Even when the air doesn’t move fast or hard enough to notice, you still see evidence that it moves. When flags lie limp against the flagpole, direct the preschoolers to look high in the sky and notice clouds slowly moving or leaves moving at the top of trees. With a stronger breeze, ask preschoolers to look around and find evidence of air movement such as flags waving or debris in the air. Ask the children if they feel the wind on their faces and in their hair. During a heavy rain or snow, watch the wind push the precipitation so it falls at an angle or drifts in eddies to the ground.
Humans and animals harness the air to move. Birds, flying squirrels and insects use the air to fly from place to place by gliding on the currents or flapping their wings. Humans drift on air currents in hot air balloons or gliders and move on the water with wind in sails. Help preschoolers launch a kite, a paper airplane or a helium-filled balloon to watch how air lifts and pushes an object forward on air currents. Demonstrate how moving with the air works more effectively than moving against it.
Show preschoolers how air under pressure tries to escape. Blow a balloon full of air, but don’t tie the balloon closed. Have the children watch as you release the balloon and the compressed air rushes out of the balloon, sending it whizzing around the room until most of the air escapes. Twist the opening closed and demonstrate that the balloon still holds some air because the balloon won’t completely flatten. Refill the balloon and tie it closed. Try to submerge the balloon in a bucket of water. Explain that the air in the balloon pushes against the water, keeping the balloon from deflating as it did when you released it with the opening unsecured. Point out that the air weighs less than the water, so the balloon rises to float on the water.
Most living creatures need air to live. Have the preschoolers lie on the floor and place their hands on their abdomens. Tell them to feel the pressure of the air as it lifts the diaphragm under their fingers. Next, have them feel the pressure release as the air rushes out when they exhale. Compress the bulb of a turkey baster and demonstrate how a vacuum pulls air in when you release the bulb. This negative pressure helps the lungs expand for each breath.