Super Cold Bag

The Super Cold Bag

Watch a zip lock bag blow up and become super-cold from a chemical reaction. Youíll love this one!

Suitable for kids aged 4+
You Need:
  • Citric Acid
  • Baking Soda
  • Tap Water
  • Zip lock bag (15cm x 10cm)
  • Measuring cup
  • Plastic spoons
  • Teaspoon

Perform this experiment over a kitchen sink. There is a small chance the zip lock bag will burst making a wet mess! Zip lock bags of different sizes can be used, but the quantity of chemicals added will vary. Trial and error will uncover the correct amount to use to blow the bag up fully.
What to do:
  1. Put one level teaspoon of citric acid in a zip lock bag.
  2. Put one teaspoon of baking soda in the same zip lock bag. And shake the bag gently to mix the two chemicals.
  3. Fill up the measuring cup with cold tap water (about 30ml).
  4. Here's where you have to be quick! Pour the water into the zip lock bag and snap it shut fast.
    Not only does the bag blow up, it also becomes super cold! So donít forget to feel its temperature.
  5. You can try putting about 20ml of vinegar and a flat teaspoon of baking soda into a zip lock bag and snapping it shut quickly. Compare the difference between this and the other combination of chemicals.

Why is it so?

Mixing citric acid, baking soda and water together causes a chemical reaction. The new chemical that is made is carbon dioxide gas. This gas fills the bag and causes it to blow up. Youíll also notice the bag drops in temperature as part of the chemical reaction.

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