GROOVY LAVA‐LIKE LAMP
Grade: 5 Strand: Matter and Material Topic: Properties of and Changes in Matter General expectation: Demonstrate an understanding of the three states of matter and of changes in state Specific Expectations: ‐ Describe changes they observe in the properties of materials when the materials interact with each other ‐Describe examples of interactions between materials that result in the production of a gas Materials •
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1 L plastic or glass bottle 750ml of water 250 ml of vegetable oil antacid tablet or powder food coloring Procedure • Fill the bottle 1/4 full with water • Add 5 drops of food coloring • Fill the rest of the bottle with vegetable oil • Divide the tablet into several pieces and drop them in the oil and water mixture or pour the powder in and observe the reaction • When all of the antacid has been used and the bubbling has completely stopped screw on the bottle cap. Tip the bottle back and forth and watch the wave appear. The tiny drops of colored water join together to make one big lava ‐like blob. Scientific Explanation • Oil and water are, immiscible, meaning they do not mix. The water which is more dense stays on the bottom and the oil which is less dense stays on the top. The food coloring is a water based substance so it will only mix with the water leaving the oil its original color. When you add the antacid it creates a chemical reaction resulting in bubbles of carbon dioxide gas. These bubbles trap some of the colored water inside and are much less dense then the water or the oil so they rise up to the top through the liquid layers. When the colored bubbles get to the top, the gas bubbles burst releasing the colored water which sinks back down again through the oil layer. ALTERNATIVE
Materials
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Clear jar with lid
Food coloring
Water
Glitter
Vegetable oil
Salt
Procedure
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Fill the jar 3/4 full of water.
Add drops of food coloring until you like the color.
Sprinkle in glitter for extra sparkle.
Fill the jar almost to the top with vegetable oil and let the mixture separate.
Pour salt into the jar until you see the cool lava lamp effects. Add more salt for
continuing effect.
Scientific Explanation
Salt is heavier, or more dense, than water, and sinks to the bottom. When you add the salt it
attaches to oil molecules becoming more dense than the water and sinks. When the salt dissolves
the oil returns to the top.
How does a Real Lava Lamp Work?
A real lava lamp works on the same principle of changing the density of something so it will
float and then not. It consists of two immiscible waxes, one slightly denser than the other.
The denser one is heated up by the lamp at the bottom, which makes it expand slightly, become
less dense so that it will float in the other one. So it floats to the surface - a bit like a hot air
balloon.
There it cools down, and sinks again, starting the process again.