Have you ever seen a lava lamp? They're basically an ongoing chemical reaction in a bottle! They were a big hit in the past, and people would buy them to add some fun light and a mesmerizing visual to their room.
In this month's 20 Minute Lab, we'll use some household items to make our own lava lamps!
This experiment is great because it's fun day or night (with a little flashlight help), and you can use the 'lamp' over and over again!
Note: make sure NOT to drink or taste your lava lamp - it's would taste gross and wouldn't be good for your body!
(Notice how you can just keep adding pieces of tablet to keep the lamp going!)
What's going on?
Before you put your tablet in the mix, you poured the colored water into the oil. Did you notice how the water went straight to the bottom?
That happened because water molecules are smaller than oil molecules, so they can pack more tightly together. This means that water is denser than oil.
It's sort of like the difference between sand and marbles - sand (like water) is made up of tiny bits, and marbles (like oil) are made of big bits. And you know that you can pack more sand into an area than marbles!
Water and Oil Don't Mix
Water doesn't mix with oil because oil is made of 'hydrophobic', or water-fearing, molecules that want to keep away from water. The food coloring, on the other hand, mixes well with water and dissolves into it (notice how the oil stays the same color).
Alka-Seltzer has sodium bicarbonate and citric acid in it. When you put the tablet in water, a chemical reaction occurs: the sodium bicarbonate and citric acid molecules bump into each other, swap parts, and form new molecules. One of those new molecules is carbon dioxide.
The fizzing action is actually bubbles of carbon dioxide gas. The bubbles rise to the top of the glass, and as they do, they attach to globules of colored water and bring them up to the top as well!
Once they reach the top, the bubbles burst, leaving nothing to keep the dense blobs of water from sinking again.
Keep experimenting!Try these variations to keep the fun going:
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