# Charles Law!

## Charles Law with NASCAR!

Nascar tires are inflated with nitrogen rather than normal air because of nitrogen's ability to remain stable under the temperature differences the NASCAR tires endure.

NASCAR tires can reach up to 200 degrees Fahrenheit.

Nascar tires are inflated to a pressure of 50 psi. (pounds per square inch)

Why NASCAR drivers should be aware of Charles Law:

Lets say a NASCAR tire was inflated to 50 pounds per square inch with normal air on a 75 degree Fahrenheit day.

Once the car begins racing, the tire can reach 200 degrees Fahrenheit!

75° F = 297.039 K

200° F = 366.483 K

(50) / (297.039) = (x)/(366.483)

x = 61.7 psi

Using the Charles Law equation shown above, once the tire heats up to 200 degrees, the pressure increased 11.7 psi! This could affect the driver's handle on the car and may even damage the tires!

Luckily NASCAR uses nitrogen which is more stable than normal air so NASCAR does not need to worry about this issue any longer, although it wouldn't hurt to know.