In what grade do children have the fastest reactions? We predicted that children in grades 7 and 8 will have the fastest reaction, because children at this age tend to be in more physical activities and are more hyper active. Our hypothesis was wrong; the results showed that grades 11 and 12 people have the fastest reactions. Two major factors that affected our experiment was the time of day it was and who was watching the experiment. If we were able to change how we did our experiment we would have done our testing all at the same time of the day. We also, would have left the room as the students danced. We would then go in after each song was finished.