Summer vacation homework

I made a physics machine in my vacation. I used Lego, bounce ball, needle, and fishing line in physics machine. First time, I used styrofoam to balls. But styrofoam balls were too light to use. And they move what they want only. So I used bounce balls which it has a weight. I put needle in bounce ball and used fishing line to not to get out and used nail too. And I made a hole because, lego have to go in. It was a little bit hard so father helped me to make. I have 2 fails in making. But the result was good. I thanked to my father.

 First, I put needle in bounce ball.And in needle it has a hole. So I put fishing line through there. And in the fishing line, I put two fishing line together and tape it. And I made a hole like in the second picture And put screw in to the hole and I made basic step for 1hour. I used baby lego to build.

I took 3 days because I failed 2 times in here. I was made in stryofoam for the balls. And it is too light so I failed. And I put clay in there, but it failed one more time. So I spend 3days to made this.