Lava Lamp
em Science
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Describing what density, polarity, viscosity, and solubility are and developing the child’s critical thinking and problem-solving skills.
Fill a glass or plastic bottle of the way with cooking vegetable oil. Fill the rest of the glass with water and observe what happens. What can you see?
Add drops of food colour to the mixture and observe. What do you see?
Put a little baking soda or Alka-Seltzer in the mixture and observe. Now what do you see?
When the liquids settle, observe the liquid fizz carrying the coloured water bubbles through the oil tank. Talk about your observations. What is happening at each stage?
Explain what happened to your child:
- Before the Alka-Seltzer was added to the bottle, the oil floated on the coloured water because it is less dense than water (density). Oil and water don't mix because water molecules are not attracted to oil molecules (polarity and viscosity).
- When the Alka-Selzer tablet was added to the oil and water, it sunk to the bottom because it is denser than oil and water. The tablet began to dissolve in the water and the chemicals in the tablet reacted with each other to create bubbles of carbon dioxide gas (solubility)