The Shrinking Soda Can
FrizzCo, a soda company, gave its drink a new can — same $1.50. But is there as much soda inside?
Concept
Same price, smaller product. Companies quietly shrink the size of everyday items while keeping the price the same, hoping no one notices. Kid uses real volume formulas to catch them in the act.
The Experience
In round one, a soda company's "sleek new" can looks about the same size as the old one, but calculating volume with πr²h for both shows the new can actually holds 15% less — same price.
In round two, an old and new chocolate bar look identical from the wrapper, but calculating volume with length × width × height reveals the new bar has deeper grooves between its squares and lost two whole squares' worth of chocolate.
In round three, a tissue roll looks unchanged on the outside — same height, same outer diameter — but the cardboard tube inside got wider, so a hollow-cylinder calculation (πh(R²−r²)) shows there's less actual tissue wrapped around it.
In every round, the kid builds the volume formula from the shape itself rather than being handed it, then uses price-per-unit-volume to work out which version is really the better deal.
What Math Does The Kid Do?
- Measures dimensions: radius, height, length, width.
- Calculates the volume of cylinders (πr²h), rectangular prisms (l×w×h), and hollow cylinders (πh(R²−r²)).
- Compares old and new volumes and calculates percentage decrease.
- Builds a volume formula from a shape rather than being given one.
- Calculates price-per-unit-volume to find the real cost.
Why This Matters
Hand you any two product sizes and you can do the math to tell which is really the better deal — and catch a company that quietly shrank it.
Frequently asked questions
The Shrinking Soda Can is tagged for Grades 6-12.
No — The Shrinking Soda Can plays directly in the browser, right on this page. No login, no download.
Fact-check a real-world claim — is it true, or does it just look true?
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