Energy transfer

Today, P came back home and was very excited. When I enquired about her excitement , she said "Today, we played games at school and I feel very energetic. So, tell me what experiments are we doing for the science activities". Till then I was not sure of the topic and so was still wondering what kind of activities to do. But, the word "energetic" gave me the idea of doing some experiments related to energy transfer. That's how it all started.


We have  heard the word 'energy' quite a few times. But, let's see what it really means in physics.

What is Energy?

Energy is the measurement of the ability of something  to do any work.  It is not a material substance. Energy exists in many different forms such as light energy, mechanical energy, heat energy, sound energy, chemical energy, nuclear energy and so on.

Though we hear so much about energy consumption, energy can never be created or destroyed. It can only be transferred from one form to the other while work is being done.

So, here is an experiment that helps us to understand how energy is transferred using the catapult which had more usage during medieval times.


Materials needed

1. Eight craft sticks (popsicle sticks)
2. Four or five sturdy rubber bands
3. Glue
4. Plastic bottle cap to hold a cotton ball
5. Cotton ball (or  you can make a small ball by crumbling some paper.)
6. Small open area ( It should be a sturdy, flat surface such as a table or floor.) 

 Procedure

1. Take six craft sticks, stack them one on top of the other. By wrapping rubber bands around both ends of the stack you can secure them together

 2. Take the remaining 2 popsicle sticks and wrap them together at one end and attach it perpendicular to the stack that you just made. Wrap a rubber band in a X shape to secure it tightly in the middle. If you cross it this way, the sticks will stay nicely perpendicular.

1. Glue a bottle cap to the stick that is on the top. This is the launching pad  for the catapult. 
2. Wait for the glue to stick. 
3. Put your catapult in a open, flat, sturdy area. 
   
4. 
   
5. Place a cotton ball in the launching cup and press a lit bit to let it go. 
6. You might need to repeat the test few times to make your observations.
   

Did you notice that your cotton ball flew higher when you pushed harder?
When you bend your stick by pushing it you are transferring potential energy which in turn when released becomes the energy in motion (kinetic energy). Bending farther means transfer of more elastic potential energy to the stick  which then makes the cotton ball fly higher and further.

Variations

To make it as an experiment, try changing one variable in this.

1. Use different  materials such as cotton ball, paper ball, peanut, marshmallow.

2. Change the angles of projectile by moving the six sticks closer to the launching pad and  check if your ball flies higher?

We also made different types of catapults using spoon, as the launching pad and also tried using a stapler for variation.