Do-It-Yourself Science Experiments

These science experiments are perfect for kids who need intellectual stimulation combined with action—plus, we've included explanations for parents.

96. EGG IN A BOTTLE: Drop three lit matches into a glass bottle (ideally, an old-fashioned milk bottle) and immediately placed a peeled, hard-boiled egg on the mouth of the bottle. Is it magic?

Why does the egg fall into the bottle?
The flames heat the air, which then expands and (some of it) escapes. As the matches go out, the air cools and contracts, causing the pressure inside the bottle to be greater than the pressure outside the bottle. The pressure difference causes the egg to drop into the bottle.

97. ALKA-SELTZER ROCKETS: Place one tablespoon vinegar and half an Alka-Seltzer tablet inside a film canister (a clear canister with a secure lid is best.) Close the lid, making sure that it fits tightly inside the canister. Stand back and prepare for blastoff!

Why does the canister fly to the ceiling?
The Alka-Seltzer combined with the vinegar causes a chemical reaction that releases carbon dioxide gas which builds up pressure and drives the rocket.

98. SWIMMING RAISINS: Drop three raisins into a glass bottle filled halfway with bubbly (carbonated) water. Wait and watch.

Why do the raisins rise then fall?
Bubbly water contains dissolved carbon dioxide gas that collects on the bumpy surface of the raisins, carrying them to the surface where the gas is released into the air, causing them to sink again.

99. GEYSER ERUPTION: Unrwap a roll of Mentos. The goal is to drop as many as possible into a half-liter bottle of Coke at one time (harder than it sounds) and then get out of the way as fast as possible. Be prepared for a major eruption and some sticky cleanup.

Why does the soda become a jet stream?
As with the raisins, the carbon dioxide gas collects on the surface of the Mentos. But the Mentos are heavier than the raisins, so they sink to the bottom of the bottle, then blast upwards.

100. MAGNETIC PULL: Draw a maze on a piece of cardboard. Place a paperclip on top of the cardboard and put a magnet under the cardboard in the same spot as the paperclip. Try to move the paperclip through the maze without touching it.

Now, drop the paperclip in a glass of water. Place the magnet outside the glass (near the paperclip) and try to guide the paperclip to the top without it getting wet.

Why does the magnet pull the paperclip?
Magnets pull on things like iron and steel (magnetic materials) but pull through things like cardboard, glass and plastic (nonmagnetic things.)

101. VOLCANO ERUPTION: This oldie but goodie requires a bit of prep work. Make a volcano (out of cardboard, papier-mâché, or clay.) Fill a cup with baking soda and place it inside the volcano. Fill a bottle with vinegar, a few drops of food coloring (for oohs and ahhs), and a few drops of liquid soap. Pour the liquid into the baking-soda cup.

Why does the volcano erupt?
The vinegar reacts with the baking soda, causing the explosion.