The shadow cast by a high-flying object, such as an airplane, is about the same size as the object itself, no matter how high it is flying. It may appear bigger than the object in late afternoon or early morning, due to the angle of the sun (and thus the shadow) to the ground.

The metal lithium will float on water.

A photon of visible light is about three feet long.

Iron, boron, nickel, cobalt, and neodynium are the only elements that can be magnetic. All magnets must contain an alloy of these.

All energy used by living cells comes from the chemical compound adenosine triphosphate (ATP). Food and sunlight energy are converted into this form by every living thing we know of.

Water is most dense at temperatures between 0 and 4 degrees centigrade.

Waves can go around corners.

Humidity in the air is measured relative to the amount of moisture that the air could hold at its current temperature and pressure.

Bacteria and algae are neither animals nor plants; they are classified as monera (cells lacking a nucleus).

Warm air can hold more moisture than cold air can.

Ethanol is the alcohol in alcoholic beverages.