Egg Into Bottle

Find a glass bottle that has a mouth slightly smaller in diameter than an egg. Pour some hot water into the bottle (be careful!), shake it vigorously and empty the water.

Peel a soft-boiled egg and place it on the mouth of the bottle. Leave it there for a while and it will get sucked inside.

The vapor from the hot water drives the air out of the bottle. Once the egg seals the top of the bottle, the air can’t get back in. As the water vapor cools, it turns back into water, causing the pressure inside the bottle to drop. The higher pressure of the outside air pushes the egg into the bottle.

A Candle That Sucks Water

Place a candle upright in the middle of a saucer. Fill the saucer with water. Light the candle. Place a glass over the candle. When the flame goes out, the water in the saucer will get sucked into the glass.

How Does It Work?

When the candle is burning inside the glass, the heat makes the air expand, so some of the air escapes outside the glass. The candle goes out after it uses up all the oxygen, so the air inside the glass cools. As it cools, the pressure inside the glass drops. Some of the carbon dioxide formed by the flame dissolves in the water as well, decreasing the pressure even more. The water outside the glass on the saucer is forced into the glass by the higher aire pressure outside.

A Can That Can “Walk”

Place an empty aluminum can on its side on the floor. Blow up a balloon and tie a knot in the end. Rub a tissue back and forth on the balloon.

When you put the balloon near the can, the can will start rolling toward the balloon.

How Does It Work?

When you rub the balloon with a tissue, the balloon gets a negative electric charge of several thousand volts. When you put the balloon near the can, electrostatic induction affects the molecules in the metal. The outside of the can gets a positive charge, so it is drawn toward the balloon and starts rolling in that direction.

Keeping Water Separate

Fill two identical glasses with water. Add two tablespoons of salt to the water in one glass and stir well. Add a few drops of food coloring to the water in the other glass.

Cover the glass containing the colored water with a sheet of paper, turn it upside down and place it on top of the glass containing salt water. (Be sure to do this trick over a saucer or bowl.)

Gently pull the paper out from between the glasses. The colored water and the salt water will remain separate.

How Does It Work?

Salt water is heavier than colored water, so the two stay separate as long as the boundary between them isn’t disturbed. Try turning the two glasses over, though. The heavier salt water will now be on top, so it will flow down and mix with the colored water.

Floating Arm

Stand next to a wall with one arm pressing against the wall. Push your arm against the wall as if you're trying to move the wall. Don't push with your body, only push with your arm. Count to 20 as you push your arm against the wall.
Now step away from the wall and let your arms hang relaxed at your sides. Your arm will "magically" start to rise into the air by itself!

Soap Rainbows

Here's how to make soap rainbows with your hands! First get your hands good and soapy over the sink. Then place your palms together. Pull your hands slowly apart. Make sure that your thumbs and index fingers don't lose contact with each other. Check out the cool swirling colors!

Bubbles with Your Hands

Here's how to make huge soap bubbles with your hands! First get your hands good and soapy over the sink. Then make an "OK" sign with your fingers, but curl your index finger all the way in towards your hand.
Now slide your index finger out towards the tip of your thumb. Make sure that your index finger stays in contact with your thumb! Now you should have a film of soap between your index finger and thumb.
Take a deep breath, then blow into the film of soap to make a bubble. It might take practice to get it to work! We have found that it helps if you have plenty of water on your hand, and hold your hand close to your mouth.

Toothpick Torpedo

Dab a little shampoo on the blunt end of a wooden toothpick.

Drop the toothpick in a pan of water. The toothpick will start moving in the direction of the sharp end.

Shampoo contains agents that reduce the surface tension of liquids. As the shampoo on the end of the toothpick dissolves, it reduces the water’s surface tension around it, thus releasing the water’s hold on that end of the toothpick. The water around the other end of the toothpick still has surface tension, so it pulls the toothpick in that direction.

Reading Through an Envelope

With a black felt-tip pen, write a three-letter word in large letters on a white piece of paper. Place the paper in a brown envelope, and insert that envelope into a white envelope. The writing on the paper should now be impossible to read.

Get a piece of dark construction paper or tear out a page from a magazine that is printed on both sides. Roll up the paper into a four-inch-long tube. When you hold the tube against the envelope, you’ll be able to read the writing inside.

Usually you can’t read the writing inside an envelope because of the light reflected off the envelope’s white surface. But the tube blocks that reflected light, so you see only the light coming through the envelope.