Free PDFGrade 3 · Science · 30 min
Whirlpool in a jar
Swirl a jar of water and make your own mini vortex.
I can make a vortex and explain why it slows down and stops.
A science experiment video with a free worksheet and answer key for teachers
About the video
In the video a jar of water is swirled and a spinning funnel forms in the middle. At home your child adds dish soap, vinegar and food colouring to 450 ml water, swirls the jar 5, 10 and 15 times, and times how long the vortex lasts.
Moving water wants to go straight, so the jar wall pushes it into a circle, the water piles up at the sides and a dip forms in the middle. More swirls give more spinning energy, and friction with the jar slowly takes that energy away until the water stops.
What your child learns
- Make a vortex and name real ones like tornadoes
- Time the vortex and compare 5, 10 and 15 swirls
- Explain how friction slows spinning water down
What's on the worksheet
- 1Predict first
- 2Time your vortex
- 3What did you see?
- 4The science behind it
- 5Key words
- 6Vortex maths
- 7True or false
- 8Vortex or not?
- 9Draw and label
You need
1 clear jar with a tight lid (about 500 ml), 450 ml water, 1 teaspoon dish soap, 1 teaspoon vinegar, 2 drops food colouring, 1 stopwatch or timer.
Tip for the adult
Wait until the water is completely still before each new try, otherwise leftover spin makes the times longer.
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