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PHYS260

  • F1-01 FLUID PRESSURE VS. DEPTH

    F1-01
    Demonstrates that fluid pressure increases linearly with depth and is isotropic.
    An L-shaped glass tube connected to a liquid manometer is inserted into a tank of water. The pressure in the water tank can be measured at any depth. Holding the tube at a particular depth and rotating it about the end will show no change in pressure, demonstrating that pressure is isotropic.
    F1, FS2

  • F1-02: FLUID PRESSURE VS DEPTH - ANEROID GAUGE

    F1-02
    Show water pressure versus depth with an aneroid gauge.
    An L-shaped glass tube, connected to an aneroid gauge, is immersed in water. The pressure at any depth is indicated directly on the gauge. This enables students to see the pressure at any level.

    Invite students to make predictions about the relationship between depth and pressure, and perhaps even sketch what they expect the graph of this relationship to look like. Then take a few data points and see what happens.
    F1

  • F1-04: EQUILIBRIUM TUBES

    F1-04
    Demonstrate that pressure is transmitted equally throughout a fluid.
    By raising and lowering the reservoir, one can show that the water level in all three vases will rise and fall together. From this one concludes that pressure is transmitted uniformly throughout the water.
    F1

  • F1-05: DOES WATER SEEK ITS OWN LEVEL?

    F1-05
    A trick to challenge the students.

    The liquid level in the left side of the U-tube is higher than that in the right side of the U-tube. How does one explain this?

    Two immiscible fluids of different density which are identical in physical appearance are in the two ends of the U-tube. The point where they meet (which could be easily seen) is covered by the clamp which holds the U-tube.

  • F1-06 WATER SEEKS ITS OWN LEVEL

    F1-06
    Shows that pressure is dependent on depth, not shape of container

    This set of conjoined glass tubes is filled with green-dyed water. The water level in the four different tubes is the same even though the volumes and shapes of the tubes are very different.

    Engagement Suggestion
    • For advanced students, consider tilting the tubes slightly, then plugging them with corks so that the different amounts of trapped air cause the water to be at different levels. Challenge students to analyze why this changes the results, then remove the corks to show what happens.
    Background

    This illustrates that the pressure in an open container of liquid is dependent only on the depth, not the shape or area.

  • F2-01 ARCHIMEDES' PRINCIPLE

    F2-01
    Demonstrates the buoyant force on a body submerged in a fluid to be equal to the weight of the displaced fluid.
    Hanging from the balance are a hollow can and a solid cylindrical metal block of the same volume V. Lowering the metal block into a beaker of water results in a buoyant force equal to the weight of a volume V of water. Pouring the volume V of water into the can restores the original weight as read on the spring scale.
    FS2

  • F2-04: BUOYANCY - SPHERE AND WATER

    F2-04
    Challenge the students' thinking about the buoyant force by considering the question: "Will a round object, without a flat top and bottom surface, experience a buoyant force, as does a cylinder?"
    A round steel ball and a hollow metal can hang from the scale. The pressure is always normal to the surface of a body and increases linearly as the depth increases. When the steel ball is immersed it too experiences a buoyant force, because the upward vertical component of pressure applied to the lower hemisphere is greater in magnitude than the downward vertical component of the pressure exerted on the upper hemisphere.

    f2-04a

  • F2-05 BUOYANCY - BOAT AND ROCK

    F2-05
    Illustrates buoyancy
    Boat and rock float in a closed pond. removing rock from boat and dropping it in pond will cause the water level of the pond to go down
    F2

  • F2-06: BUOYANCY - SINKING BOAT

    F2-06
    Illustrates buoyancy
    A heavy copper "boat" floats in a fish tank "pond," as seen in the photograph at the left. The water level in the pond is marked by the top of the black tape on either side of the tank. A cork is removed from a hole in the bottom of the boat, allowing the boat to fill with water and sink. As the boat sinks, the water level in the pond goes down

  • F2-07: BUOYANCY - PEPSI AND DIET PEPSI

    F2-07
    Show the difference in density between soft drinks with and without sugar.
    Unopened cans of Pepsi and Diet Pepsi are floated in water. The Pepsi sinks, while the Diet Pepsi floats. The density of the Pepsi is increased by the dissolved sugar, which occupies space between the water molecules. Diet Pepsi has no additional sugar, and is therefore less dense.

  • F2-21 REACTION TO BUOYANT FORCE

    F2-21
    Demonstrates the reaction force using a liquid.
    A beaker of water is balanced by two brass weights. Stick your finger into the water about up to the first knuckle, the water side will go down. The water exerts a buoyant force on your finger, so your finger exerts a reaction to the buoyant force on the water, thereby causing the water side to go down.
    F2, ME1

  • F2-23: BUOYANCY PARADOX - INVERTED BLOCK

    F2-23
    Illustrate buoyancy in a paradoxical way.
    A large styrofoam block with a smaller aluminum block mounted on top as in the picture at the left, floats with the center of the styrofoam block, marked by the black line, at the water level. Q: When this object is inverted, with the aluminum block in the water, will the water level on the styrofoam block be (a) above, (b) below, or (c) at the black line?

    A: The water level will be below the black line, as seen by clicking your mouse on either of the pictures above. Notice also that the water level in the tank remains the same, at the level of the top of the black tape.

    f2-23af2-23b

  • F4-11: LAMINAR AND TURBULENT FLOW OF AIR

    F4-11
    Demonstrate laminar and turbulent flow.
    Place the streamers near the front of the fan, and notice that they line up due to the laminar flow. Then place the streamers behind the fan or about one meter away, and note that they move irregularly due to the turbulent flow.
    F4, OS6

    f4-11a

  • F5-12: BERNOULLI'S PRINCIPLE?

    F5-12
    Stimulate discussion of Bernoulli's principle and common misconceptions surrounding its application.
    A water reservoir has four chimneys, each topped with a different surface. A stream of air moving over the concave flange (at left, above and below) causes the water level to go down. This is the result of the centripital force required to make the air move in a curved path along the flange. Air moving over the convex flange (left center) causes the water level to rise. This is a result of the Coanda effect, wherein the airflow "sticks" to the surface with the corresponding reaction force causing a decrease in the air pressure in the tube. Moving air flowing over the flat flange (at right) has no noticeable effect. Moving air flowing over a naked end of the the tube results in a lower pressure, causing the water to rise in the tube.

    f5-12df5-12af5-12bf5-12c

  • F5-21 VENTURI TUBE WITH MANOMETERS

    F5-21
    Illustrates the venturi effect
    Turn on the blower and slowly move it so that it directs some air into the venturi tube device. The higher water level indicates less air pressure in that tube.

  • F5-22 VENTURI TUBE WITH PING PONG BALLS

    F5-22
    Illustrates the venturi effect.
    In this Venturi tube the levitation of the ping pong balls in an airstream is used as a pressure sensor; the higher the ball the greater the pressure of the air coming from that hole. Both the venturi effect and the reduction of pressure along the tube can be seen.

  • G1-01 EXAMPLES OF SIMPLE HARMONIC MOTION

    G1-01
    Illustrates simple harmonic motion

    This demonstration lets you compare three typical pendula: a simple pendulum (mass on string), a physical pendulum (swinging rod), and a mass on a spring. Any of these produce simple harmonic motion, with a variety of periods. Useful for showing that the same equation describes the motion of any type of oscillating body.
    You can also compare these real-world pendula with some simulated ones:
    1. Erik Neumann's Single Spring simulation
    2. Erik Neumann's Pendulum simulation
    3. PhET Masses on Springs
    4. PhET Pendulum Lab
    FS2

  • G1-11 COMPARISON OF SHM AND UCM

    G1-11
    Demonstrates the relationship between simple harmonic motion and uniform circular motion.
    Turning a crank on the rear of the apparatus causes the center ball to move in circular motion around a 30cm diameter orbit, while the ball on top executes simple harmonic motion. It can be seen that SHM is the projection of UCM. This device can also be used to discuss the concept of degrees of motion in SHM by comparison with the reference circle.

  • G1-14 PENDULA WITH DIFFERENT MASSES

    G1-14
    Demonstrates independence of a simple pendulum's period with mass of the bob.
    Four geometrically identical pendula have bobs made from lead, brass, stainless steel, and aluminum, respectively. Their periods are the same.
    FS2

  • G1-15 PENDULA WITH 4 TO 1 LENGTH RATIO

    G1-15
    Shows that period of a simple pendulum is proportional to the square root of its length
    The two pendula are started in phase. The shorter pendulum undergoes two complete oscillations for each oscillation of the longer pendulum.
    FS2