7, 8, and 9 each need another comma.
The rest are correct,
7) While I was researching skate boards, I found an interesting old newspaper story.
8) In the June 29, 1999 edition of the Mercury, there was an article on skateboarding.
9) Some scientists in San Francisco, California filmed skateboarders in action.
10) As they studied the film, they noticed some rules of science at work.
11) To be a good skater, you have to follow safety rules.
12) Yes, skateboarding is not only a sport, but a science.
13) When you balance on a skateboard, there are three forces at work.
14) The weight of the rider is one force, and gravity is another.
15) Pushing up against the skateboard, the ground also acts a force.
Are these correct?
1 answer