Science Smarts: It’s always more fun when it gets a little messy!

By Patty Rooks on April 26, 2025.

I do not know about you, but I love making a mess when I am experimenting! This week, we are going to get messy so prepare yourself as it is all in the name of learning. Let’s get started!

Materials

– Cornstarch

– Vegetable oil

– Mixing bowl

– Spoon

– Balloon

– Measuring cups

– Science helper

Procedure

1. Measure and pour 60 mL (1/4 cup) of cornstarch into a mixing bowl.

2. Add the same amount of vegetable oil into the mixing bowl.

3. Gently stir the mixture until it thickens.

4. Blow up a balloon and tie it off.

5. Charge the balloon – the easiest way is to ask your science helper if you can rub it vigorously in their hair!

6. Take the spoon and get a heaping amount of the mixture on it.

7. Hold this over the bowl and gently allow it to flow off.

8. Have your science helper place the charged balloon close to the spoonful of the cornstarch mixture as you are slowly pouring it off.

9. Observe what happens!

What is going on?

You should of observed the mixture moving towards the balloon. This is because when you rubbed the balloon on a coarse surface like your hair, you give the balloon additional electrons. These new electrons generate a negative static charge. Meanwhile the cornstarch, having identity issues about being a solid or a liquid (it is a non-newtonian fluid) and has a neutral charge.

When an object has a negative charge, it will repel the electrons of other objects and attract that object’s protons. When the neutrally charged object is light enough, like the dripping cornstarch in this case, the negatively charged object will attract the lightweight object. But try attracting cornstarch while it’s in the bowl… it doesn’t work!

You need to reduce the amount of other forces acting on the cornstarch for this experiment to work, and that’s why you drip it from the large spoon. Dripping the cornstarch means fewer cornstarch molecules will be able to stick to each other, which enables the dripping cornstarch to swing towards the balloon more freely.

Patty Rooks, senior scientific consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: 12 826 11th Street SE, Medicine Hat, AB, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.

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