Ball up a piece of paper, cotton ball, balloon, small ball, or feather.
Each child should try moving the ball from one place to another by blowing the ball.
You can have them blow directly or try using a straw to increase the pressure of the air to see if the ball moves further/faster.
Do the objects move quicker when you add more children/wind power? Which object was easiest to move? Which was hardest? Try graphing your results.
For more activities to bolster movement this winter check out our March blog post, Spring Fever: Indoor and Outdoor Activities.