Wednesday, May 21, 2014

Bubbles: Experimenting with the Reaction of Oil, Water, and Alka Seltzer

Most kids think of bubbles being formed by dipping a wand into bubble solution and blowing, but bubbles are formed by many different causes in nature such as waves crashing into rocks.   Another way bubbles can be formed is during a reaction and a simple experiment to visualize this was posted at Little Hands for Little Bins.  This experiment involves reacting Alka Seltzer, water and oil to make colored bubbles in a glass and is a great extension to the other bubble activities from our Bubble BLAST.

The supplies you need to conduct this experiment (oil, water, Alka Seltzer and food coloring) are easy to find and good chances you have them around the house already.  Which makes this a great experiment to do when you are looking for something to keep little minds busy.

First, we poured the oil into the container filling it about 2/3 of the way up.  Jelly Bean is focused on pouring just the right amount of oil.  

Then we added the water.  The the girls had fun watching the oil and water separate as they poured. The girls expected the layers to form since we learned about different densities in our Float-Sink BLAST

Next, we added the food coloring.  The girls just squeezed several drops in and did not mix the solution.  It was neat to see the food color stay little colored blobs.  Since we had both liquid food coloring and gel food coloring, we decided to test both.  Jelly Bean is using red gel food coloring, and Jumping Bean is using green liquid food coloring. 

After dropping pieces of Alka Seltzer into the water and oil mixture, bubbles started to form.  The exciting part was that colored bubbles rose up through the oil!  Both food colorings (gel and liquid) worked well, but we thought the green food coloring was easier to see.

Jelly Bean and Jumping Bean loved watching the bubbles form in the water and oil, but I think they had even more fun shaking their containers at the end and watching the mixture settle into their natural layers. 
What happened in this experiment:  First, we explored how oil and water do not mix and separate into different layers.  We also saw that the food coloring passed through the oil and settled in the water layer.  Second, we dropped the Alka Seltzer tablet into the water where it reacted to form carbon dioxide bubbles.  As the bubbles rose to the surface they would carry bits of food coloring with them (like we saw with the dancing raisins).  At the surface, they would pop and the food coloring would sink back down through the oil to the water layer.

  • clear container (we used a mason jar and a lid is not required unless you want to shake the mixture to watch it settle to its natural layers after the Alka Seltzer has finished bubbling)
  • water
  • oil
  • Alka Seltzer
  • food coloring
  1. Pour oil into the container- about 2/3 full.
  2. Pour water into the container until it is almost full.
  3. Watch as the water and oil separate.
  4. Add drops of food coloring.
  5. Break up 2-3 Alka Seltzer tablets into small pieces.  Make sure you do not have the lid on your container at this point - it could become explosive with the lid.  
  6. Drop pieces of Alka Seltzer into the container.
  7. Watch as colored bubbles float to the top and sink back down to the bottom.

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