Magic Rainbow Water!

Filed in Mad Scientist Activites by on 01/12/2017 0 Comments

Magic Rainbow Water

Let’s learn about density!

Ask your adult assistant to help you find somewhere to set up your science lab. Protect surfaces and clothing as appropriate before undertaking science experiments. Safety glasses are recommended to protect eyes from splashes, as needed.  Adult supervision is required at all times whilst undertaking experiments.

 

You will need cups of colored water (red, orange, yellow, green, blue and purple (check out our color mixing experiment here), with around a cup of colored water in each, around a cup of sugar, a spoon (to stir), your test tubes and your pipette.

 

Part 1 – Dissolving! Making a solution

Take a minute to talk about what you’re going to do. Now write down your hypothesis in your notebook. What’s going to happen when you add sugar to the water?

Set out your colors in the following order (a great opportunity to  discuss what colors are found in the rainbow):  red, orange, yellow, green, blue and purple.

Add the following number of heaped teaspoons of sugar to each cup of colored water:

Red (zero), orange (2), yellow (4), green (6), blue (8), purple (10).

Now get stirring! Stir each one with your spoon until all (or almost all) the sugar has dissolved. Congratulations you’ve made a solution! Actually several solutions. Well done!

 

Part 2 – Making a Sugar Water Rainbow

 

Using your pipette (this is great for fine motor skills but a younger child may need to be shown how to squeeze the bulb to draw up the liquid) draw up some of the purple sugar solution.

Note: This solution might be super sticky because of the high sugar content.

Squeeze the pipette into a test tube.  Repeat this two or three times. Now do this again with the blue, green, yellow, orange and red.  To get the best results pipette the solution carefully into the test tube by adding it gently near the surface or running it down the side of the test tube. Hold it up to the light…. what’s happened?

 

The Science Behind It

As you add more sugar to the colored water, the sugar dissolves, making the water more dense (which makes it heavier than the solutions with less sugar added). The cup containing the 10 teaspoons of sugar will be the most dense, the cup with no sugar will be least dense.

You put the most dense solution, with 10 teaspoons of sugar, on the bottom.

Why do you think that is?

What will happen if you try it with the least dense, red solution, on the bottom?

What happens if you gently shake the test tube?

 

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