🥫 Primary Maths & Science Games · Grade 6 · Cylinders and cones
Cylinder and Cone: Unroll, Slice, Pour
The three classic slips: using the diameter as the radius, counting one base too many or too few, and forgetting the ⅓ for a cone. First see where the formulas come from by unrolling, slicing and pouring, then practise.
- Free, no sign-up
- Ad-free play area
- Tablet friendly
- Parent mode
- A4 worksheet
- 5 levels
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How to play
- In Explore, drag the base radius and height. In “Unroll the side”, drag how far it unrolls and watch the side become a rectangle.
- In “Slice into a block”, choose 8, 16 or 32 pieces: the more slices, the closer to a block with length πr, width r and height h.
- In “Pour a cone”, tap “Pour once”: a cone with the same base and height fills the cylinder in 3 pours.
- Five levels: curved surface → surface area (with open buckets) → cylinder volume → cone volume → pouring questions, using π = 3.14.
Curriculum unit
Primary maths, grade 6: cylinders and cones, surface area, volume of a cylinder and of a cone (PEP textbook, grade 6 volume 2, unit 3).
For parents and teachers
Mistakes are grouped as forgetting the 2 in 2πr, diameter used as radius, mixing area and volume, number of bases, radius not squared, forgetting the ⅓ and decimal slips. A cone answer equal to the cylinder volume almost always means the ⅓ was forgotten: let your child pour it three times.
FAQ
How do you find the curved surface area of a cylinder?
Cut the side along the height and unroll it: it is a rectangle with length 2πr (the circumference) and width h, so the curved surface is 2πrh.
Why is a cone one third of a cylinder?
Fill a cone with the same base and height with water and pour it into the cylinder: three pours fill it exactly, so cone volume = ⅓ × base area × height. The base and height must be the same.
How much metal does an open bucket need?
Only the curved surface and one base: 2πrh + πr².