Ask your students why this should happen? The mass has increased, but why does that change how it balances?

The water moves when the can tilts, causing the center of mass to shift – with just the right amount of water, the new center of mass will be above the edge of the can, and so it will balance.

Some cans will tend towards a particular orientation and will roll along the edge to that point, displaying a damped oscillation – invite students to hypothesize why this is.

A rope is tied to a tennis ball at one end, and to a brick at the other. The rope runs loosely through a plastic handle, allowing it to slide freely.

Spin the ball on its rope around in a circle above your head. As the radius of rotation increases, the centripetal acceleration does as well, increasing the force acting on the brick. At a certain point, the force will be sufficient to lift the brick off the table!

Check out further discussion of this demonstration, and a full mathematical treatment, at the link below!

Note: Use water no hotter than 90C. Do not expose to open flame, and do not apply water or heat to the liquid crystal strips, and keep them out of direct sunlight.

A pair of wooden frames can hold a collection of hexagonal objects. When shaken, the objects gradually form into a hexagonal grid, conforming the the container.

One of the frames has a few additional hexagons fixed to the base; try comparing the time/work required to form a lattice with or without these seeding points.

Donated by Dr. Stephen Parks.

This is an illustration of the diamagnetic and magnetic pinning effects of a superconducting material. When setting up, be sure to chill the puck in the position you want it above the track for maximum efficiency.

The University of Cambridge has made available a helpful video lecture on magnetic pinning: https://ascg.msm.cam.ac.uk/lectures/fundamentals/pinning.php.

Place a dry, empty aluminum soda can on the table. Build up a charge on one of the charging rods and hold it alongside the can, and you should see the can move slightly towards the rod; with a strong enough charge, you can pull the can across the table via the attraction to the rod. The charge on the rod is inducing an opposite charge on the side of the can.

Now, pick up the can, and ask the students to predict what will happen if you do the same thing with the other rod and an opposite charge. Poll them for their predictions, and the reasons behind them. Then put the can down and perform the experiment again with the other rod; you should see the same behaviour. Invite the students to discuss why this happened. The can was grounded when you picked it up, and retains no net charge on any side; the induction process is the same as before.

Note that this is the same effect that causes the ground sphere to slowly lean towards the Van de Graaff generator before a spark forms in demonstration J2-03.

Invite students to predict how the interaction will change when you change the polarity. Or, for advanced students, approach it from the other direction: Before powering it on, only tell them which direction the current flows, and invite them to predict the direction of motion. (We recommend testing this in private first to make sure your own prediction is correct.)

Note that this is a fairly large demonstration and requires some time to set up. P1-11 is recommended for smaller spaces.

Since we cannot easily create a long duration microgravity environment in the classroom, this demonstration instead models this effect with the expansion being caused by a change in air pressure. A column of discs is separated by marshmallows, and the whole placed into a vacuum chamber. As the pressure is reduced, the gas in the marshmallows expands, forcing apart the spinal discs. When pressure returns, the spine collapses back, much like astronauts experience when they return to Earth.

Challenge your students to think of other body parts and processes that could be similarly affected by changes in gravity.