Science: oil and water don’t mix, turned into a lava lamp

Last week we did a fun little experiment to illustrate the fact that oil and water don’t mix. I started with a little introduction about how water molecules are polar and oil molecules are non-polar and what that means and why they don’t mix as a result.  And that oil will always float on top of water because it is less dense (weighs less), which lead to a discussion about oil spills in the ocean and the negative impact on animals (with Rylan everything gets related to animals and/or conservation! :) ). 

As we discussed all the facts about, we moved through the steps of the experiment:

• add water to an empty, clean, clear bottle
  
• add a few drops of food coloring to the water for better visual effect

• Add (cooking) oil and shake well. Our mixture actually turned a light green, which doesn’t show well in these pictures.

 

• Watch as the water and oil separate again.

 

• After we completed this, for some extra fun, I gave the boys a few half tablets of alka-seltzer, which they took turns dropping into the bottle, so we could watch the water and oil move with the bubbles rising, like a lava lamp.