Friday, October 1, 2010

Adapting the convection lab (Investigation 3A: Convection in Earth's Atmosphere

Of all the labs for CPO Earth Science, 3A: Convection in Earth's Atmosphere was the most daunting to contemplate using a homemade system.  The text calls for a "GeoBox" with a special fitted lid that contains two chimneys.  Meet my GeoBox-----an old Rubbermaid box (the size larger than a shoebox), an even older cardboard document box lid that had gone through several moves, and two clear plastic cups left from a party. The other necessary supplies were a tealight candle and a cone of incense, plus a long lighter or fireplace matches and a heat-proof holder for the incense.  We live in a university town with a ready supply of incense LOL:
The ever-resourceful Mike cut out the bottoms of the plastic cups using a Dremel attachment:
Then I inserted the cups into holes cut into the cut-down cardboard lid.  Unfortunately, I inserted them upside down compared to the official GeoBox chimneys, but it still worked just fine.
I attached the lid assembly to the plastic box with packing tape.  The lid wasn't perfectly flat so this helped to create a better seal for the eventual smoke.
As you can see, we needed help from our lab assistant (who was working from home) to keep the lid pushed down.  The smoke wanted to escape out the edges instead of through the left chimney. 
We smartened up and used index card packs to hold down the lid.  I had a hard time photographing the smoke.  If you look carefully at the left chimney, you can see a column of smoke exiting there.  What you cannot see is the smoke re-entering the GeoBox through the right chimney.  The smoke moves from the smoldering incense (cough, cough) toward the candle's warmth, rises as it warms and becomes less dense (exiting), then cools, becomes more dense and sinks back into the box through the right chimney.   The smoke enables one to observe the convection currents in action.
Did you enjoy our geeking-out?


  1. Oh! Wow! Thanks for sharing the documentation of your lab at home. To be honest, doing science at home is daunting to me. I avoid it, but your post is encouraging. I hope you include some more posts like these in the future. I'm off to read your weekly review.

  2. Oh my goodness! This looks incredible. I love how you're able to "geek out" at home. You give me hope that we could do science even when the kids are older! Thanks for posting.

  3. Very cool! Thanks for sharing. I have trouble doing science experiments at home, so it is great to see how someone else does these things. Thanks for some inspiration!

  4. Thanks for the quite reassuring evidence that CPO earth science can be done without the GeoBox and stream table! We have a well-stocked lab around here, at least for chemistry, biology, and physics, but formal earth science is a new field for us, so that cupboard is bare, so to speak. Great posts on adaptations.

  5. wow thats cool ive never seensombody do a science expiriment like that at home

  6. Thanks for the idea! I was wondering what to do.