They added vegetable oil, water and food colouring to a container and then added some fizzing tablets (Alka Seltzer). They then watched in awe as they saw the tablet effervesce and the lava lamp effect begin!
"It was so cool, I was scared it was going to erupt like a volcano!" Bayleigh, Sequoia
The children learnt that firstly the oil and water cannot mix because of "intermolecular polarity". This means that the molecules in water and the molecules in oil do not bond together. We discussed that when oil is dispersed into water it creates an emulsion. The children learnt that this is how ice-cream, butter and even mayonnaise is made!
"I wasn't sure if the oil and water would separate again, but they did because it's an emulsion." Archie, Sequoia
After the children added in the tablet, they saw it sink to the bottom as start to dissolve. This created bubbles and, as they rose to the top, they took some of the coloured water with them.
This is a fun demonstration that can be easily done at home and I'm sure the children would love to show it to you! As it is Science week, we also discussed some potential research questions for the children to find the answers to at home. That way, you can turn the demonstration into a scientific experiment!
"What if you added two tablets at once?" Ruben, Sequoia
"Would it be different if you used warm water instead of cold water?" Sabeer, Sequoia
If you would like to try this at home please click here to find out what you need and how to do it.
Please send in some pictures if you do carry out the experiment at home and we would love to find out the answers to those questions!
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