As winter temperatures plummet, low tire pressure warnings will start illuminating dashboards.
This common occurrence is not just a distraction; it can negatively impact tire performance and gas mileage.
But how does the winter chill seem to take the air out of your tires?
The phenomenon can be understood through the Ideal Gas Law, which you may have seen before in chemistry class; PV=nrT.
To see the relationship better, we’re only looking at one kind of gas so we can drop n and r. Then, we can simplify this further by sealing off the container and holding the volume to a fixed value.
From here, we only care about the relationship before and after a temperature change. We now see that if the temperature rises, the pressure will rise, and vice versa.
This is because molecules in a gas are constantly moving, and will move even faster when more energy or heat is added.
When these molecules move faster it takes longer for the molecular bond to slow them down and move back together, which allows the gas to take up more space. Because our space is fixed, the pressure in the container will rise.
If we cool it down, the molecules within the gas will slow down, taking up less space, and allowing the pressure to drop.
We can see how this works rather through a simple experiment you can even try at home! You just need an empty water bottle, a balloon, a bowl of hot and a bowl of cold water.
When the bottle is placed in the hot water, the temperature inside the bottle rises, creating more pressure and inflating the balloon on top.
Dipping the bottle into ice-cold water drops the temperature and the pressure, deflating the balloon.
Going back to our tires, the general rule of thumb is for every 10 degrees drop, the pressure in tires will change about 1-2 psi.
Lower psi can make it harder to handle your vehicle in the wintertime. So, when you see that low tire pressure light flick on, be sure to inflate your tires for a safer ride this winter.
This post was originally published on here
