Explaining the concept of air pressure to preschoolers can be tricky. It can sometimes be difficult for them to grasp the idea that spaces are filled with air, and that air can have force and move objects.
This simple little experiment a great way to offer kids a visual demonstration of these concepts. They can feel the air on their skin and see it moving objects. It is also a lot of fun!
This is so simple to set up. Simply place the two kitchen sponges, one on top of the other, inside the plastic zip lock bag. Place the drinking straw between the two sponges so that one end of the straw is inside the bag and the other end is sitting outside the bag. Seal up the bag. In addition to closing the zip lock seal on the bag, you will also need to seal it with adhesive tape. The tape is not showing in the photo above. We first tested it out by just closing the zip seal but the bag burst open during the experiment. So, seal up your bag with adhesive tape and then you are ready to play!
Place a pom pom on a flat surface and place the bag behind them so that the straw is positioned to blow the pom pom. Press down hard on the sponges and watch the pom pom roll away! My son decided he wanted the pom pom to be moved with much greater momentum so he blew air into the straw, filling up the bag as much as he could. He then gave it another try and the pom pom really flew off the table this time around.
Try holding the bag at different angles. How does this affect the pom pom? It would be fun to turn this into a game of air-soccer. Simply lay a container (eg a tin can, a paper cup or an empty tin can) on its side and try to shoot the pom pom into the goal.
We also tried to move other objects such as toy cars and Lego mini figures. Some of them moved and others didn’t. Try to make predictions about what you think will be moved and then test your theories. Can you think why some objects are moved by the air and others aren’t?