TIME: Less than 15 minutes

Do you like chemistry and visually exciting and spectacular experiments? Here we suggest a very curious experiment that you will be able to display in your living room and impress your guests!

We will make a homemade lava lamp using very simple materials.

What do you need?

• A transparent 2-litre plastic bottle, empty and clean
• 3 cups of sunflower oil
• Vegetable liquid coloring
• A funnel
• Effervescent tablets

Steps

1. First you need to fill the bottle to ¼ of its capacity
2. Next use the funnel to fill the bottle with 3 cups of sunflower oil
3. Next add 5 drops of vegetable coloring of your favourite color
4. Finally add two effervescent tablets and put the lid on the bottle

Experimenta

• What is the reaction when we mix water and oil? What happens with both liquids?
• What happens when you add the coloring to the mix?
• How does the mix react when you add the effervescent tablets?

L'explicació del científic
It’s an incredible experiment, isn’t it? We really like it, but do you know what happens exactly inside the bottle? In the first part of the experiment, when you mix oil with water inside the bottle, these two liquids separate themselves: the oil stays on top, and the water goes to the bottom, because they have different densities. When you add coloring, you can see the color drops go to the bottom because coloring has a higher density than oil. Finally, when effervescent tablets are added to the mix, they start to generate gas (carbon dioxide), that is less dense than water and oil, and therefore it rises to the top. On its way to the surface, the gas drags little water drops that have already been dyed with the coloring, and they produce an amazing visual effect. When they reach the surface, the gas escapes the oil and the water, and coloring drops (that are denser than oil drops) fall towards the bottom of the bottle. This process happens repeatedly until the effervescent tablets dissolve completely.