Hold up a ball of clay about the size of a ping pong ball and ask students if they think it will sink or float in water. Place the clay in the water. Do you think that if I use ½-the amount of clay ...

These “moss balls” are popular pets in Japan ... and in graduated cylinders in the lab. But why do they float in the daytime and sink at night? A newly published paper by Dora Cano-Ramirez ...

Some objects float in water and other sink. But did you know that you can change whether something floats or sinks by adding a substance to the water? Let's try it and see! Pour water into a cup until ...