MA STEM Week: Lava Lamps

Grab a few household supplies and give this lava lamp science activity a try! Your kids will love exploring colored water and oil, but a surprise ingredient will make this science activity even more exciting!⁠
Clean plastic water bottle, oil (vegetable, baby, etc), food coloring, and an antacid tablet (the fizzy kind you drop in water).⁠
1. Pour water into the bottle until it’s about 1/4 full.⁠
2. Fill the rest of the bottle with oil allowing for some empty space at the top.⁠
3. Wait for the water and oil to separate. You need to have two distinct layers, so make sure little hands don’t shake the mixture!⁠
4. Once the layers have formed, add a dozen or so drops of food coloring to the bottle. Observe how the food coloring falls through the oil and mixes with the water.⁠
5. Break the antacid tablet into smaller pieces and drop one of them into the bottle. You’ll notice it begins to fizz causing the colored blobs start to float and dance around! When the blobs stop moving, add another piece of the antacid tablet and enjoy the dance again. As difficult as it is, try not to let kiddos shake the bottle because you’ll end up with a very muddy mix.⁠
The oil floats on top of the water because it is less dense and lighter than water. The food coloring has the same density as the water so it sinks through the oil and mixes with the water. When you add the tablet it sinks to the bottom then starts to dissolve. As it dissolves it makes gas called carbon dioxide. This gas is lighter than water so it floats to the top. The air bubbles bring some colored water with them to the top. When the air comes out of the colored water blob, the water gets heavy again and sinks. It does this over and over again until the tablet is completely dissolved.⁠
What happens if you put the cap on after dropping in the fizzy tablet? What happens if you drop a whole tablet in the bottle? Try sprinkling some salt into your lava lamp instead of the tablet. What happens?⁠
We hope you enjoyed our STEM week activities! Thank you so much to our STEAM Education Partner, National Grid, for sponsoring these STEM activities all week long.

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