Physics Project Making a parachute

Content Title Materials used Design Application of physics principles Results of experiment Conclusion and discussion Comments of group members Group list

Materials used Ice-cream box*1 Model wheels*4 Tissue roll*1 Sponges*4 Fishing lines*1 packet Plastic bags*2 Egg*1

Design

Application of physics principles We apply the Newton’s Second Law. It states that the acceleration of an object is directly proportional to, and in the same direction as, the net force acting on it, and inversely proportional to the mass of the object. As the purpose of this experiment is to make the parachute falling more slowly, we suggest to use a plastic bag to increase the air resistance so as to decrease the landing speed.

Application of physics principles At first, the object will accelerate (i.e. velocity increase). As it gains speed, the fluid friction increases (i.e. air resistance is directly proportional to velocity). Applying the formular F =ma, F = Weight – Air Resistance When weight is equal to air resistance, the net force is equal to 0 (i.e. acceleration =0).

Application of physics principles

Results of experiment Mass of the parachute: 0.1222 kg Average time taken: 5.09s Trial 1st 2nd 3rd Time taken/s 5.06 5.16

Conclusion and discussion After the competition, we find that we should add more plastic bags to increase the air resistance so as to reduce the speed of the parachute. In so doing we can ensure that the time the parachute took to travel to be longer. Besides, we are very happy as the egg didn’t break during this falling. Also, the appearance of this parachute helps to improve the performance of the parachute.

Comment of group members Chan Kai Yik 4E (21) This is the first time I make a parachute, and it has a lot of fun. This project lets me know more about how air resistance is related to our daily life. Although, we are not the best in this competition, the experience is still very exciting and fantastic. I think we can do better next time. For example, the appearance and the packaging can be improved and the landing speed of the parachute can be reduced.

Comment of group members Chu Ming Kin 4E (23) I really learn something from this project, especially the theory about parachute, for instant, the surface of the parachute can be made dome-like, so that it can increase air resistance. Moreover, my egg did not break since the air resistance is large enough to reduce the landing speed, and the materials wrapping the egg can protect it. Furthermore, the time of travel is long enough and the appearance of the parachute is fairly good. If we can do one more time, l will try to increase the surface area of the parachute because it has some problem this time. Also, my partners did their job quite well and handed in their product on time.

Comment of group members Lau Ka Wai 4E (28) At first I thought it is easy to make the parachute. However when we made the parachute, we want to use some materials but it was difficult to get the materials. Also, we waste some money to buy the ice-cream so as to use the container as the material for the parachute. Furthermore, we assumed the one that falling faster is the winner and we should be careful next time. Also, one of our team members is good at drawing. So, in the design of the parachute, it is easy to finish it.

Comment of group members Li Hok Fung 4E (31) When I knew that I had to make a parachute, an idea suddenly came upon my mind. I wanted to use a plastic bag to be the upper part and an ice-cream cup to be the container of the egg. Also, I wanted to draw some pictures on the bag and placed 4 sponges at the bottom of the cup to reduce impact force. I thought that would work and it might protect the egg. After I have made this parachute, I tried it as soon as possible. Although it could protect the egg, the landing velocity of it onto the floor was too high. I though lots of methods to improve it, but it didn’t work. So, I asked my group members to solve it with me. Finally, although it didn’t reach my expectation, it is an unforgettable memory for me. It leads me to the road of active learning.

Comment of group members Howard Ng 4E (36) It is my first time to design a parachute. For the very first step we had already decided to use some light materials, like sponges and ice cream box because we thought that the heavy materials might increase the weight of the parachute (since F=ma), then it may fall down quickly. However, when our parachute was being tested, the parachute reached the ground fast. We were shocked, because we thought that our parachute was perfect except the look was ugly. Have a look at other group’s parachutes and after having some discussion, we found that our parachute is too small! It is not large enough to do work against the air resistance. We should use a rubbish bag. Luckily, the egg inside the ice cream box did not break, because there were many sponges covering the egg.

Overall comments of group members I think this project is good for us. It can help me to know more about physics and we found that teamwork is important. We know that the surface area of the parachute should be large enough to increase the air resistance. As we seldom have discussions with each other, the parachute made was not perfect. It was not decorated well. If we do similar projects next time, we may have discussion together first, and consult teachers if there are problems. It is because a good plan is important!

Group list Leader: Chan Kai Yik 4E (21) Member: Chu Ming Kin 4E (23) Lau Ka Wai 4E (28) Li Hok Fung (31) Howard Ng 4E (36)