Hi, that's a good question! A joke usually is something you say. You can tell a joke. A prank is something that you do to some. We would play a prank. It usually would be giving someone they didn't expect, like putting something gross in their food, or making a tool they use work differently. Pranks are more complicated than jokes. I think, usually if you tell some a joke, they will laugh with you. If you play someone a prank though, you will laugh at them.

Oh- well, pranks can be harsh, or not too harsh. Some pranks might be very mean, like vandalizing someone's things, or they might be silly like filling up a bathroom with balloons, or putting garlic powder in the tip of a toothpaste tube. It tastes gross for a minute, but it doesn't ruin anything. Some pranks are friendly, but almost all are irritating to the victim.