Try these experiments and observe what happens. Guess why it happens and compare your results to those on the back of the page. Now you can try Newton's Apple experiments at home!
Find a small-necked, corked bottle and balance an ice cube on top of it. Cut a 15-inch piece of thin, strong wire and tie a hammer to each end. Balance the wire across the middle of the ice cube. What do you think will happen? Try it!
Tie one end of a long piece of string to the middle of a matchstick. Pull the other end of the string up through the hole in the center of an LP record (so the matchstick is centered underneath the hole). Try to swing the record back and forth like a pendulum in smooth, even movements. Now give the record a spin. What will happen when you try to swing the record again? Try it!
Poke a hole in the bottom left hand corner of each of the four faces of a half-gallon, paper milk carton. Poke an additional hole in the top flap of the carton and tie a string through it. Suspend the carton from the string. Cover the holes with your fingers and pour water into the carton. What will happen when you remove your fingers from the holes? Try it!
Carefully break off the small end of four eggs and pour out the insides. Wind a piece of cellophane tape around the center of each eggshell. Cut through the center of the tape to make four dome-shaped shells (discard the broken end of each shell). Lay the four domes on a table with the cut sides down arranged in the shape of a rectangle. Next, guess how many telephone books you can lay on top of the shells before they break. Try it!
Light a candle and hold a cylindrical container in front of it (e.g. small oatmeal or salt package). Take a deep breath and blow against the other side of the container, keeping your mouth even with the flame of the candle. Can you blow out the candle? Try it!
Using a nail, make five holes in the side of an aluminum can. The holes should be made close to the base of the can and should be spaced 1/4" apart. Hold the can under a kitchen faucet or hose and fill it with water. Pinch the streams of water together with your thumb and forefinger. What happens?
How can the wire cut right through the ice cube without breaking it into two pieces? The pressure of the wire causes the ice to melt beneath it. The wire sinks easily through the melted ice, while the ice above the wire, which is no longer subjected to pressure, refreezes. This scientific principle also applies to ice skating. The pressure that your skates exert on ice causes a layer of water to form under the blades, creating a slick and slippery surface for sliding.
What happens to the carton? Newton's Third Law states that every action has an equal and opposite reaction. Water shoots out the holes, and pushes back on the carton with equal force. A turbine is formed as the energy of the moving liquid is converted into rotational energy.
What makes the record swing smoothly? Gyroscopic inertia is the property of a rotating object to resist any force which would change its axis of rotation. Once the record is set spinning at an angle perpendicular to the string, it will resist any forces (such as gravity) that try to change that angle.
How can fragile egg shells support heavy books? Arches--even those made of eggshells--are strong because they exert horizontal as well as vertical forces to resist the pressure of heavy loads. The crown of an eggshell can support heavy books because the weight is distributed evenly along the structure of the egg.
Why are you able to blow the candle out? The Coanda Effect is the tendency of a fluid to follow the wall contour of a curved surface. In this case, air acts like a fluid and follows the contour of the round container. When the streams meet on the other side, they combine to blow out the candle.
Why do the streams knot together? The streams of water are held together by the water's "stickiness," or surface tension. Surface tension is the tendency of the surface of a liquid to behave as though covered with a skin. This is due to the cohesive forces between the molecules at and near the surface.