Fizzy Pumpkin Cups

Our fizzy pumpkin cups are a simple fizzy science activity for Halloween. We drew a pumpkin face on a plastic cup and set up a baking soda and vinegar reaction in the cup. The orange foam fizzes up to show the pumpkin face.

If you can keep the fizz inside the cup, this is an almost mess free science activity that looks amazing!

We used washing-up liquid/dish soap in one of the cups to see the difference it makes to the fizz. You can see the left cup is more foamy than the right.

Fizzy Pumpkin Cups

You'll need

Orange food colouring

Baking Soda

Plastic cups

Black marker pen

Vinegar

Water

Dish soap/washing up liquid

Instructions

Draw a pumpkin face in the middle of each cup using a black marker pen.

Place a teaspoon of baking soda, a teaspoon of washing-up liquid/dish soap, and a little food colouring into each cup, along with water. The exact amounts aren't important, in fact, it's fun to experiment with different amounts of each to observe how the fizz changes.

Add about 20ml of vinegar and watch as the cup fills with orange foam!

Why does the mixture fizz?

Baking soda and vinegar react to neutralise each other ( vinegar is an acid and baking soda is an alkali ), releasing carbon dioxide, which makes the mixture fizz upwards!

The washing-up liquid/dish soap makes the fizz thicker and more foam like.