15-minute experiment

Thickening with cold vs hot starch

Q: What does the thickening with cold vs hot starch experiment test?

It tests one variable: how the starch goes in. The idea is that cornstarch mixed with cold water thickens smoothly, and cornstarch sprinkled straight into hot liquid clumps.

Lumps are a choice.

The idea

Cornstarch mixed with cold water thickens smoothly, and cornstarch sprinkled straight into hot liquid clumps.

The one thing you change: How the starch goes in

You need

2 tsp cornstarch
2 small pots with 1 cup of hot water each
A spoon
A little cold water

Steps

Stir one teaspoon of cornstarch into 2 tbsp cold water until smooth.
Pour that slurry into pot one while stirring. Sprinkle the other teaspoon of dry cornstarch straight into pot two.
Simmer both for one minute, stirring, and compare. Let them cool before tasting, because thick starch holds heat.

What you should find

The slurry thickens smoothly. The dry starch forms lumps that are slow to disperse.

From the app

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