9 Activity: Water Fireworks

Supplies per student

1 clear plastic cup

1/4 cup baby oil

Food coloring – A variety of colors

1 cup water

Question: What do you think will happen when we add oil to water? What do you think will happen when we add drops of food coloring?

Directions: Add 1 cup water to plastic cup. Add 1/4 cup baby oil and observe what happens. The oil should settle on top in a layer. Add several drops of different colors of food color and don’t disturb the experiment. Over time the drops will settle at the bottom of the oil layer and then mix with the water creating an “explosion” effect.

Theory: Water is hydrophilic (water-loving) and oil is hydrophobic (water-fearing), so they don’t mix. Maybe you’ve observed this with salad dressing. Food coloring is water-based, so it will form beads in the oil layer, then diffuse when it reaches the water.

Grades: 1st – 4th

Time: 15 minutes

Clean-Up: Have the students empty their cups in a sink or tub. Contents can go doing the drain. Wash the cups for reuse.

Notes and Hints: Advise the students to keep their fingers out of the cups and not bump the table. Observe with eyes. To catch messes, you may want to put the cups on plastic plates.

Image Credit: https://www.youtube.com/watch?v=tLYBV_19LoI