Our investigations last Friday left us feeling pretty good about gathering evidence if air, water, and light had weight. We still didn't have total agreement on air having weight, so we did our air investigations again as a class (this time with a balloon-pump and a basketball pump to alleviate any spit). We gathered evidence in a fair test that both the air in the balloon and the air in the basketball had weight, so we agreed that air definitely has weight, although not much. We revisited our light experiments, too. And to no avail, no matter how much or which type of light (natural or artificial) we put on the scale, the scale always registered 0.0g.
This got us thinking about what light could look like at a zoom-in level, since we proved it has weight. Some students shared their thinking and created models like this:
This got us thinking about what light could look like at a zoom-in level, since we proved it has weight. Some students shared their thinking and created models like this:
We began thinking about a few things. If air does have weight, can it be just "nothing?" Also, if we can take air in a syringe and compress it, mustn't that mean it takes up space, too? And in order for it to be compressible, doesn't that mean there has to be empty space around the particles to move closer together? After a thoughtful discussion, we agreed that like water, air must be made of particles w/empty space around them, too! |
We updated our model trackers to reveal this new stuff we figured out about water and air having weight, light not having weight, and air being made of particles! So now we're thinking... If plants need air and water to gain weight and grow, and light doesn't have weight, what does light give plants if it needs it? |