How To Make An Ocean In A Bottle
Make an Ocean in a Bottle. The science boffins are going to show us how to make a Cartesian diver. It is named after Rene Descartes, a famous French scientist, mathematician, and philosopher.
Step 1: You will need
- A clear plastic bottle - a big soft drinks bottle is best
- A funnel
- Some water
- A few drops of blue food colouring
- cooking oil - any type will do.
Step 2: Aim
The aim of this experiment is to see why oil and water cannot mix together.
Step 3: Method
Fill one third of the bottle with water. Add a few drops of blue food colouring and swish it around a bit until it's turned a dark blue colour. Top up the bottle with cooking oil. Use the funnel to make it easier. Put the lid on as tight as it will go. Tilt the bottle from side to side. The water and oil do not mix together, but instead they form layers. The oil floats on the water which makes it move like a wave.
Step 4: Conclusion
Why did this happen? Oil sits on top of water because oil is less dense. but some liquids with different densities can mix together. So why not these two? For liquids to mix together their molecules need to make new bonds with each other. The oil and water cannot mix together because water molecules have strong bonds between them called hydrogen bonds. The oil molecules are also held together by bonds, but these are of a different polarity to the hydrogen bonds, and the oil bonds are not strong enough to break the water's hydrogen bonds. So the water and oil molecules cannot join up with each other, keeping the water and the oil forever separate.