PSYCH 018 Index > Band Around the Earth

Band Around the Earth

This is adapted from The Education of T.C. Mits, by Lillian Lieber

circle with red circle tightly around it Presume that you have a steel band that fits tightly around a perfectly spherical earth at the equator. That band will be about 25,000 miles long.

two nested circles Now cut open the band and add 10 feet to its length, and weld it back together again. (That’s 10 feet, not miles.) That leaves some room between the earth and the band. If you center the earth in this slightly larger band, how much room will there be between the band and the earth?

  1. Enough for an average person (5 feet 9 inches) to walk under the band.
  2. Enough for a cat to walk under the band.
  3. Enough to slip a piece of paper under the band.
  4. Not even enough to slip a piece of paper under the band.

What does your common sense tell you the answer is? What did you guess? Are those the same?

See the correct answer