Science Smarts: Create your very own lava lamp
By Patty Rooks on May 1, 2021.
This week I have been doing a lot of research for our next Zoom Science evening with the Redcliff Public Library. These evenings are sooo much fun and the next one is a bit special as we will be celebrating the week of Science Odyssey in Canada.
On our Zoom science evening, we are very fortunate to have a local STEM expert talk about his work involving explosives and then we are going to do some of our own explosive hands on science together! Of course, we have to celebrate all week long and this is only one of many activities we have planned in order to help celebrate Canada’s Science Odyssey which runs May 1-16 this year. In case you cannot make our Zoom evening, I thought I would share a sneak peek at one of the activities we may be doing that week.
Let’s get started!
Remember to ask an adult before doing this experiment.
Materials
• Empty clear jar, bottle or container
• Vegetable oil (the cheaper the better)
• Food colouringÂ
• Alka-Seltzer tabletÂ
• Water
Procedure
• Fill the bottle 3/4 full of vegetable oil.
• Carefully pour in some water until the bottle is almost full, not overflowing.
• Slowly add about 10 drops of food colouring. Be sure to make the water fairly dark in colour.
• Make some science observations. Do you notice that the food colouring only colours the water and not the oil?
• Open the package of Alka-Seltzer. Have an adult help you divide the Alka-Seltzer tablet into eight pieces.
• Drop one of the tiny pieces of Alka-Seltzer into the oil and water mixture. Watch what happens. When the bubbling stops, add another chunk of Alka-Seltzer. It’s just like a lava lamp!
• When you have used up all of the Alka-Seltzer and the bubbling has completely stopped, screw on the soda bottle cap. Tip the bottle back and forth and watch the wave appear. The tiny droplets of liquid join together to make one big lava-like blob.
How does it work?
First of all, you confirmed what you already knew … oil and water do not mix. The molecules of water do not like to mix with the molecules of oil. Even if you try to shake up the bottle, the oil breaks up into small little drops, but the oil doesn’t mix with the water. Also, food colouring only mixes with water. It does not colour the oil.
When you pour the water into the bottle with the oil, the water sinks to the bottom and the oil floats to the top. This is the same as when oil from a ship spills in the ocean. The oil floats on top of the water. Oil floats on the surface because water is heavier than oil. Scientists say that the water is more dense than the oil.
Here’s the surprising part … The Alka-Seltzer tablet reacts with the water to make tiny bubbles of carbon dioxide gas. These bubbles attach themselves to the blobs of coloured water and cause them to float to the surface. When the bubbles pop, the colour blobs sink back to the bottom of the bottle. Now that’s a burst of colour! Your own homemade lava lamp … groovy baby
Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismedhat.com, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403.527.5365, email: praxis@praxismh.ca.
