You will need:
- 1 soda bottle
- Water
- 1 funnel
- 1 balloon
- Blu Tack
- 1 straw with a bend in it
- 1 tray to catch excess water
- Optional blue food colouring
- A boxcutter (with adult help)
With adult help, carefully make a small hole in the side of the plastic bottle with the boxcutter.
It can be worth cutting away some of the plastic completely rather than making an ‘X’ shape, this will allow the straw to sit easily in the hole.
Seal around the straw with Blu Tack or modelling clay. make sure that the bottle is dry here or the Blu Tack won’t stick as well. Keep the star pointed upwards.
Optional: add some food colouring to your water
Add the funnel to your bottle and carefully pour your water into the bottle.
You’ll notice that water will rise up through the straw to the same height as the water inside the bottle. This is due to equal air pressure pushing downwards through the opening of the straw and the bottle.
Blow up a balloon and pinch the opening tightly. Carefully stretch the opening of the balloon over the mouth of the bottle without letting go of the neck of the balloon.
Quickly release the balloon and watch the fountain stream out!
The water will continue to stream outwards as long as both the end of the straw is in the water inside the bottle and that the balloon continues to push air into the bottle.
Get the Unit of Work on Pressure here!
- Want to dive into air pressure?
- It’s all about air pressure in many ways!
From how storms form to how planes fly, this unit covers many concepts about air pressure.
Includes cross-curricular teaching ideas, student quizzes, a sample marking rubric, scope & sequences & more
School science visits since 2004!
– Curriculum-linked & award-winning incursions.
– Over 40 primary & high school programs to choose from.
– Designed by experienced educators.
– Over 2 million students reached.
– Face to face incursions & online programs available.
– Early learning centre visits too!
Online courses for teachers & parents
– Help students learn how science really works
Why Does This Happen?
It’s all about air pressure! When the bottle was open, the air pressure pushing down the neck of the bottle and the straw opening was the same. This is why water was able to be at the same height inside the straw as well as the bottle, even when you filled past the opening. By adding an inflated balloon and releasing it, you created a pressure difference between the neck of the bottle and the straw opening. As there was a higher air pressure within the bottle than within the straw, the water got pushed out as stream.
Variables to test
- What happens when you turn the straw upside down? Try this when the water level is above the straw opening height.
- Would the stream of water be a different length with a larger or smaller balloon?
- What would happen if this was done on a mountain top vs sea level?
- Try adding a curly shaped straw to your experiment.
- What would happen if you have two or three straws attached?
- Teaching about air pressure? Check out the Flight or Weather show!
- Teaching about Newton’s laws? Check out the Forces, Friction & Movement workshop!
Get in touch with FizzicsEd to find out how we can work with your class.
Learn more about air pressure!
Get the 60-minute video + PDFs + curriculum links for your class here!
Working with Water
Years K to 2
Maximum 30 students
School workshop (NSW & VIC)
60 or 90 minutes
Online Class Available
STEM Full Day Accelerator - Primary
Designed from real classroom experiences, this modular day helps you create consistently effective science learning that directly address the new curriculum with easily accessible and cost-effective materials.
Budding Scientist Party
Designed for younger kids
Hands on science experiments
Slime making
Professional science show
From $395 inc. GST
answer of this ques ?
Try adding a curly shaped straw to your experiment.
Nice!