The idea that liquids can have different densities can be a very abstract idea for a preschooler to grasp. However playing with different liquids in a fun way can be a great way to explore and develop an intuition for the concept. At least they will learn that not all liquids mix together (like paint). This is a great stand alone activity or is an optional activity to reinforce the ideas explored in the float-sink blast (which introduces the idea of liquid densities).
To play with the idea of liquids having different densities we used oil, vinegar and water. Vinegar and water have very similar densities and will mix while oil has a lighter density and won't mix.
We started with multiple small containers filled with either vinegar or water. We colored them with food coloring just for fun. In larger containers we had water or oil. Bug started by pouring pink (her favorite into the first container)
She was so excited to see what would happen! The pink just became more diluted in the water. We repeated with the next container of water by adding vinegar and the same thing happened. It became more dilute as well.
She realized the oil container looked different and so she was very excited to pour something in here.
Needless to say she was totally fascinated when the vinegar balled up under the oil. I think her first thought was that the green liquid was something special as she immediately poured it into the first pink water container.
The pink and green mixed together and made "brown" which was not so exciting but still fun. She then asked if she could add some baking soda to the oil with the green.
She waited with excitement as the baking soda sank through the oil and onto the vinegar where....
... it began to fizz!!!
and form "flowers" as the bubbles rose to the surface.
She then began to play mixing different combinations.
Which either diluted colors or made new colors.
Of course we have to add baking soda!
and watch it bubble up! She quickly caught on that the more purple (i.e. added more blue vinegar) she made her combination the more it would bubble up!
She loved to hear the fizzing and would often put her ear near the surface. The bubble spray would tickle her face making for a great multi-sensory experience.
Good old oil and water looked a little plain and boring next to all the bubbling excitement.
Even daddy could not stay out of the fun and soon was helping to make even more bubbles.
Bug probably played with this for over 40 minutes and did not want to stop. Overall this was a great multi-sensory experience allowing us to see how colors changed when mixed, hearing and feeling the results of reactions, and provided for a fun chance to introduce new vocabulary like diluted or concentrated and density.
- baking soda
- food coloring
- Take two small containers, one with water and one with vinegar, and add food coloring to color.
- Add water to two larger containers (filled 1/3)
- Add oil to two more larger containers (filled 1/3)
- Allow the child to pour different amounts of colored liquids into the different containers.
- Encourage the following combinations:
- water and water (dilutes)
- water and vinegar (dilutes)
- water and oil (water sinks to the bottom)
- water and oil (vinegar sinks to the bottom)
- Take a spoonful of baking soda and add it to each one combination. Only those with vinegar will react.
- Allow the child to play and explore. What will happen if they add more vinegar to the water (hint the color gets darker and there will be more bubbles - signs that there is more vinegar).
- Encourage the child to guess what will happen before each step - encouraging the formation of hypotheses.