The Area of a Parachute Compared To Its Rate of Descent

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The Area of a Parachute Compared To Its Rate of Descent

Introduction

This experiment is designed to measure the time that it takes in order for different sized parachutes to fall a certain distance.  This is done in a specific way that makes this very fair and accurate.

My prediction is that, the larger the area of the parachute, the lower the rate of descent, this is because if the parachute is larger, it will trap more air underneath it, and will take longer to fall.  The smaller the parachute, the less air it will trap underneath it, and it will take less time to fall.

Background Information

Parachutes fall according to their air resistance, this can be calculated by their area, such as an average human body falls at 9.81 m/s, a parachute can have this calculated, which is one of the purposes of this experiment.  The area can be calculated by A=πr², where A is the area, π is pi and r is the radius.  The speed can then be calculated by the time it took to fall to the distance calculated, Distance (m) = Speed (m/s) × Time (s), rearranged to get:

Speed = Distance ÷ Time.  The speed that is calculated is the rate of descent.

Parachutes fall by trapping air underneath them and increasing the air resistance.  This makes the air resistance larger or equal to gravity so that the parachute now falls at a slow rate.  The slow rate of descent is slow enough to stop objects that are very aerodynamic, as long as the object is not too heavy for the size of parachute, such as weights or human bodies.

The structure of a parachute means that it has to displace air in order to float, otherwise, the edges would flap around and there would be little reduction in air resistance.  This is achieved by making a small hole in the centre of the parachute, which lets the air escape.

Apparatus

Safety

Key Factors

There are many variables in this experiment.  The two main types of variable are controlled and manipulated.  The manipulated variable is the only varying variable in the experiment.  This is used to measure what happens when a something is altered in an experiment.  The manipulated variable in this experiment is the area of the parachute and the length of the strings that is being used.  This factor is controlled so that it rises at a constant rate, and it keeps the experiment fair.

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There are also controlled variables.  These variables are ones which do not want to be changed, in order to keep the experiment fair.  The variables have to be controlled so that they do not make this an unfair test, hence the name controlled variables.  These variables are such things as the height from which the parachutes are dropped, the weight attached to the parachute and the type of plastic used to make the parachute.  These can be controlled by keeping them the same for every experiment, but variables such as the hole in the top of the parachute have ...

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