The next time you are at the ballpark, observe how the wave moves through the stadium. You can try this with your hand. Lift one finger up at a time and put it down before you lift the next finger. Notice how the motion is like the wave.
Questions to ask:
Are people waving their arms or just lifting them up and down? (The up and down motion makes the wave).
What happens if you stand up before the wave gets to you? (It won’t look like a wave).
What has to happen for the stadium wave to be successful? (Repeated motion of people standing up and sitting down has to happen).