1. To determine that the surface area of a parachute can affect the time it takes to travel a calculated distance, and therefore affecting the speed at which it falls.

Hypothesis:

1. The surface area of a parachute affects the time it takes to travel a calculated distance, and the speed at which it falls.

2. Parachutes with a larger surface area will fall slower than ones with a smaller surface area, and will also take a longer time.

Background:

Parachutes are used by people in order to land safely from the air. These parachutes work on the basic law of air resistance. As a parachute opens up, it causes resistance against the air, causing the person using it to slow down. There are several factors that affect the way a parachute falls. These include; weight of user, force of winds blowing against the parachute, direction of winds against the parachute, material of parachute, weather conditions and surface area of parachute. In this experiment we will explore the factor of surface area of the parachute, which affects the way a parachute falls.

Variables:

Constant Variable – Distance traveled by parachutes & weigh of the plasticine.

Independent Variable – Surface area of parachute.

Dependent Variable – Time taken by parachute to fall & speed of the parachute.

Materials:

1. Polythene sheets – minimum size = 25cm x 25cm – 5 sheets.

2. Thin string – Length = 1400cm.

3. Meter Rule.

4. Plasticine – 5 grams.

5. Sellotape.

6. Scissors.

7. Electronical Stop watch (? 0.01 seconds).

8. Weight Balance (? 0.01 grams).

9. Area with a flight of stairs.

Method:

1) Take a plastic sheet of paper and using a pair of scissors and a meter rule, cut out a 5cm by 5cm square, which is 25 cm2.

2) Now using a pair of scissors and a meter rule, cut out 4 parts of the thread, each the length of one side of the polythene parachute or of a larger length.

3) Now using tape, connect each string to a respective corner of the polythene parachute.

4) Now take a mould of plasticine of weight 5 grams and attach it to the ends of the 4 strings.

5) On the flight of stairs, measure the height of the stairs from where you want the parachute to land, to where the person dropping the parachute is going to be standing.

6) Measure the height of the person dropping the parachute. And add this height to the height measured in Step 5.

7) Hold the parachute from the center of the polythene sheet and keep it at the level of your height.

8) While holding a electronical stop watch in your hand, drop the parachute onto the place where you want your parachute to land, simultaneously starting the electronical stop watch.

9) As the parachute hits the area you wanteded it to land, stop the electronical stop watch.

10) Note down the time taken. Take minimum of 3 readings.

11) Repeat the experiment for the following dimensions: 10cm by 10cm (100 cm2), 15cm by 15cm (225 cm2), 20cm by 20cm (400 cm2) and 25cm by 25cm (625 cm2).

Data:

Weight of Plasticine used = 4.98 grams.

Distance traveled by parachute = 3.30 meters.

Data Table – 1

Attempt No.

5cm by 5cm

(25 cm2) (? 0.01 seconds)

10cm by 10cm

(100 cm2)

(? 0.01 seconds)

15 cm by 15cm

(225 cm2)

(? 0.01 seconds)

20cm by 20cm

(400 cm2)

(? 0.01 seconds)

25cm by 25cm (625 cm2) (? 0.01 seconds)

Attempt 1

0.65

0.70

1.50

1.63

2.72

Attempt 2

0.62

1.00

1.13

1.72

2.32

Attempt 3

0.63

0.87

1.37

1.69

2.35

Average Time

(? 0.01 seconds)

0.64

0.86

1.33

1.68

2.46

Average Speed

(? 0.01 meters per second)

5.16

3.84

2.48

1.96

1.34

Graph 1

Interpretation: As you increase the surface area of the parachute, the time taken increases and the speed decreases.

Observations:

As we increased the surface area, the parachute took longer to land, therefore resulting in it to land more slowly.

Analysis:

As you increase the surface area, the amount of air resistance caused increases. This is because there is more polythene against the air causing more resistance. This results in the parachute taking a longer time to land, which then affects the speed of the parachute, which becomes slower as we increase the surface area.

Conclusion:

1. Our first hypothesis stated, “The surface area of a parachute affects the time it takes to travel a calculated distance, and the speed at which it falls.” We were able to prove this hypothesis right via the data we collected and our observations during the experiment. Therefore we can conclude that the time taken and the speed of a parachute is affected by its surface area.

2. Our second hypothesis stated, “Parachutes with a larger surface area will fall slower than ones with a smaller surface area, and will also take a longer time.” We were able to prove this hypothesis right via the data we collected. Therefore we can conclude that parachutes with a larger surface area fall more slowly and take a longer time than ones with a smaller surface area.

Therefore, if a person using a parachute would want a soft and safe landing with ease, they would use a parachute with a larger surface area.

Errors and Modifications:

1. The square cut out of polythene were not exactly a square.

2. While the parachute was traveling, there could have been air blowing from any of the directions, causing a change in the time taken by the parachute, and therefore its speed.

3. As the steps are not level, the parachute may not have landed one or two steps lower, making it travel a longer distance, causing a change in the time taken by the parachute, and therefore its speed.

4. If the parachute was folded a little more than another, it would take longer to open up, causing a change in the time taken by the parachute, and therefore its speed.