If Junior is looking for a spectacular science fair project, they can’t go wrong with this project from 80 years ago, from the November 1942 issue of Popular Science.
Octopus furnace. Wikipedia image.
It demonstrates how an old-fashioned “gravity” furnace works. These are often affectionately known as an octopus furnace, since they had tentacles going from the furnace to each room. As shown clearly by this experiment, the air in the furnace heats up and rises. Then, when it gets to the room, it cools and returns through the lower set of pipes.
Such furnaces are out of favor, and I doubt if they are still manufactured. But there’s really nothing that can go wrong, so they still exist in some older houses. They are not as efficient as modern furnaces, but they have some advantages. Unless some electronic controls have been retrofitted, they don’t require any electricity to operate. In the event of a winter power outage (see our earlier post for more thoughts), modern furnaces would be useless, even if they burn gas or oil, since they need electric power to run the blower. But the old gravity furnace will keep the house toasty warm, even with no electricity. Back in the day, the homeowner would shovel coal to keep it going, although most were converted to gas or oil.
To put the experiment together, in addition to the items found around the house, Junior might need to purchase the following items. You can find them locally, but as with everything, you can also find them on Amazon, at the links below:
- Saran Wrap
- Mailing tubes (or just use paper towel tubes).
- Candle
- “Joss stick” incense
- Sealing wax
- Other fancy stuff
As with many of our science fair projects, don’t forget to give Junior a box of matches!
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