Recently (on a much cooler day), I discovered something while driving to volleyball practice at night. It was chilly so I had the heat on in my car, but just on low. Upon turning on the highway, I suddenly noticed that the heat seemed to have been turned up! That wasn't right, how could it do that on its own?! I double checked it, but the switch hadn't moved; the heat was still on the lowest setting.
So why did it feel like hot air was blowing twice as fast into my face? Well, when I thought about it, the answer was simple: inertia. As the car accelerates forward (as it does when entering a highway), the objects - including hot air - inside the car want to stay put. This is the same reason why you feel thrust forward when you slam on the breaks, or slammed against the wall when you make a sharp turn. Your body wants to keep moving in a straight line due to inertia (as Newton says, "an object in motion tends to stay in motion").
So, what does this have to do with the hot air in my car? Well, it too has inertia and wants to stay at rest unless acted upon by an outside force, so when I accelerated onto the highway, the hot air stayed in place. Since the car itself was accelerating forward while the air stayed put, it made it feel like the hot air setting had been turned up as it blasted in my face. In reality, it was me (and the car) accelerating into the hot air.
Anyway, I thought this was pretty cool. Hopefully you thought so too! Thanks for reading.
Until next time,