Big Idea: Air takes up space.
No matter where you are, or what you are doing, you are surrounded by one of nature’s most mysterious materials. It takes up space, but you can’t see it. You can’t hold it in your hand, but it fills up all empty spaces. And most importantly, you can’t live for more than five minutes without it. What is this fascinating substance? Air!
Exploring air with kids is a magical experience. Adults accept that air exists, but children must be convinced that this invisible substance is real. They need to see and to feel something in order to understand how it works. They need to see that air takes up space. They need to feel air exert force on objects they can see. And finally, they need to understand that it can’t simply vanish without a trace. So how do we show kids that air is always here, there, and well, everywhere?
First, you have to find fun tools for capturing it: bottles, balloons, bubbles, and straws are all excellent air traps. This week in the Wonder Ground, we got a little fancier. We used syringes, turkey basters, and water.
Next we set aside the water in order to examine the syringes. We took them apart, identified the parts, and discussed how they work.
We put them back together and practiced moving the the plunger up and down to learn how to operate them properly without any water in them. The kids observed that when they pushed the plunger in with the tip pointed at their cheeks, they could feel a little puff of air sweep across their faces.
Then I passed out cups of water, and we got down to business. We pushed the plungers all the way in, and dipped the syringe tips into the water. Then we pulled on the plunger until the barrel was filled about halfway. We examined the barrel looking for bubbles. At first, some kids were confused. They were looking for something that looked like a soap bubble. But one wondergrounder offered up a great definition of a bubble. He said, “a bubble is a pocket of air enclosed in liquid.” This helped the other kids identify bubbles in their syringes.
Finally, we placed our fingers over the tip of the syringe so no air or water could escape, and pushed on the plungers. The plunger wouldn’t budge. We pulled on the plunger. The plunger didn’t budge. We took our fingers off the tip, and pushed gently on the plunger, and water shot out all over the table. This sent everyone into a fit of giggles. We refilled the barrels and sealed the tips with our fingers again. This time when we pushed and pulled the plungers, we watched the bubbles closely. On close inspection, we could see the bubbles expand when we pulled on the plunger, and shrink when we pushed on it. This demonstrated the day’s Big Idea perfectly: air takes up space. It also helped us define two new words:
Expand: To become larger or to take up a larger space.
Compress: to press on something until it takes up less space.