Food Coloring Race

Hosted by: UT Austin Physics Circus

Recommended Grades: 1st, 2nd, 3rd

The Challenge: Heat up some water in a glass with the help of an adult. Pour some cold water into another glass. In one hand, take the red food coloring and hold it over the hot water glass. In the other hand, take the blue food coloring and hold it over the cold water glass. Now, count down from 3 and drop a few drops of the food coloring into each glass and watch what happens to the dye as it spreads out into the water. See which food coloring can spread out the most in the water and win the race.

Recommended Materials:

  • clear glass of cold water
  • clear glass of hot water
  • red food coloring
  • blue food coloring

How does this activity connect to STEM? Here on Earth we see all of the different states of matter -- think about steam in the bathroom after a hot bath (gas), rain forming puddles on the ground (liquid), and ice cubes floating in your lemonade on a hot summer day (solid). Virtually everything on Earth is made up of the same stuff, or atoms, that exist in these three phases of matter.

The states of matter are connected by temperature. Colder things have their atoms more closely packed together, like solids, and warmer things are more spread out, like gases. They also move around faster too. You can see this happening in the food dye as it spreads in different temperature water.

Activity Video

Follow along with us as we "race" our different food colorings in hot and cold water.

About the UT Austin Physics Circus

In normal times, we are a traveling physics show that brings exciting and educational science demonstrations to the classroom. In covid times, we host a live broadcast of our demonstrations that you can follow along with at home. Our mission is to make science a fun and interactive experience for all, regardless of economic background, race, or gender. This is why we offer the show at no cost to the school. Our program is proudly driven by the enthusiasm of physics graduate students at UT who are passionate about science outreach to the Austin community.

Please visit our website if you'd like to read more about the Physics Circus, view our promotional video, or inquire about shows.