Bubble wall

The bar can be lowered into the soap solution reservoir and then raised to create a bubble wall.

<image to follow: layers in a bubble wall>

Bubbles can be created using a solution of a chemical called a surfactant. In this case, the surfactant is washing-up liquid. A bubble wall has 3 layers: a layer of water sandwiched between two layers of surfactant. One end of the surfactant is water-liking and faces the water layer, and the other end is water-disliking and faces away from water, into the air.

Bubbles can form different shapes depending on how they are formed; they can even be a wall.

Soap bubbles can be found in our everyday lives in the kitchen sink or in the bath.

Exploration Questions

Ask pupils the following questions as they explore the exhibit:

• What do you think the liquid in the reservoir is?
  Example answers: Soap, washing-up liquid, water.
   
• What shape of bubble do you think you can make with the exhibit?
  Example answers: Square, flat.
   
• What colours can you see in the bubble?
  Example answer: All the colours of the rainbow.

Activity

• What happens when you touch the bubble with a dry finger?
  Examples answer: It bursts.
   
• What happens when you touch the bubble after you have dipped your finger in the soap mixture?
  Example answer: It doesn’t burst, it’s less likely to burst.
   
• Why do you think the bubble eventually bursts?
  Example answer: Bubbles have a very thin wall that can be disrupted by being touched or the movement of air around it.