Science Project Details:

Wind resistance and automobile shapes

Featured science projectScience project video Intermediate 6 < 3 days $25-$50 Readily available [+] More info
Difficulty: Intermediate 6
Cost ($): 40
Time required: < 3 days
1 day to preparation, 1 day for observation
Availability of materials: Readily available
Easily found. An industrial strength fan may be purchased at Lowes/Home Depot or other hardware stores
Required Skills: None
Safety concerns:

Basic safety requirements
 

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Abstract

This science fair project aims to ascertain how the shape of a car affects the amount of wind resistance that arises when the car is in motion. The experiment is carried out using polyfoam cut outs of various shapes - rectangular, low profile rectangular and low profile streamlined in order to compare how much wind resistance each shape experiences.

Hypothesis

Cars that are have low profile, streamlined shapes will experience  a lower amount of wind resistance
 

Scientific Terms

Wind resistance, drag, fluid dynamics, streamline

Background

Wind resistance

Wind resistance is a  force opposing the movement of an object through the air. It is also known  as drag force in fluid dynamics (namely, the forces which oppose the relative motion of the object through the fluid (be it a gas or liquid). The amount of wind resistance faced by the moving object will increase as the object moves more quickly through air.

The shape of the moving object will also determine the amount of wind resistance it experiences. A body with a flat surface, such as a cube, will experience greater wind resistance compared to a body with a pointed or streamlined shape. This is taken into consideration in  the design of aircraft and automobile structures  in order to reduce fuel consumption and increase speed.

When the speed of the moving vehicle increases, the wind resistance  increase as well. When  Interestingly, when a vehicle moves at speeds greater than  100km/hour, about 30% of the fuel consumed to propel the vehicle is used to overcome  wind resistance. Hence, wind resistance is a very important factor that vehicle manufacturers take into account, when designing a vehicle.