Mach number

Hey kiddo, do you know about airplanes? Yes? Great! So, when airplanes go really fast, we have a special number to tell us just how fast they're going. That special number is called "Mach number".

Now, Mach number is like counting how many times you can jump on a trampoline really fast without stopping for a breath. But instead of counting the times you jump, we're counting how many times faster you're going than the speed of sound.

You see, sound travels at a certain speed in the air, and it's really fast! But when an airplane goes faster than that speed, we call it "supersonic". And we use Mach number to compare how fast the airplane is going to the speed of sound.

So, if an airplane is going twice as fast as the speed of sound, we call that Mach 2. And if it's going three times as fast, we call it Mach 3, and so on.

That's basically what Mach number means. It's a special number that tells us how fast something is going compared to the speed of sound. And it's really important for pilots because it helps them know how their airplane is flying and what they need to do to stay safe.