What is a bike helmet and how does it work?
A helmet protects your brain when you fall. It has a plastic shell on the outside and foam inside. It has a strap to keep it on when you fly through the air. It only covers your head, and the rest of your body is still exposed. So you still have to be careful. It is better not to crash at all, then to crash wearing a helmet. But if you do crash, a helmet works to absorb the force, which protects your head, which in turn protects your brain. Helmets work to prevent head injuries which becomes even more important for children whose brains are still developing.
How does a helmet work?
The foam crushes when you hit the road. That cushions the blow, and usually saves your brain. The shell makes it skid on the street so your neck does not get jerked. The shell also keeps the foam in one piece. If the strap is not right, your helmet can slip to the side or to the back.
Find a helmet that fits you. That's really the most important part. That will keep it on your head while you fly through the air or over the handlebars. Work on the straps to get the fit just right. You will probably need somebody to help you do that.
You don't have to pay a lot for a good helmet. But be sure it fits you, you like it and you will wear it. Your helmet is good for only one bad crash. That damages the foam and you have to replace it.