Since I had a bunch of balloons left over from the previous week’s project, I decided to use them all up this week to encourage the children in the Sharon Elementary Science Club to explore the mechanics of human respiration.
After giving it some mature thought and reflection over the weekend, here is what I presented my future Einsteins with on Tuesday afternoon:
- We started out by briefly discussing the famed fictional detective Sherlock Holmes. Almost all the students knew from the get-go that Holmes was a dazzling detective, but that is about all they knew of him. (I guess Sir Arthur Conan Doyle is not required reading anymore – if it ever was.) So I had to fill them in on the Art of Deduction, and how they, as scientists, would need to sharpen that skill in order to profit from the upcoming experiment.
- As always, I assigned someone to be our secretary, jotting down observations and discoveries as they occurred to the members of the Science Club during our activity.
- I led a short discussion on the gases involved in breathing; we inhale nitrogen, oxygen, and argon – and exhale the same three, although in slightly different proportions, along with carbon dioxide and water vapor.
- Once that was established I passed out a balloon and a jelly bean to each Club member, with instructions to drop the jelly bean into the balloon and blow it up and let the air out several times, and then shake out the jelly bean to see what, if anything, had happened to it.
- There followed a general bedlam for two or so minutes as Club members blew up their balloons the first time and discovered, much to their delight, that a jelly bean inside an inflated latex balloon sounds amazingly like a stampeding herd of cattle when rattled around.
- After they got THAT out of their systems they settled down and performed the experiment with a serious single-mindedness.
- They discovered, among other things, that the jelly bean removed from the balloon was now wet, sticky, cracked, slimy, a lighter color, and no longer smooth but rough.
Now I led them in a discussion as to WHY this had happened to the jelly bean; what was it inside the inflated balloon that had caused the metamorphosis? From the Club members own notes I quote their responses, verbatim:
- Shaking the balloon caused the changes.
- Carbon dioxide was responsible for the changes.
- A few students admitted that they had spit into their balloons, and that undoubtedly had been the cause of the change.
- A few students thought it was the water vapor from their exhalations that had changed the jelly beans.
- One student, by the name of Slade, declared the entire experiment bogus and of nil effect unless we also dropped a jelly bean into a balloon and left it uninflated to see if the same changes would take place. I allowed him to proceed with the challenge, and he had to admit that the jelly bean did not exhibit any of the characteristics of the beans that had been inside the inflated balloons.
And finally, a Club member by the name of Jasmine declared that she was going to try to get a drink of water out of her balloon after blowing it up and letting the air out enough times to distill a pint of water vapor.
I look forward to hearing how her experiment went next week!