Bouncing Bubble (Andrew Salg)
Author
Andrew Salg
Principle(s) Illustrated
Surface tension
Elemental Bonding
Standards
HS-PS2-3 Apply scientific and engineering ideas to design, evaluate, and refine a device that minimizes the force on a macroscopic object during a collision.
HS-PS2-4Use mathematical representations of Newton’s Law of Gravitation and Coulomb’s Law to describe and predict the gravitational and electrostatic forces between objects.
HS-PS2-6 Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
Questioning Script
Materials Needed:
A measuring cup
1 cotton glove
1 cup of distilled water
2 tablespoons of dish soap
1 tablespoon of glycerin
Bubble wand
Prior knowledge & experience:
The students should already know what a soap bubble is composed of, and that bubbles do pop when coming into contact with some objects. Students also know that bubbles can be big or small depending on how much solution with water and air is mixed. The students also should know that there are various types of solutions used to make bubbles and their functions. Dish soap is made for cleaning dishes. Bubbles for playing with and taking baths with.
Root question:
What do you think is going to happen when I touch the bubble using a glove?
Target response:
The bubble will not pop, this is because the bubble is not coming into contact with chemicals that can break the bubble. Dirt and oil from a person's bare hands can pop a bubble, but because our skin absorbs the water content from the bubble. Bubbles are made from a mixture of soap and water, and the water helps hold together the soap molecules. The tension on the surface of the bubble is high, and removal of the water breaks the chain, causing the bubble to burst.
The glycerin that is added in the mixture strengthens the bubble by bonding with the water. The glycerin is either made from fats and lipids, or propylene products. The glycerin with change the chemical makeup of the bubble solution resulting in a stronger bubble.
Common Misconceptions:
Students will often think that the bubble will pop because it is coming into contact with an object.