This activity is designed to experiment with mixing two items with different properties, a liquid and a solid. (Your child may have already encountered this mixture in preschool, possibly under the name oobleck.)

Using observation and exploration skills, you and your child can compare and discuss what happens. If you haven’t played with goop before, you may find that The goop has properties of both solids and liquids. As you and your child make and play with the goop, use comparison words such as thin, thick, wet, dry, liquid, solid and changing.

What You’ll Need

  • 1 ½ cups cornstarch
  • 1 cup water Measuring cups
  • Spoons
  • Pan(s) or large bowl(s)
  • Airtight container

Here’s how to do it

Set up the ingredients and the bowls or pans. Have your child help you make the mixture. Measure the cornstarch and water in a container. Mix with a spoon. Add more water if the mixture seems too dry. If the mixture seems too wet, add cornstarch.

Observe what happens. As you work, use words such as measure, equal, powder, liquid, dry, wet and mixture to describe the process. Play with the goop. Touch and smell the goop, but do not taste it. Ask your child questions such as:

  • How does it feel? (before and after the mixing)
  • What happens when you stir it together?
  • How long can you keep the goop in your hand before it slips away?
  • Can you squeeze it into a ball?
  • What else do you notice?

Experimenting along with your child will allow you both to make discoveries and communicate what you are learning. When you’re finished, place the goop in an airtight container and store it in the refrigerator for later use. Goop turns to back to cornstarch powder when it is dry which makes this activity extremely easy to clean up. (When you are ready to discard the goop, be sure to put it in the trash. Do not pour it down the drain because it could clog it.)

Younger children will tend to mix several colors – mixing being the more interesting activity. Older children will tend to have more patience and interest in the process described here. Help your child to answer her own questions by encouraging experimentation, making predictions and then telling you what she has learned.

Activity extenders

  • Read the Caldecott Honor book related to this activity, Bartholomew and the Oobleck, by Dr. Seuss.
  • Add food coloring to the goop or place small plastic animals in the goop to experiment with the textures and properties of this mixture.