top of page

Rainbow in a Jar

DSC05063.JPG

How can you stack the liquids? 

Look at this picture! This is the rainbow I made. It's beautiful, right? But how can I stack the liquids? To understand this scientific activity, you need to learn about liquid density. Follow me to make your own rainbow in a jar and learn the secret of stacking the liquids.

 Materials

  • water

  • dish soap

  • corn syrup

  • vegetable oil

  • rubbing alcohol

  • food coloring

  • a bottle to put your rainbow in

rainbowinabottle.jpg
youtube-g7926e4df2_1920.png

 Procedures

  1. Take the liquids and separate them into small containers.

  2. Change the color of each liquid using food coloring to see the layers clearly. It is very interesting to watch how the food coloring moves in each liquid.

  3. Pour corn syrup into the bottle.

  4. Then add blue dish soap using a funnel.

  5. Add water using a stick. It helps to slow down when you pour water so that the colors don’t mix together quickly. Pour it slowly and gently.

  6. Add vegetable oil. Use a stick again.

  7. Lastly, add rubbing alcohol. I use a dropper. It takes time and a bit boring, but I highly recommend you to use this dropper. Watch the video and you'll see why.

Science Behind It

SBI_rainbow.jpg
youtube-g7926e4df2_1920.png

As you know if you put something heavy in water, it sinks to the bottom. And if you put something light in water, it floats to the top. Just like this heavy liquids sink to the bottom while light liquids float to the top. In science we use the word “more dense” and “less dense” instead of “heavier” and “lighter”. Liquids with higher densities sink to the bottom, while liquids with lower densities float to the top. But what makes different densities? It depends on what kind of molecules and how many molecules the liquid has.

​

Let’s compare water and oil. A water molecule consists of three atoms; an oxygen atom and two hydrogen atoms. An oil molecule mainly consists of hydrogen and carbon. Oxygen is heavier and smaller than carbon. So water molecules pack very close together and there are more molecules in water than at the same volume of oil. This makes water more dense than oil. Let me pour water into the oil and let’s see what happens. You can see water sinks to the bottom and oil floats on top of water. Let’s try one more thing. I will pour blue corn syrup which has the highest density among these three liquids. Corn syrup passes through oil and water and sinks the bottom due to liquid density.

bottom of page