Is it actually bad to crack your knuckles?
You may have noticed that when your knuckles are pushed a little further than they normally go, they make a "popping" sound. Sometimes this is a little painful, while other times it may feel like a slight relief. This is what is referred to as "cracking your knuckles."
The reason knuckles (and other joints such as necks, ankles, and toes) make this popping sound is that they're filled with a special liquid called "synovial fluid," which helps your joints move and bend easily. When a joint such as your knuckle is pushed past its normal position, little bubbles in this fluid are popped, leaving you with that cracking sound!
Many people say cracking knuckles or other joints is bad for you, and causes problems when you're older such as arthritis, which is when your joints are painful and sore. Most doctors seem to say that this hasn't been proven to be true, and that the most common risk for knuckle-crackers is mild temporary pain. However, most doctors also seem to agree that it's better to play it safe than sorry, and to leave all the popping up to popcorn!
Exploration
Jointly cool!
How many joints do you think that you have in your body? Try to count as many as you can a few in each finger, both elbows, shoulders, knees, ankles, neck, and quite a few in your toes and feet, too! Your list might already be higher than you can count, but that's just because there are so very many joints in the body!
The total number in the whole body is 230!!
Why do you think it's helpful or important to have so many joints? What do you think it would be like if you have fewer? What about if you had more??