Turn an old CD into a spectroscope to analyze light.

Make a conductivity meter and let your electrolytes shine.

Build an electroscope to detect electrical charge using straws.

Construct a simple hydrometer to compare the densities of solutions.

Dark-colored materials absorb and emit energy more readily than light-colored materials.

Make a record player with a pencil, pin, and paper.

Measure the height of an object indirectly using your hand and a ratio.

Find the height of a tree, paper rocket or North Star.

Break water into hydrogen and oxygen with a simple device.

Build a simple wind generator.

Make a balance that weighs very light things.

Measure the thickness of a sheet of paper.