cart Shopping Cart cart(0)

Upside down water cup experiment

You will need:

 
  • 1 styrofoam cup of water, full to the brim
  • 1 piece of card, larger than the cup rim (you could use paper too!)
  • An area where you can get wet!

    Copyright notice

Instructions

 
  1. Make sure your cup is completely full, i.e. about to spill over the side.
     
  2. Gently place a dry card on top of the cup... making sure there is good contact over the cup rim.
     
  3. Carefully turn the cup upside down, keeping upward pressure on the card

    Air pressure demonstration
     
  4. Can you explain why the water doesn't come out?
 
Be Amazing Book Front Cover; Ben Newsome, teacher & founder of Fizzics Education. Be Amazing -how to teach science the way primary kids love
Be Amazing!
How to teach science, the way primary kids love

 
Read more about Be Amazing

Why does this work?


Air molecules are constantly pushing into things, in every direction imaginable. In other words, air has pressure. If you look at your thumbnail, you have the equivalent of around 1 kg of weight pushing down on that body part alone!

Inside the cup there was no air, so the weight inside the cup was coming only from the water. Depending on the size of your cup, the weight of the water may have been around 250g. The air below the card was pushing up into the card. The upwards air pressure was much greater than that of the pressure of water pushing towards the ground - keeping the water in the cup.

Air locks are used by deep sea divers leave their submersible vehicles. The air inside the air lock is compressed at the same pressure as that of the water outside the air lock.

The equal pressure stops the water from entering the air lock.
NASA even uses airlocks during their underwater training!
 
Other air pressure based science experiments
 
Join our newsletter for more science teaching thoughts & ideas

Join the Fizzics newsletter

Back to force & movement experiments
  • Model a tornado!
  • Kids love this device :)

    science kits for sale
bell jar science experiment

Weather & Pressure school show

 
  • Learn more about convection & weather systems
  • Years 3 to 6
read morebook now

 

>100 Free Science Experiments on this site!

Coloured shadows
  • Experiments to colour your class!
  • Easy & fun
read more
 
skeleton and student
  • Make fake blood & more!
  • Biology made simple
read more
 
electricity experiments
  • Circuit science for kids
  • Cheap materials found easily
read more
 
Sugar and skittles dissolving in water experiment
  • Creative chemical concoctions!
  • Safe and engaging for kids
read more

School Science Visits: 

  • Highly engaging & curriculum-linked
  • Additional Teacher Support Resources
  • Professional visits in-class or via video conference
  • Both Primary School & High School science incursions
Call 1300 856 828 or use this form to discuss or make a show booking for your school!

Email updates

Signup to our monthly email Learn more
 

Contact us

1300 856 828
info@fizzicseducation.com.au

Unit 10/55 Fourth Ave
Blacktown, NSW 2148, Australia
 
facebook-icongoogle-icontwitter-icon
linkedin-icon youtube-icon   pinterest-icon