Est-ce que la forme d'un parachute effet sa vitesse a descendre?
Winnie Kan
Vancouver Technical Secondary
Floor Location : J 001 D

I try to find out: does the shape of a parachute, even with the same area effect its descending speed? I used 5 different shapes: a circle, a hexagon, a triangle, a rectangle and a square. Before I started the actual experiment ,I made a hypothesis: I thought that the circle would drop the slowest because it's surface is more equal and balanced.

I started by finding an area of 90 cm2 for all the shapes. Unfortunately, i could not find the area of exactly 90 cm2 for the circle and the square, but it was only a little bit off. ( Ex: 90.25 cm2). To make mini parachutes, i measured and cut out the 5 shapes and attached 4 strings that were 30cm each to each shape with tape. I then tied the 4 ends of the strings of each shapes to a paper clip. Then, i added a binder clip as a weight to the paperclip. Next I Dropped each of them , from 200cm of height, 10 times each and timed it with a stopwatch. After that, I calculated the average descent time for each shape, by adding all the times for each shape ( invididually ) and then i divided it by 10 ( because I dropped each parachute 10 times ).-- These times are not assured to be exactly accurate because the person who dropped it and also the person who timed it has reactions so its not completely accurate but it was the best I could do--

By looking at the average times, the circle dropped the slowest and the rectangle dropped the fastest. The hexagon surprisingly worked really well also and I think it is because a hexagon is basically a circle only with edges and corners.

I did some research to see why the circle worked the best. - I found out that it is because the surface of a circle is more balanced out and it traps a lot more air when its descending than other shapes. On the other hand, a shape like the rectangle also traps air, but a lot less and it drops faster because it lets the air exit through the edges instead of trapping it.

So in conclusion , my hypothesis was right and yes, the shape of a parachute, even if the shapes have the same surface area will effect it's descending speed.