Oobleck Video & Lesson Plan
- Large mixing bowl
- 7/8 cup water
- Green food coloring (optional)
- Shallow pan
- Paper towels
- 1 box cornstarch
- Mix the box of cornstarch with 7/8 cup water (ratio = ½ cup of cornstarch to 1/8 cup of water). Add 4-5 drops of green food coloring if desired. Mix well. It is easiest to mix with your hands. The mixture should be the consistency of honey. Add additional water or cornstarch as needed. The mixture should feel hard or stiff when the surface is punched, poked, or slapped. Safety precautions: This mixture is nontoxic but the food coloring may stain clothes or other porous materials.
- Pour the mixture into the aluminum pan. Notice its unusual consistency when you pour it into the pan. Stir it around with your finger, first slowly and then as fast as you can.
- Skim your finger across the top of the glop. What do you notice?
- Sink your entire hand into the glop and try to grab the fluid and pull it up. Note: This works best if using at least two cups of the mixture per container.
- Try to roll the fluid between your palms to make a ball. Stop rolling, and observe the solution.
- Hold your hand flat over the top of the pan and slap the liquid glop as hard as you can.
- Why does the liquid behaves in this manner? What causes it to feel like something solid when you squeeze it, yet flow like syrup as it drips off your finger?