Flying lemons
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Flying lemons
Parkside F
Download film (right-click)Demonstration , Physics , Secondary
Using fire to lift a lemon — but how does it work?
Director's Notes:
Team Parkside F write:
Experiment to show how a lemon can fly!
…which doesn’t tell us all that much, unfortunately. The team consisted of three year 8 students (ages 12-13) — and that’s all we know!
As ever, extreme care and supervision required to repeat experiments involving fire.
SciCast Notes:
More clear close-ups from Parkside, and a clear film overall with a very clean commentary. I’m particularly impressed at what the team have chosen to leave out. There are several things that are obvious — that the lemon floats, for example — that they’ve not wasted time telling us. They’ve also taken care to control the background as best they can, propping up a big sheet of paper to help hide a busy lab. There’s plenty of attention to detail in this film.
You can get some good physics out of this, too. There are all sorts of questions about why the water level rises: is it the oxygen being consumed by the matches? Is it the CO2 dissolving, as mentioned here? Is it that the flames heat the air in the glass, causing it to expand and bubble out, and the water level rises when the flames go out and the air cools and contracts again? Or something else?
What sorts of experiments might you do to test the various ideas?
— Jonathan