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Supersize Marshmallows

Supersize Marshmallows

Pumping the air out of the bottle changes the pressure inside the bottle. A plastic bottle would collapse in on itself but the solid glass bottle is strong enough to keep its shape. Marshmallows are full of tiny air bubbles and when the air is pumped out of the bottle, the bubbles are at a much higher pressure than the surrounding air. The air in the bubbles pushes outwards, the air molecules move further apart, the bubble gets bigger. We see the marshmallow stretching and growing larger.

What you will need: 

  • Clear glass wine bottle
  • Wine saver pump and vacuum stopper
  • Marshmallows


    1. Wash the bottle and remove any labels.
    2. An adult should demonstrate this experiment for the children to observe, taking care when using the glass bottle.
    3. Push 5 marshmallows into the bottle.
    4. Use the wine saver pump to create a vacuum in the bottle.
    5. Observe the effects of removing air on the marshmallows. They will grow in size.
    6. Remove the stopper and watch the marshmallows shrink back

Some Question Prompts:

Leading questions can lead to some super-discoveries!
After following the Steps above try asking:
    1. What is in the bottle? (Marshmallows)
    2. Is there anything else in the bottle? (Air)
    3. What is being pumped out of the bottle?
    4. What is happening to the marshmallows?
    5. What happens when we let the air back into the bottle?
Supersize Marshmallows