Individual Reflection Ping Pong Ball Exercise - Tan Wan Ting Malissa

My role in this ping pong ball exercise was to help think of ideas, prepare the materials and help my group members execute out the exercise.

Initially, the teacher told us to make use of a pair of scissors, a roll of scotch tape, a balloon, a ping pong ball and two pieces of paper to blow the ping pong ball as high as possible. The most workable idea that came to my mind was to make use of the thrust of the air from the balloon to push the ping pong ball up.

Using this idea, we thought of how to make use of the materials we are given and proceeded to create the props. We used a piece of A4 paper and rolled it along its length to create a cylinder and used a tape to tape it. One of my teammates then blowed up the balloon and attached it to one end of the A4 paper. We placed the ping pong ball at the other end and slowly release the mouth of the balloon to release the air from it. The ping pong ball floated only at a very low height.

Our teacher's suggestion was to make the cylinder shorter so that the air would be able to reach the ping pong ball faster and would not lose its speed that fast. I thought of another way to roll the piece of A4 paper which was to roll it into a cone shape. But, after further consideration, i realized that by rolling it into a cone, the hole at one end would be smaller and the air going through it will be slow and little. Whereas for the other end, the hole would be much bigger and air will be lost easily and quickly. So, we decided to continue improving on the size and length of the A4 cylinder paper. We tried another way by making the cylinder short and thin and it worked. The ping pong ball flew much higher than before and it was floating quite stably in the air.

After all the experimenting, this exercise has made me realize that a shorter and thinner cylinder allow the air to diffuse faster from the balloon to the empty space inside the cylinder. As compared to the amount of air inside the balloon, the amount of air in the thin and short cylinder would be very little, hence diffusion will occur.