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🧪 Science with Sarah: Rainbow sugar density towers 🌈🍬

Learn the concept of density with syrupy sweet goodness

👉 Watch the video of Sarah’s science experiment at Bob Hope Elementary School here!

Hello parents, teachers and students!

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 in partnership with the San Antonio Zoo (Copyright KSAT 2023 - All rights reserved)

HERE’S WHAT YOU’LL NEED

  • 7 clear cups
  • Sugar
  • Water
  • Food dye
  • Tablespoon
  • 1 cup measuring cup
  • Spoon
  • Permanent marker
  • Syringe or dropper

DO THE EXPERIMENT

  • STEP 1: Take 6 of the clear cups and label them with these numbers: 0, 2, 4, 6, 8, 10
  • STEP 2: Fill each cup with one cup of water
  • STEP 3: Add the number of tablespoons of sugar to the cups. 0 gets 0 sugar, 2 gets 2 tablespoons of suger, 4 gets 4 tablespoons of sugar, etc... Stir until the sugar is dissolved. This could take a while for the cups with more sugar!
  • STEP 4: Dye each of the cups a color of the rainbow. 0 = red. 2 = orange. 4 = yellow. 6 = green. 8 = blue. 10 = Violet
Cups of varying colors and sugar (Copyright 2024 by KSAT - All rights reserved.)
  • STEP 5: Take the empty cup and add a little of the violet sugar water to to bottom.
  • STEP 6: Using the syringe, slowly add some of the blue sugar water to the cup. It’s best to use the edge of the cup to slowly layer the sugar water.
  • STEP 7: Repeat slowly until you end with the red water with no sugar in it. Hold your cup up to the light and you should see the rainbow layers of sugar water. Cool!
Finished rainbow sugar density tower (Copyright 2024 by KSAT - All rights reserved.)

HOW IT WORKS

As you add sugar to the water, you increase the density. In our experiment, the purple cup is the most dense. The red water is the least dense, so it floats.

SCIENCE WITH SARAH

If you’d like Sarah and David to come to your school and conduct a science experiment live on KSAT, fill out this form. “Winners” are selected at random.

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About the Authors
Sarah Spivey headshot

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.

Robert Samarron headshot
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