Here are easy instruction to make a bubble print picture. A bubble print is a sort of bubble fingerprint that uses water-based paint to capture the structure of soap bubbles on paper. The project is a fun art activity, plus it’s a great science project. Bubble prints are a record of the shapes bubbles make when they merge. Mixing colors of paint is an entertaining way to explore color chemistry.
Bubble Print Materials
You need deeply-colored bubbles to capture them on paper. Tempera paint powder works very well, but you can use any water-based paint, like liquid water colors or acrylic paint. Avoid oil-based paint because oil disrupts bubble formation. You will need:
- Bubble solution (buy it or mix water, dishwashing liquid, and a bit of glycerin)
- Tempera paint or watercolors
- Small plates
Make Colored Bubble Solution
The goal is to make the most colorful mixture possible, while still being able to blow bubbles.
- Pour a bit of bubble solution onto the bottom of a plate.
- Stir in paint.
- Test it by trying to froth up the mixture by stirring or blow into the liquid with a straw to see if you get bubbles.
- If you don’t get enough bubbles, add more bubble solution to the mixture.
You don’t need a lot of bubble solution and paint for a plate, so you can make many plates of different colors, if you like.
Make Bubble Prints
- Use a straw to blow into the liquid so it bubbles up. If you only have a little liquid on the plate, tilt the dish to make it easier to blow bubbles. Experiment with your technique to see the results you get with a few larger bubbles versus numerous tiny bubbles.
- Touch the bubbles with a sheet of paper. You don’t need to press into the bubbles with the paper. Lightly touch the bubbles and they leave imprints when they pop.
- You can switch colors. Either use different colors of paint on separate plates or add two colors to bubble solution but don’t mix them. Blowing bubbles into unmixed paints forms interesting multicolored shapes.
Glowing Bubble Prints
The same technique works for bubble prints that glow in the dark or under black light. The only difference is the pigment or paint that you use.
- To make bubble prints that glow under black light, use tonic water that contains quinine in place of paint. Regular tonic water works better than sugar-free tonic water because the sugar in the regular product makes the bubbles sturdier. The bubble print will dry invisible, but will show up under black light. If you want the print to appear under normal light, add a small amount of colored paint. Don’t use too much colored paint or it will mask the glow.
- To make bubble prints that glow in the dark, your best bet is mixing glow powder with bubble solution. Expose the bubble print to bright light and then turn out the light to see the glow. Water-based glow paint also works, but avoid any oil-based paint because it makes it hard (or impossible) to blow bubbles.
Bubble Print Science
Soap bubbles take the shape that minimizes the surface area needed to enclose a volume of air. So, a single bubble forms a sphere. German mathematician Hermann Schwarz showed the sphere as the least-area method of enclosing volume in 1884, but it wasn’t until the year 2000 that scientists proved merging soap bubbles also used the optimal method of enclosing different volumes of air. A mass of bubbles contains hexagonal cells, much like the cells of a beehive. Ideally, three bubbles meet at 120° angles, but the perfect situation doesn’t apply to real-world bubbles because they are different sizes (volumes) and thicknesses. You can see the way two, three, or a mass of bubbles merge in a bubble print.
Mixing paints for bubble prints is an exploration of color. If you start with primary colors, you can mix them to get secondary colors:
- Green = Blue + Yellow
- Orange = Yellow + Red
- Purple = Red + Blue
- Hutchings, Michael; Morgan, Frank; Ritoré, Manuel; Ros, Antonio (July 17, 2000). “Proof of the double bubble conjecture”. Electronic Research Announcements. 6 (6): 45–49. doi:10.1090/S1079-6762-00-00079-2
- Teixeira, M.A.C.; Teixeira, P.I.C. (2009). “Contact angle of a hemispherical bubble: An analytical approach”. Journal of Colloid and Interface Science. 338 (1): 193200. doi:10.1016/j.jcis.2009.05.062