The heat source at the bottom of the lamp liquefies the waxy blob. As it expands, its density decreases and it rises to the top—where it cools, congeals and begins to sink back down. In , he sold the U. They appeal to people at ease in darkness. Yet the sleek, rocket-like exterior was perfectly pitched to the space age.
Science Bob. Download the PDF. The Magic Ketchup Experiment! New Zealand students study density with Blobs In a Bottle. Make Some Ghost Bubbles! ADS these ads support our free website. It was messy, but it was fun! Oil floats on water because a drop of oil is lighter than a drop of water the same size.
Another way of saying this is to say that water is denser than oil. Density is a measurement of how much a given volume of something weighs. Things that are less dense than water will float in water. Things that are more dense than water will sink. Even though oil and water are both liquids, they are what chemists call immiscible liquids. That's a fancy word that means they don't mix.
Salt is heavier than water, so when you pour salt on the oil, it sinks to the bottom of the mixture, carrying a blob of oil with it. In the water, the salt starts to dissolve. As it dissolves, the salt releases the oil, which floats back up to the top of the water. Then pour in the colored water until the liquid in the cup is about inches from the top. Well, unless you want to turn it into an eruption experiment too.
For this reason and quick cleanup, I like to do this on a tray. Let the children take turns adding a piece of an Alka Seltzer table to the cup. The Alka Seltzer reacts with the water to make bubbles of carbon dioxide.
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