An Investigation into how the Area of a Parachute Affects the Speed that the Parachute falls from a set height.

Introduction

In this investigation I will test five different sized parachutes to find out weather the bigger the parachute is the slower it falls. I am going to try and keep the test as fair as possible but there are a lot of things that can affect the experiment so the results might not be entirely accurate.

Diagram

Method

Firstly I decided what size range of the parachute I was going to use I decided that the range would be 15cm diameter to 35 cm diameter going up in 5cm intervals because the material I was going to use was to small to get use any bigger sizes than that. Below is a table of information about the range I have chosen.

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I then set up the experiment and got ready to carry it out. I needed two people for this experiment to be recorded fairly, myself and one other person to operate the stop clock. I then stood on top of a desk and then reached as high as I could comfortably and safely reach we then measured this height and made sure all subsequent drops were dropped from the same height (2.5 Meters). I held the top of the parachute with pinched fingers and had the set weight on the bottom (this weight will remain the same through all tests) I then let go and timed how long it took to reach the floor. We did this 3 times for each size of parachute so that we can get an average result.

Fair Test

To make sure this experiment is fair and done with the most accuracy then there are several things that need to be done to ensure it remains a fair test for the whole experiment.

Using the same type of material for the parachute for all tests.
Using the same type and length of string for each test.
Using the same weight of plastercine in the bottom for all tests.
Dropping the parachute from the same height for all tests.
Trying to keep the same or similar weather conditions for all tests.
Using the same ...

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Fair Test

To make sure this experiment is fair and done with the most accuracy then there are several things that need to be done to ensure it remains a fair test for the whole experiment.

Using the same type of material for the parachute for all tests.
Using the same type and length of string for each test.
Using the same weight of plastercine in the bottom for all tests.
Dropping the parachute from the same height for all tests.
Trying to keep the same or similar weather conditions for all tests.
Using the same stop clock for recording the drop time for all tests.

I will try to apply all of these fair test conditions when performing the experiment this was we will receive the best and most accurate set of results.

Prediction

From my research into parachutes I have discovered that through history parachutes have been used for getting people safely to the ground from high places. I have also discovered that air resistance plays a large part in the drop speed of the parachute. This has made me come to the prediction that my experiment will also be affected by air resistance and the larger the surface area of the parachute the more air resistance there will be. My prediction is as follows:

The larger the surface area of the parachute the longer it will take to complete the drop.

Results

Below are my results as you can see I have worked out the average drop time and shown the height I dropped it from each time.

As you can see from the table I only did 5 different parachute sizes because the material that we used for the parachute was a plastic carrier bag and the biggest you could make the circle was 35cm so I decided to go down in 5cm intervals.

I have now analysied my results and created a graph with them. I used the Average Drop Time in it and discovered that the larger the parachute’s surface area (diameter) the longer it takes to fall. I discovered this as the graph below shows a possative correlation, this displays that as the diameter of the parachute increased the time taken for drop increases.

Analysis/Evaluation

From this experiment I have discovered that:

The larger the area of parachute the longer it takes to fall.

My Graph proves my Prediction with the positive correlation and the results being close to the line of best fit. Although my experiment did have a few problems an anomalous result was taken with diameter 25cms as that is quite far away from the line of best fit.

Also it is very difficult to get accurate results for this experiment because when recording the times another factor affects it, this is the ‘Human Reaction Time’ this is the amount of time it takes for so one to press the start and stop buttons on the stop clock making the test not entirely accurate. Also with us being in a classroom environmental conditions didn’t affect the experiment as much as they would of if we had done the tests outside but there is still an element of disturbance with drafts from under the classroom door etc…

If I had done the experiment again I would of tried to find a more accurate form of taking the results e.g. infra red (motion sensors), This would of cut out the human reaction time and increased the reliability of my results.

The results I did get were reasonably accurate and did follow the correct pattern so my prediction and information I concluded from my results was correct but could have been better.

The fact that the larger the surface area of the parachute the longer the drop time is useful to know and understand because:

When people are jumping from airplanes or ejecting from fighter planes then the designers need to know how big the parachute should be. Also in theory someone could have a extremely large parachute and spend a lot longer in the air. The only problem with this I have discovered from research is that if you get caught over a current of hot air you could end up rising higher because the hot air turns the parachute into a hot air balloon and you could end up getting stuck up in the sky for some time because it is possible for you to get stuck in these hot air currents for some time. This most recently happened in the 2nd World war when Para gliders jumping from airplanes got stuck above the battlefield because of all the fire and hot air being given off.

Since then the parachute has been re-designed so that this cannot happen anymore because the parachute isn’t big enough.

Michael McLean 11LH