Concentric Domes

- 600 g water

- 200 g liquid dishwashing soap

- 100 g glycerin

- a straw

- a perfectly flat surface (glass, plastic or steel)

1. Wet the work surface
2. Insert the straw into the soapy solution, blow through the straw forming a bubble and place it on the wet surface
3. Insert the straw into soap, water well even the external part of the straw, then very gently insert the straw in the first balloon and blow forming a second balloon
4. Proceed in the same way a third time (act very carefully, so that each newly formed balloon touches the previous one)



So what's going on? Each balloon is positioned in the center of the previous
There is air inside the balloon, placing an air bubble moves the air of the previous one, which increases due to the  elasticity of the soap. During the experiment, especially in case of failures you will remember how many compositions you can do with such balloons supported on a surface and you will also check the limit of expansion for the soap mixture.