PARACHUTES

Today my group and I did a lab that consisted of making a parachute, strong enough to hold up a "person" (binder clip & metal stick figure) when blown upwards by a hairdryer, but light enough to float down so our "person" wouldn't get hurt. Our first attempt was a piece of plastic bag about 0.5 meters by 0.5 meters. The ends were hole-punched with reinforcements and pieces of string in them that held our "person". We held the hairdryer right under the bag and turned it on to high. but the parachute floated all over and sank heavily to the ground.

In the second trial we cut a hole about the size of billiard ball in the middle of the plastic bag. We thought this would work better because then all the air from the hairdryer wouldn't be concentrated under the bag without an outlet for the extra. When we held the hairdryer under the bag, the whole parachute flew away and sank again. Then we used the same design but this time, we put the hair dryer under the "person" on the bottom of the parachute, instead of right under the bag. This worked well- we were able to hold the parachute up stable for about 20 seconds. I think the reasons why the hairdryer under the parachute works better is because:

1. You can't get the hairdryer exactly in the middle of right under the bag, so this tends to blow it all over (and since we had no extension cord for the hairdryer, it was hard to keep up).

2. Also, even on the lowest hairdryer setting, there is a lot of air blowing upward so it caused the bag to crumple a little.

3. Lastly, when the air was under the whole contraption, it forced our "person" as well as the parachute to be held up, not just the bag.

4. In real life, air pushing upwards will becoming from under the person, not just under the bag.

Relation to Newton's 3rd law:

Newton's 3rd law states that for every action, there is an equal and opposite reaction. This law plays a part in this experiment, because in the world with no other forces, except the ones in Newton's 3rd law, the parachute would float in the air because as the air pushes up on the bag, an equal force pushes down so it would stay in one place. The reason parachutes float down to earth is because even though the actions are the same, gravity is pulling down the parachute towards earth (at 9.8 m/s^2) and earth is the closest most massive object with a strong gravitational pull.