Water & Food Coloring Experiments

Many scientific phenomena are demonstrated to children through experiments using common, everyday ingredients. Teaching science to kids through safe experimentation helps children increase their interest in the subject, as well as the likelihood they will retain the information being taught. Two simple ingredients that can be used to execute a broad range of visually exciting experiments are water and food coloring.

Allow kids to literally watch how a plant takes in water with a piece of celery placed in a cup of colored water. For one cup of water, 10 drops of red or blue food coloring are added. Over the course of the following two days, the colored water will visibly creep up through the capillaries of the celery. This process is called transpiration, and it provides an opportunity to talk to kids about how plants take in water from the soil and how the capillaries help distribute the water throughout the plant. Chopping the stalk into thin slices will further demonstrate the paths of the capillaries.

Adding food coloring to this familiar experiment, makes the repellent movement of oil against water visual. After filling a tall glass with cold water, it is topped with about an inch of colored cooking oil. When stirring, children will see the streams and globs of colored oil as they disperse through the water without dissolving. Once stirring has stopped, all the colored oil particles will rise back to the top of the glass. This provides an opportunity to talk to children about the molecular differences between oil and water that prevent them from integrating when stirred.

Adding a few drops of food coloring to a bowl of water, then stirring, will immediately help children visualize the way water moves when it is circulating. A glass bowl is the best container to use, so everyone can see the full effect. The water is stirred rapidly in a spinning motion to get it moving. After the food coloring is added to the center, kids can watch the thin, spiraling strings of food coloring enter the water. This is an opportunity to talk to them about Brownian motion, which deals with the movement of particles suspended in liquid or gas. The food coloring will appear to move slower and will tend to sink once the motion subsides. The density difference between water and food coloring that causes this sinking provides further opportunity for discussion.