activity

How do you make a pie filling that holds its shape when you slice it? Learn the science-y secret to perfect pie slices in this edible experiment.

safety
  • Uses the microwave
difficulty
  • Beginner
time
  • 45 minutes
yield
  • Makes about ½ cup mashed blueberries

hey curious cook—

Have you heard about our Young Chefs’ Club? Members get a themed (and kid-tested) box delivered each month!

Prepare Ingredients

¾ cup (3¾ ounces)
blueberries
1 teaspoon
sugar
1 teaspoon
cornstarch

Gather Equipment

Masking tape
Marker
Large plate or serving platter
3
small microwave-safe bowls
¼-­cup dry measuring cup
Potato masher or fork
3
spoons
Oven mitts
1-­tablespoon measuring spoon
Ruler
1
 

Make 3 masking tape labels. Use marker to write “Control” on 1 label, “Sugar” on second label, and “Cornstarch” on third label. Place labels side by side across top of large plate, leaving 1 inch between each label. (In an experiment, the control is the sample in which you don’t add or change anything.)

 
2
 

Use 3 more pieces of masking tape and marker to create second set of “Control,” “Sugar,” and “Cornstarch” labels. Place 1 label on each microwave-safe bowl.

 
3
 
¾ cup (3¾ ounces)
blueberries

Use ¼-cup dry measuring cup to scoop ¼ cup blueberries into each labeled bowl. Use potato masher or fork to mash blueberries until they are mostly broken down.

 
4
 
1 teaspoon
sugar
1 teaspoon
cornstarch

Add sugar to bowl labeled “Sugar” and use spoon to stir until well combined. Add cornstarch to bowl labeled “Cornstarch” and use clean spoon to stir until well combined.

 
5
 

Make a prediction: Do you think the 3 bowls of blueberries will look the same or different after you cook them in the microwave and let them cool? Why do you think so?

 
6
 

Place bowl labeled “Control” in microwave and heat until blueberry mixture bubbles, about 1 minute. Use oven mitts to remove bowl from microwave (ask an adult for help). Use clean spoon to stir blueberries. Repeat heating and stirring with bowls labeled “Sugar” and “Cornstarch.” Let all 3 bowls of blueberries cool completely, about 20 minutes.

 
7
 

Observe your results: Place 1 tablespoon of “Control” blueberries below “Control” label on plate. Repeat with “Sugar” blueberries and “Cornstarch” blueberries, making sure to clean measuring spoon between scoops. Hold edge of plate closest to blueberries and lift edge of plate up about 6 inches, leaving bottom edge of plate on table. Hold plate at angle for 5 seconds. Return plate to table. What did you notice? How far did each blueberry mixture travel down the plate?

 
8
 

Eat your experiment: Combine all blueberries in 1 small bowl. Use spoon to stir until combined. Spoon blueberries over yogurt, oatmeal, ice cream, pancakes, pound cake, or your favorite dessert.