Collisions

Before Video

• Energy makes things happen. (Or more formally: energy is the ability to do work.) It is important to remember that energy is not “stuff.” It cannot be held in your hand or weighed.

• The basic definition of a collision is when one object runs into another. During collisions energy is transferred from one object to another.

• Yes. For an object to be in motion, energy must be transferred to it.

• Yes. The moving bat is colliding with the ball and transferring energy from the moving bat to the ball.

After Video

• False. People use energy to make things happen, such as lifting weight, but it's not just people that use energy. Water uses energy to turn a water wheel, wind use energy to spin wind turbines and animals use energy when running or butting heads.

• The weight drops the top ramp, which collides with the metal ball. The metal ball rolls down a series of ramps and collides with a rod that releases the spinning circle. The spinning circle travels down as it spins, which eventually pulls the large hanging metal ball loose. The ball drops slowly as it unwinds, turning the windmill. That eventually pulls a pin holding the ice. The ice slides down the tube and drops into the pitcher. During each collision energy is transferred between objects.

• At the moment the bat touches the ball, energy from the moving bat is transferred to the ball, setting it in motion.

• In the video we observe a baseball flying after the bat hits it, the chain reaction of motion during the Rube Goldberg machine demonstration and Izzy flying back after Dr. Jeff’s Mom collides with him.

• When hit with more speed, Izzy flies back farther.

• The energy of motion from the swinging drum stick is transferred to the gong, which then vibrates producing sound.

• Specially designed plexiglass sheets surround hockey rinks to keep fans from being hit by a flying puck. The energy from the puck is transferred into motion as the plexiglass bends and moves. Some of the energy also becomes sound and heat.

• Dr. Jeff demonstrates how a hole is burned through a sheet of flash paper when two metal balls collide with the paper between them. The motion energy of the balls is transferred into sound and heat.