ready steady science... making bubbles
what you’ll need:
• Straws – plastic bar straws are the best to make frames out of, but drinking straws are the best for blowing bubbles.
• String
• Pipecleaners
• Soap Solution (Washing up liquid / glycerine / water)
• Water pistol or plant sprayer
• Washing up bowl
• Scissors
what to do
• Make a soap solution with washing up liquid (10%), water (89%) and glycerine (1%). Mix carefully – and don’t whisk it or you’ll get lots of small bubbles appearing that make blowing larger ones difficult.
• Use a simple hoop of wire to test out your bubble mixture.
• Use the water pistol to moisten the air.
• Now design different hoops to make a square bubble – can you do it? (Six bubbles together yield a square bubble in the centre). If not, go for the big finale and make one huge bubble.
different dippers – for advanced bubblers
The basic wire loop - Take a short piece of pipecleaner and form a loop in it about 4 cm in diameter. Dip into the bubble solution and gently blow.
Drinking straws make fairly good bubble blowers. They will hold more bubble juice if 4 short slits (about 5cm) are cut at the bubble end. The resulting tabs should splay out.
The big bubble loop - Slide two drinking straws onto a piece of string about 1m long. Tie off the ends to form a loop. Hold the straws apart to form a big rectangle. Bring the straws together to close the rectangle and dunk it into a bucket of bubble juice. Pull it out again and slowly separate the two straws. A film should form around the loop. If it doesn't break, pull the loop through the air to form a giant bubble.
Make frames - Form frames using the drinking straws for the straight pieces. Connect two straws at a corner by inserting a doubled-up pipe cleaner into the end of each straw. In places where three straws meet, fold the pipe cleaners three ways. Attach a pipe cleaner handle to your frame.
Other ideas: Try constructing cubes or tetrahedrons, or just let your imagination run wild. Mix the soap solution in the bucket. Make sure that you have enough solution to fully cover the frames when they are dipped.
Dip the frames into the soap solution, and observe the fascinating geometrical shapes that the soap films form. Also notice the shimmering colours in the soap film.
what’s happening?
The Shape: As you lift your frame out of the solution, the soap film flows into a state of minimum energy. The soap film is in this state of minimum energy when it's covering the least possible amount of surface area. The intricate shapes you see inside the frame represent the minimum area the soap film can cover. You may notice that a soap film will sometimes take on different shapes when you dip the frame into the solution again and again. That's because there may be more than one way for the soap film to form a minimum surface area.
Those rainbows: Bubbles consist of two thin films of soap with water in between. When white light (which contains all the colours of the rainbow) hits the soap films, it will be reflected back, but is sometimes spread out into a spectrum (or rainbow). When two sets of reflected waves meet, they can add together, cancel or partially cancel each other out depending on the thickness of the film and the initial colour of the light. When light waves of a particular colour meet and cancel each other, then that colour is subtracted from white light. For example, if the red light waves cancel, then you see white light minus red light, which you perceive as blue-green light.
Bubbles – so clear, and yet so colourful…
<< Go Back