• Food colouring
  • Effervescent (fizzy) tablet or salt

PARENT TIP:

This experiment can be repeated many times by simply dropping in more tablets/salt. However, when you do want to dispose of the oil, because of the chemicals dropped in you should wait for any remaining tablet to completely disolve away, screw the lid on tightly and throw it away. I wouldn't recommend trying to re-use the oil for cooking purposes. If any tablet/salt has not finished disolving before you screw on the lid the gas will build up inside the jar and if there is enough the jar could explode.
  • A jar
  • Water
  • Vegetable oil

WHAT YOU NEED: 

  1. Pour a little water into the jar and add some food colouring.
  2. Fill the jar with vegetable oil, until it is 3/4 full.
  3. Now just add pieces of the effervescent tablet, or salt (I like to use vitamin C tablets) and watch as the bubbles form.
 
Tip: Make sure that when you are adding the oil you run it down the inside of the jar slowly to prevent bubbles forming between the water and oil layers. If you do get bubbles forming if you leave the lava lamp to sit still for a while they should disapear.
 

INSTRUCTIONS: