Choose the sheet for the learner's age. Each prints on a single page. Build the project first, then fill it in together.
Ages 5-7: Draw & tell
Name: ______________________Date: ____________
Homemade Science with Bruce Yeany · Upside-Down Water Glass · Ages 5-7
The Magic Water Cup
Flip the cup and look closely at what the water does.
1. Guess first. When I let go of the card, the water will...
◯ Pour out◯ Stay in
2. Draw your cup upside down with the card. Draw an arrow showing the air pushing on the card.
3. I tipped the cup and air got in. The water...
◯ Stayed in◯ Fell out
4. Which one fell out right away?
◯ Sand◯ Water
5. The best cover was:
Ages 8-10: Predict, test & record
Name: ______________________Date: ____________
Homemade Science with Bruce Yeany · Upside-Down Water Glass · Ages 8-10
Best Cover Contest
Predict which cover holds the water best, then test them over the tub.
1. Predict first: which cover will hold the water best?
◯ Stiff plastic◯ Cardboard◯ Foam plate◯ Balloon
2. Test each cover on the same cup, filled to the brim. Count the seconds it holds (stop at 30).
Cover
Did it hold? (yes/no)
Seconds it held
Any drips?
3. What did you find out? Which cover worked best, and which worked worst?
4. What happened when you tipped the cup and a bubble of air got in?
◯ The water stayed in◯ The water fell out
5. Why do you think dry sand falls out, but water stays in?
Ages 11-14: Explain & design your own test
Name: ______________________Date: ____________
Homemade Science with Bruce Yeany · Upside-Down Water Glass · Ages 11-14
Upside-Down Water: Pressure Investigation
Explain the trick with air pressure and cohesion, then design your own fair test.
1. Use the words air pressure and cohesion to explain why the water stays in the upside-down cup.
2. Bruce's pressure gauge showed that the pressure at the top of the trapped water (the bottom of the upside-down cup) is...
◯ Higher than the air outside◯ The same as the air outside◯ Lower than the air outside
3. Two upside-down tubes are the same height. One is narrow and one is wide. Which has the bigger pressure drop at the top?
◯ The wide one (more water)◯ The narrow one (less water)◯ About the same
4. For a 'best cover' test, name the variables.
What I change
What I measure
What I keep the same
5. Design your own fair test (for example: how far you can tilt, how full the cup is, or cup size).
My question
What I will change
What I will keep the same
What happened
6. Where else can a liquid be held in by blocking the air? (Hint: try the straw challenge.)
Answer guide for grown-ups
Homemade Science with Bruce Yeany · Upside-Down Water Glass · Answer guide
Answer guide
Ages 5-7: The Magic Water Cup
Stay in (maybe a drip or two).
Look for an arrow pointing up at the card from below.
Fell out.
Sand.
Open answer: look for effort and careful observation.
Ages 8-10: Best Cover Contest
Open answer: look for effort and careful observation.
Open answer: look for effort and careful observation.
Any answer that matches their data. Bruce found balloons and flexible lids sealed best, stiff plastic slipped off easily, and cardboard worked until it got soggy.
The water fell out.
Water sticks to itself, so it stays together like one plug and air can't get in. Sand grains don't stick together, so air slips between them and the sand falls.
Water's cohesion keeps it together as one plug, and the card blocks air from getting in. Air pressure pushes on the card from outside; with no air inside to push back, the water can't fall unless air takes its place.
Lower than the air outside.
About the same: the pressure drop depends on the height of the water, not the amount.
Change: the type of cover. Measure: whether it holds and for how long (or how much leaks). Keep the same: the cup, how full it is, the water, how you flip it.
Open answer: look for effort and careful observation.
A straw with your finger over the top; also an eyedropper or pipette, or a pet water bottle or bird waterer that only empties as air bubbles in.