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PHYS106

  • I3-19: LIFTING USING ATMOSPHERIC PRESSURE

    I3-19
    Dramatically demonstrate an effect of air pressure.
    A rubber cup with a molded handle is held in contact with some horizontal object like a wooden box (in photograph above) or a cart top. Pulling upward on the handle allows you to lift the object, due to the ability of atmospheric air pressure to hold the rubber sheet in contact with the surface.
    I3

    i3-19ai3 19

  • I4-02: PVT SURFACE - TRANSPARENT

    I4-02
    Illustrate aspects of phase transitions.
    This is a "generic" phase diagram on which the instructor can write details using various colors of felt tip pens. Projections can easily be seen, and the overall geometry can be observed because the model is transparent.

  • I4-31 ICE BOMB

    I4-31
    Demonstrates forces created by freezing water
    A pipe elbow with end caps is filled with water, sealed by tightening the ends, and dropped into a metal container of liquid nitrogen. Within about one minute the water freezes, expanding sufficiently to break the cast iron with a loud crack and a big cloud of vapor.
    I0, I4, SU5, OS6

  • I5-11 ADIABATIC PROCESS - AIR PISTON WITH THERMISTOR

    I5-11
    Demonstrates adiabatic compression and expansion of air
    A thermister is enclosed in a small cylinder of air, the volume of which can be rapidly changed by moving a piston up and down. Pushing the piston down compresses the air, the air heats and the temperature increases, producing an increase in the resistance of the thermistor. Pulling the piston up expands the air adiabatically, the air cools and the temperature decreases, producing a decrease in the resistance of the thermistor. The thermistor is identical to those used in the thermometer probes of the old commercial digital thermometer.
    I5, I0

  • I7-11: FERMI SURFACE OF ALUMINUM

    I7-11
    Illustrate the Fermi surface of aluminum.
    Model of Fermi surface of aluminum.
    I7

  • K8-01 ELECTROMAGNETIC WAVE - MODEL

    K8-01
    Shows the relationship between the electric and magnetic field vectors in a plane-polarized traveling electromagnetic wave
    Red pegs represent the electric field vector and blue pegs represent the magnetic vector. The spatial relationship between these vectors and the direction of propagation can be seen. By moving the model along its axis the temporal aspect of the wave can be shown. This wave has a wavelength of 0.81 meters, and as an EM wave would have a frequency of 370MHz
    FS1

  • K8-04: SPEED OF LIGHT

    K8-04
    Measure the speed of light

    A laser light pulse a few nanoseconds long is emitted by a light-emitting diode and immediately strikes a partially silvered mirror. The reflected light returns to a phototransistor to give the first pulse of the oscilloscope trace shown in the picture. The light transmitted through the partially silvered mirror reflects off a distant front-surface mirror, in the foreground of the picture, returning to the phototransistor to create the second pulse. The distance the laser beam travels, measured using a metric tape, and the elapsed time, determined from the oscilloscope trace, are used to calculate the speed of light.

    Please Note: Care must be used to position the light reflected from the distant mirror onto the phototransistor. This needs to be carefully monitored while in use, as environmental changes can affect it. Also, if there are issues of signal stability, check the trigger level on the oscilloscope to confirm that it is compatible with the trigger signal.

    K8, ME2

    K8-04A

  • K8-42: RADIOWAVES - ENERGY AND DIPOLE PATTERN

    K8-42
    Demonstrates transmission of energy in electromagnetic waves. Shows the radiation pattern of the dipole antenna

    This demonstration is centered on a simple radio transmitter with an antenna, which sends a signal to a handheld dipole antenna connected to a light bulb. The receiving antenna can be moved around in space, keeping the two antennas parallel, to observe the dipole radiation pattern. Rotating the receiving antenna to a vertical orientation shows that the radiowaves are polarized, as seen by the light going out.
    Background

    An antenna receives an induced current from the electromagnetic field of the passing wave. The dipole is a linearly polarized antenna, sensitive to signals oriented in a particular direction. In this experiment, we can see this dramatically, as changing the orientation of the antenna relative to the source produces a significant drop in signal strength, so that it is no longer receiving sufficient energy to light the bulb.

    Compare this effect to other wave and polarization demonstrations in sections G3 and M7.
    FS1

  • L2-05 PERVERTED IMAGE - AXES IN MIRROR

    L2-05
    Investigation of the nature of images from a plane mirror
    A plane mirror with three small coordinate axes, one left-handed and two right-handed. Position one right-handed coordinate system in front of the mirror and ask a student to line up the second right-handed coordinate system so that it looks like the image in the mirror. It will quickly be seen to be impossible. Try again with the left-handed coordinate system. That this can be done indicates that the mirror inverts one of the axes, but which one? Everyone agrees that the mirror does not invert top-to-bottom. Stand in front of the mirror and wiggle your right hand; the hand on the same side wiggles in the mirror, indicating no left-to-right inversion!
    L2, OS6

  • L2-06 MAGIC TRICK - DISAPPEARING RABBIT

    L2-06
    Plane-mirror magic trick


    A box has been divided diagonally by a flat mirror. A hatch in the top lets a toy rabbit be dropped in to the space behind the mirror.
    Engagement Suggestion
    • • The box is first shown to the group. Then the black cloth is placed over the front of the box, the trap door on top of the box opened, and the rabbit put into the box through the trap door.
    • • Invite students to predict what they will see when the cloth is removed.
    • • When the black cloth is removed the rabbit has vanished into thin air (behind the mirror).
    • • Challenge then to analyze how this has happened
    • • Explain the positioning of the mirror, and invite them to consider what it would look like with the mirror at different angles.
    Background
    Because the mirror is mounted at a 45 degree angle, it reflects the bottom of the box to look like the rear of the box. So viewed from the front, the box appears empty. This is a common technique for creating such illusions.
    L2

  • L2-24: PARTIALLY SILVERED CYLINDER

    L2-24
    Demonstrate Partially Silvered Surfaces
    A small clear light bulb is placed in a plastic cylinder which is covered with a half-silvered aluminized mylar sheet. When the light is off, the outside is brighter and the light bulb cannot be seen. When the light is on, the glowing filament can easily be seen through the aluminized mylar.
    L2

  • L2-27: Infinity Mirror - Portable

    L2-27
    Illusion with half-silvered mirror.

    This is a smaller, more easily portable version of demonstration L2-22, suitable for use in small classrooms. A ring of lights is repeatedly reflected by a rear mirror and a partially silvered front window, creating the illusion of lights vanishing into the distance.
    L2

    L2-27: mirror device illuminated on table, showing shallow housing for lights behind mirrored face

  • L2-44: CORNER REFLECTOR - HAND HELD

    L2-44
    Demonstrate dramatically how a corner reflector works.

    The laser is mounted on a stand with the beam coming out a hole in the white baffle, and aimed across the room or to the rear of the lecture hall. Hold the corner reflector in the beam and the reflected beam will return to be easily seen on the white card. Rotate the corner reflector and change its angle, showing that the beam still returns to the card. The specular reflection of the laser beam off the front surface of the glass will also be seen moving around the room.

    Background:

    This mirror element is of the type used to construct the reflector for the lunar ranging experiment, you can read more at TERP: Mirrors on the Moon and Big Think: We Use Lasers To Keep Track Of The Moon.

    L2, FS1

    l2-44

  • L2-61: MIRROR TILES WITH LIGHT BULB

    L2-61
    Show multiple reflections using two mirrors
    Two hinged mirror tiles are positioned at an acute angle with a single light bulb between them. The succession of images makes it appear that there are many more bulbs, with the exact number dependent on the angle between the two mirror tiles.

    geo

  • L3-03 LARGE CONVEX MIRROR (60cm)

    L3-03
    Shows the image from a convex mirror
    Just observe your image in the mirror. Note that this type of mirror is used in stores, school buses, and other commercial applications. Because it produces an erect and small image, it can be used as the right hand rear view mirror in a car to see over several lanes of traffic. Because the image is smaller and therefore looks farther away, rear view mirrors carry the warning "Objects in this mirror are closer than they appear."
    OS8

  • L3-16 FOCUSING OF HEAT WAVES BY MIRRORS

    L3-16
    Demonstrates that concave mirrors can focus heat waves
    Two parabolic concave mirrors are used to focus heat from a nichrome heater and light a match.
    L3, PW1

  • L3-19 PENNY AND PARABOLIC MIRRORS

    L3-19
    Classic illusion of penny levitating above a pair of parabolic concave mirrors
    This commercial apparatus forms a real image of a penny glued to the bottom mirror. Two concave parabolic mirrors with the correct focal length and spacing create an image of the penny levitating on the opening of the upper mirror. The illusion can be viewed within a limited angle, so it is most effective for individual observation. A ray drawing is included which shows how the image is produced.

    Invite students to place their hand through the image, to get a feel (or not) for what's happening. Have them consider where such images might be used.
    L3

  • L3-31 GIANT 160cm MIRROR - CONCAVE AND CONVEX

    L3-31
    Demonstrates images from concave and convex mirrors
    This five-foot diameter, 132cm (252-inch) radius of curvature parabolic mirror was originally designed as a solar collector on a satellite. Both convex and concave sides can be used with large classes or individually.

    Students can stand in front of the concave side at different distances to find the focal point. Invite students to predict the orientation of the image they see at different points, then try it out.
    FS0

  • L4-01 OPTICAL BOARD - RECTANGULAR SLAB

    L4-01
    Demonstrates refraction. Shows displacement of rays in a uniform slab of glass
    A slit baffle with concave and convex mirrors are used to produce a beam of parallel rays of light. A rectangular slab of lucite placed at an angle in the rays of light produces refraction at each surface, leading to displacement of the light rays. The central ray in the picture is reflected internally off the end surface of the slab and directed upward.
    FS0

  • L4-02 REFRACTION - BEER MUG IN WATER

    L4-02
    Illustrates refraction
    Due to refraction of the light at the walls of the mug, the mug looks like it has very thin walls and is really filled with liquid. When the mug is placed into water, as in the photograph, the real situation becomes apparent: the mug has very thick glass walls, and holds much less liquid than you think