Millimetre of mercury

Okay kiddo, imagine you have a straw and a glass of water. When you suck on the straw, you create a vacuum that pulls the water up the straw. Now, instead of water, imagine we are talking about air. When you suck on the straw, you create a force that pulls air molecules up the straw.

Now, imagine we had a super strong straw that could lift a column of air up to a certain height. We could measure how high the column of air goes up by using something called a millimetre of mercury. Mercury is a type of liquid metal that's used to measure pressure.

When we talk about millimetre of mercury (mmHg), we are measuring how high the air column could go up the straw if we were using mercury instead of air. It's a way to measure how much pressure there is in the air.

For example, if we measure the pressure in a tire using mmHg, we can see how much force the air is pushing against the walls of the tire. Higher mmHg means higher pressure, and lower mmHg means lower pressure.

So, think of a millimetre of mercury as a way to measure how much pressure is in the air. It's like a ruler for air pressure!