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Type
science_lab
Pre Lab
Background: Have you ever tried to touch a bubble without popping it? Normally, bubbles pop almost instantly when they contact a dry surface or your skin. But with the right mixture, you can make bubbles that are surprisingly tough — sometimes called 'unpoppable' bubbles. The secret lies in understanding **surface tension** and the chemistry of your bubble solution.
**Surface tension** is the tendency of water molecules to stick together at the surface, forming a thin, elastic-like skin. A soap bubble is actually a thin film of soapy water with air trapped inside. The soap molecules lower the surface tension of water just enough to allow the film to stretch and form a sphere, but regular soap-and-water bubbles dry out and pop very quickly. This is where **glycerin** comes in. Glycerin is a thick, syrupy liquid that acts as a humectant — it attracts and holds onto water molecules. When added to a bubble solution, glycerin slows down evaporation, keeping the bubble film moist and flexible for much longer.
Some bubble solutions also take advantage of **polymers** — long chain-like molecules that add strength and elasticity to the bubble film. Dish soap itself contains polymer-like surfactant molecules, but adding extra substances like glycerin or even corn syrup can reinforce the film further. In this open inquiry lab, you will act as a scientist and engineer to design and test your own bubble solutions by changing the amount of glycerin used. You will measure how your **variable** — the amount of glycerin — affects how long bubbles last and whether they can survive being touched.
Vocabulary
Term: surface tension
Definition: The tendency of water molecules at the surface to stick together, creating a thin, elastic-like layer.
Term: polymers
Lab Type
Post Lab
Standards
Safety Level
Teacher Notes
Estimated Time
Experiment Design
Research Question
Learning Objectives
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