Bubbles are fascinating: The spherical shape, the sheen and the rainbow colours, the way they float and move with the air currents… They are a source of wonder; but how do they form? What makes them pop? What holds them together? AND can you blow bubbles on the Moon?
What do you need?
Bubble mix, pipe cleaners or bubble wands
Where to start
Blow a few bubbles! Try blowing harder or using a bubble mix with a different consistency – does it make a difference? How long does your bubble last? What makes it pop? What do the children think? You could film one or two children blowing a bubble and show it in slow motion. Watching the soapy water expand may start a conversation about how the bubble forms. What shape is the bubble and does the shape vary? If you make a square bubble wand with a pipe cleaner, will you get a square bubble?
What’s the STEM?
This is an investigation into air, which will help the children understand that it is a substance – not just nothing! As you blow a bubble, you are filling a ‘bag’ of soapy water with air. As the soap bubble fills, the pressure of the air outside the soap bubble pushes back. This stops the bubble from immediately bursting. If you were blowing bubbles in the vacuum of space or on the Moon (which would be pretty hard to begin with), there would be no air to push back on the outside of the soap bubble so it would burst straight away.
However, if you were blowing bubbles in the International Space Station, the bubbles may last longer than on Earth. There is air in the space station but no gravity. As the soap bubble floats on Earth, the soapy water is affected by gravity. It sinks to the bottom of the bubble and the soapy film at the top of the bubble gets thinner and thinner until the bubble bursts. The space station bubble wouldn’t be subject to gravity so it wouldn’t burst so quickly.
The shape of bubbles is very interesting as well. Soap bubbles form spheres because a sphere has the largest volume of air to the smallest amount of surface area (or bubble mix). A soap bubble will only take a different shape if it is touching something other than air.
You could have a look at our videos on how to make a bubble snake, and the shape of the bubble in a washing up bowl. You could also do some bubble printing. If you are interested in exploring the space theme, we’ve got some ideas for investigating how sound travels in the vacuum in space compared to on Earth.