Liquid Lava Layers
Investigate density and create a home-made lava lamp effect.
This activity may be Messy and Stimulating
Investigate density and create a home-made lava lamp effect.
This activity may be Messy and Stimulating
What will I need?
Gather your supplies using the list above.
1.
Use the funnel to pour water into a clean bottle until it is one-third full. Add a few drops of red food colouring.
2.
Fill the rest of the bottle with vegetable oil.
3.
Break the vitamin tablet in half and add it to the bottle. Watch the lava bubbles!
- Try using a straw to blow bubbles into the layers. What happens?
- What effect does adding another vitamin tablet have?
- Try changing the order you put the water and oil in the bottle. Does it make any difference?
- What can you see happening?
- What directions are the bubbles moving in?
- Why does the water not mix with the oil?
This lava lamp effect works for two reasons. The first is that oil and water don’t mix. This is because water molecules are attracted to each other but not to oil. The other reason is because of density, which is how compact a substance is. Water is denser than oil, so the oil layer stays on top.
The vitamin tablet falls through the oil, and when it reacts with the water it produces bubbles of carbon dioxide gas. This gas floats to the surface because it is less dense than both the water and the oil, carrying some coloured water with it. When the bubbles pop, the gas is released, and the denser water sinks back down again.
The density of objects is really important in our everyday lives. Floats help prevent swimmers sinking because they are a lower density than water and so remain buoyant.
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