(or Happy New Year!)
Thursday (3rd February) will be the start of the Chinese New Year.
On this night will be a full moon (good night for moon-watching) and the celebrations will end 15 days later when the lunar cycle is halfway through and there will be a new moon (not such a good night for moon-watching).
This day, 17th February is when the Lantern Festival takes place and during this night some people will let loose sky lanterns. Traditionally, people would write messages on them and hoped they would reach the sky god who would make their wishes come true.
This video of sky lanterns gave me some ideas for lessons.
The simplest idea would be to show the video and ask students to explain why the lanterns float upwards. This would be a good plenary to a lesson on convection as students can apply what they have learnt about why hot air rises to explain what is happening. They can get a lot of science into an explanation such as this and gives students an opportunity to link the key ideas of particles, energy and forces.
For a bit more of a wow factor you could demonstrate the ‘flying teabag’ experiment. (see weblink below for a video). I think this is an ideal start to a lesson on convection and you can follow this by asking the students to come up with their initial ideas on how it happens. As a plenary they can go back to their original explanation and improve on it using what they have learnt in the lesson.
If you are looking for a longer project, why not get a class to make their own sky lanterns which they can then set off in their own lantern festival? The ‘full of hot air’ video shows a method of how to make a hot air balloon out of tissue paper (which is essentially the same thing as a fire lantern) and also contains a nice animation which explains how hot air balloons work.
I have used a tissue paper balloon as a demonstration in the past and the students always loved it. I heated the air inside by very gingerly holding the balloon over a (very small) Bunsen burner flame and surprisingly, given my propensity for clumsiness, it never caught fire once. I agree that a roomful of teenagers doing the same thing is an altogether different ball game so you may wish to use the safer method of using a hair-dryer!
Full of hot air video
Video which shows how to do the flying teabag demonstration