Why do you need pencils for grades 1 to 3 in elementary school, pens for grades 3 to 6, and water pens in middle school? Aren't they all pens?

Children should use pencils for grades 1 to 3 in elementary school because they have a bad writing posture, and the pencil always falls toward the outside (in the opposite direction from the body). Children in grades 1 to 3 are also prone to misspellings and easy to scribble, leading to loss of marks on the paper. Therefore, first through third graders write in pencil. And fourth through sixth graders are the ones who begin to learn to write with a pen that cannot be scribbled on for the future. grades 3 through 6 use pens because writing is only a little bit advanced, so they have to learn to write in pen. Moreover, fountain pens are able to write like pencils, and you can see the force. That's why fountain pens are usually used in grades 3 to 6 in elementary school! In middle school, there is more homework, and there is no longer a need to write properly, otherwise it would be a waste of time. That's why they start to use water pens. Also, when you grow up and work, you are usually given a water pen, so you need to get used to writing with a water pen in middle school.

(This answer is purely my own answer, without any reference answer, I hope to be adopted)