This is another density experiment, but can also work as an art project for cross-classroom curriculums. In this experiment you can create a rainbow in a single contained by varying the density of each liquid. You will need the following:
- 5 glasses (can be plastic or glass)
- Food coloring
Line up 5 of the glasses. In the first glass put 1 tbsp of sugar, in the second glass put 2 tbsp of sugar, third glass gets 3 tbsp sugar, fourth glass gets 4 tbsp sugar and in the fifth and final glass put no sugar. After the glasses are ready, put 3 tbsp of water into each of the first 4 glasses. If the sugar does not dissolve at 1 tbsp of water to each of the first four glasses and stir again. Next, put 2-3 drops of food coloring to each glass (first glass gets red, second yellow, third green and fourth blue). Now you are ready to make a rainbow. In the fifth glass, fill it one-quarter of the way with your blue solution. Next, gently layer the green solution on top of the blue. You can use a spoon to help cushion the liquid while you pour. Continue layering the yellow and then finally the red solution. There you go, a rainbow in a bottle.