Science Project Details:

How does the air pressure in a football helmet affect cushioning?

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Difficulty: Intermediate 5
Cost ($): 30
Time required: < 1 day
5 hours preparation time, observation time only takes a matter of seconds. However, do allocate some extra time in case of any mistakes.
Availability of materials:
Besides the helmets, all the other materials should be obtained from a school laboratory.
Required Skills: None
Safety concerns:

Be careful to keep clear of the falling weight.

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Abstract

The purpose of this experiment is to find out the use of air pressure in the padding of the helmet and how different amounts of air pressure would affect its wearer. American football is a very physical sport which involves body to body contact and human to human collision. In order to protect the player’s body from being injured, various safety features are implied onto the player’s attire. The air pressure in the padding of a helmet is a good example of such safety features.

Hypothesis

The higher the air pressure in the padding of the helmet, the smaller the force of impact.
 

Scientific Terms

force of impact, accelerometer, air pressure

Background

Air pressure

Air pressure is the output force exerted on a column of air in a specific location. Air pressure in a container can be modified in 2 ways. The first way is by increasing the amount of air which increases the density of air in the container. The other way is by increasing the temperature which results in air molecules having more kinetic energy which in turn make them move faster and collide with increased frequency.
How is air pressure measured?

A barometer is used to measure air pressure. There are two most commonly used barometers, which are the mercury barometer and aneroid barometer.
 The mercury barometer’s major feature is the glass tube filled with mercury. The tip of the tube is a vacuum. When air pressure increases, the mercury level increases and vice versa in low air pressure.

The aneroid barometer has a slightly different structure; it uses an aneroid or sylphon cell to measure air pressure. The aneroid cell is basically a metal chamber that contracts and expands under different air pressures.

Force of Impact

An impact occurs when 2 or more bodies collide, causing an intense shock for a short period of time. The intensity of this impact depends on the amount of force applied, the length of impact time and the speeds of the colliding objects.

With high speeds and a high amount of force, there would be deformation of the object being struck at the point of impact.  Much like punching a sponge, the object being struck (the sponge) would deform when you punch it. However, if the object being struck was more brittle in nature, it would fracture. When 2 speeding vehicles crash into each other, metal is bent and twisted, as a result of the force of impact.