavy balls are weighed using the spring scale. When they are dropped simultaneously from a height of about ten feet, they accelerate downward at the same rate (the acceleration of gravity) and reach the floor at the same time. A wooden board acts as a sound board to amplify the sound when they reach the floor.
    C4, OS0

  • C4-52 WEIGHTLESSNESS IN FREE FALL - MASS IN CUP ON POLE

    C4-52
    Illustrate apparent weightlessness in free fall
    A mass hangs from a spring over the edge of a cup. Raise the pole vertically and release. Because the mass becomes weightless in free fall, the ball will be pulled into the cup immediately when the system begins to fall.

  • C5-14 ROCKET TRIKE

    C5-14
    Demonstrate Newton's third law of motion

    Pressing the fire extinguisher handle expels carbon dioxide out a nozzle straight behind the tricycle, causing forward thrust of the tricycle. Be sure the exhaust is not oriented to hit the audience or anything else likely to be adversely affected but a sudden blast of cold air.
    Background
    This is a dramatic illustration of Newton's Third Law of Motion: the principle of action and reaction. The mass of gas being ejected out of the back of the tricycle at a very high velocity imparts an equal and opposite force to the tricycle, which thus moves forward. The tricycle is much more massive, so it does not move as quickly, but the acceleration is still very real - be careful not to run into the wall!
    FS1

  • C5-18 FAN CART

    C5-18
    Demonstrate Newton's third law of motion
    This small wheeled cart has a battery-powered fan mounted on it, and a slot at the end that can hold a plastic sail. With the sail off, turning on the fan drives the cart in the direction opposite the blowing air. With the sail on and the fan off, blowing on the sail will drive it in the direction you blow. With the sail on and the fan on, the sail visibly flexes, but the cart goes nowhere at all. The force acting on the sail is such that it exactly cancels.

    Note: The fan spins quite fast. Don't let it hit your fingers! To connect and disconnect power, use the alligator clip wire on the rear; clip it to the fan support frame for safety when not in use.

    Consider inviting students to make predictions about the cart's behaviour with and without the sail. Invite them to discuss the forces involved.
    C5

  • C6-02: INCLINED PLANE - FRICTION BLOCK

    C6-02
    Demonstrates that the coefficient of static friction is greater than the coefficient of sliding friction, and determines the coefficient of static friction.
    Position the block on the incline and slowly increase the angle until the block begins to slide down the incline. Because the coefficient of static friction is greater than the coefficient of sliding friction, after the block starts sliding it will continue to slide.
    C6

  • C7-11: COLLISIONS OF BALLS - EQUAL MASSES

    C7-11
    Demonstrates conservation of energy and conservation of linear momentum in multiple elastic collisions
    Hold one, two, three, or four balls to the side and release. Symmetric oscillations result from conservation of energy and conservation of linear momentum in the collision sequence.

    Click here to go to a simulation of this device by Erik Neumann.
    C7

  • C7-17 SUPERBALL

    C7-17
    Illustrates nearly elastic collisions
    Drop the superball and watch it bounce
    C7

  • C7-19: GAUSSIAN GUN

    C7-19
    Demonstrate transfer of energy in an elastic collision
    Ball bearings in a track are accelerated by a magnetic field, showing a collision where momentum appears to not be conserved.

    Compare to K2-40: Magnetic Accelerator
    OS0

  • C7-22: COLLISION OF BALL WITH STUDENT

    C7-22
    Involve students with collisions.
    Throw ball at student. Discuss details of the resulting collision.

  • C7-23: MEDICINE BALL AND SKATEBOARD

    C7-23
    Demonstrate large-scale collisions
    Throw medicine ball to student sitting on skateboard. Student sitting on skateboard can throw medicine ball off.

  • C7-25: SUPERBALL, VACUUM MUD AND WOOD BLOCK COLLISIONS

    C7-25
    Show that a larger impulse is imparted by an elastic collision.
    A vacuum mud ball at the end of a rod is held horizontally and released so that it swings into a wooden block. The vacuum mud ball is replaced by a superball with the same mass, and the experiment repeated. Q: In which of these cases will the wood block be knocked over? A: The superball knocks over the wooden block because it bounces back, imparting more momentum to the block.
    C7, FS2

  • C7-42: AIR TABLE - COLLISIONS OF PUCKS

    C7-42
    Qualitatively demonstrate elastic and inelastic two-dimensional collisions.
    Two or more pucks can be used to demonstrate elastic collisions. Velcro collars on pucks (front row of second picture) produce perfectly inelastic collisions. The air table is only available in rooms 1410, 1412, and 0405 because it will not fit through a standard single door. In smaller rooms, please consider C7-43 or C7-44.

    Also see a simulation of similar collisions here: https://www.myphysicslab.com/engine2D/billiards-en.html

  • C8-03: GALILEO'S PENDULUM

    C8-03
    Demonstrate conservation of energy in a simple system.
    The pendulum is hung from the upper peg with the lower peg interrupting its swing to the right. When started from the left at a given height, the pendulum rises to that same height on the right, after being stopped by the lower peg.

    See demonstration G1-20 to explore more complexities of this setup.
    FS2

  • C8-04 HILL TRACK

    C8-04
    Demonstrates conservation of energy
    A ball is placed at some point on the left side of the track and released. The motion of the ball down the track and over the hill can be described in terms of gravitational potential energy and kinetic energy. The ball must be released at some minimum height in order to pass over the hill.
    OS0

  • C8-05: CONSERVATION OF ENERGY IN VERTICAL PROJECTILE

    C8-05
    Show the relation between initial velocity and height of a vertical projectile.
    A projectile is launched vertically. The laser and photocell timer setup is used to determine the initial upward velocity of the projectile. The height is measured using the scale behind the projection device. The measured height h and the measured velocity v are related by the equation v**2 = 2 gh, where g is the acceleration of gravity. Result is good to better than ten percent.
    C8, LS1, ME1

  • C8-11 INTERNAL VS. EXTERNAL ENERGY - SPRING-COUPLED SUPERBALLS

    C8-11
    Shows that when energy disappears from the center of mass motion it may be converted into internal energy
    Hold the balls horizontally with the spring relaxed and drop; it should produce a high rebound. Then drop at an angle of about 45 degrees to the horizontal. The device will not rebound very high, but will develop a lot of internal energy, as evidenced by lots of spring vibration.

    This device can also be used as a simple model of energy in a two-atom molecule. Erik Neumann has created a simulation of this demonstration for this purpose as well. It can be found at https://www.myphysicslab.com/springs/molecule2-en.html .
    C8

  • C8-12: JUMPING MASSES WITH INTERNAL SPRINGS

    C8-12
    Demonstrate conversion of internal energy of a spring into kinetic energy and then gravitational potential energy.
    Set device so as to store energy in the spring by compressing or twisting the spring. Release rapidly or as required to allow conversion of energy stored in the spring into other forms.
    C8

  • C8-21: ROCK AND WASTE BASKET

    C8-21
    Demonstrate conservation of energy in a humorous way.
    Hold the rock up head high and drop it into the waste basket. Use the board to prevent damage to the floor. Have your students list all the possible types of work and energy involved, such as work done lifting the rock, gravitational potential energy, kinetic energy, heat, sound, and energy of deformation.
    OS1

  • C8-22: ENERGY CONVERSION - SUPERBALL AND SOUNDING BOARD

    C8-22
    Show transformation of energy from one form to another.
    Observe that the rebound of the superball is less when it is dropped on the metal shelving than when it is dropped onto a hard surface such as the floor. Discuss the possible forms of energy involved. Do the same experiment with a ping pong ball; describe and explain any differences.

  • C8-34: POWER - INSTRUCTOR DRAGGING CONCRETE BLOCK

    C8-34
    Demonstrate power
    Drag block with uniform speed and measure the force. Calculate the power from the force, the distance traveled, and the time elapsed.
    FS1, ME1

    c8-34a