🧪 Science with Sarah: Baby oil lava lamps 🌋💡

A heat-free way to see mixtures, solutions, and density at work

👉 Watch the video of Sarah’s school science experiment here!

Hello parents, teachers and students! If you’re looking for a fizzy, fun experiment, look no further! Making these baby oil lava lamps will teach your students about mixtures, solutions, and density.

Be sure to check out GMSA@9 on Wednesdays when Meteorologist Sarah Spivey does the demonstrations and explains the science behind it.

Science with Sarah: Invite KSAT to your school for live science experiments. (KSAT)

HERE’S WHAT YOU’LL NEED

Baby oil lava lamp materials (Copyright 2022 by KSAT - All rights reserved.)
  • Clear plastic or glass bottles (smooth sides preferred). For fun, I used an Erlenmeyer flask to make this experiment look more science-y 😉
  • Baby oil
  • Water
  • Food dye
  • Alka-Seltzer tablets

DO THE EXPERIMENT

  • STEP 1: Fill the bottle about 3/4 the way with baby oil
  • STEP 2: Add some water and watch it sink to the bottom
  • STEP 3: Put a few drops of food dye into the bottle. The dye should sink to the bottom and mix with the water
  • STEP 4: Add an Alka-Seltzer tablet to the bottle. The gas should cause the colored water to rise and bubble up throughout the baby oil
Baby oil lava lamp! Here's what it should look like. (Copyright 2022 by KSAT - All rights reserved.)

HOW IT WORKS

This is a good example of solutions, mixtures, and density.

DENSITY: The water and food dye are more dense than water, so they sink to the bottom of the bottle.

MIXTURE: Water and oil do not mix into a solution, so the colored water stays separate from the baby oil. Thus, the baby oil and the colored water form a mixture, rather than a solution.

SOLUTION: The Alka-Seltzer tablet contains sodium bicarbonate and citric acid which produces carbon dioxide gas when mixed with the colored water.

SCIENCE WITH SARAH

If you’d like Sarah and David to come to your school and conduct a science experiment live on KSAT, email sciencewithsarah@ksat.com.

Parents and guardians: upload a video of your child performing the activity by clicking here. Send it in and you might see it on GMSA @ 9 a.m.!


About the Authors:

Sarah Spivey is a San Antonio native who grew up watching KSAT. She has been a proud member of the KSAT Weather Authority Team since 2017. Sarah is a Clark High School and Texas A&M University graduate. She previously worked at KTEN News. When Sarah is not busy forecasting, she enjoys hanging out with her husband and cat, and playing music.

Ben Spicer is a digital journalist who works the early morning shift for KSAT.