Read the Haunted House Story. Refer students to The Haunted House story in the Student Guide. Explain that this story is about a footprint in a haunted house. Begin the lesson by briefly discussing and comparing feet.
- Do you think your feet are the same as your neighbor's feet?
- How do you think they are different?
- Do you think you could identify someone by their footprint?
- Do you think footprints could be used to solve a mystery?
Use the following discussion prompts as you read The Haunted House story in the Student Guide with the class.
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- Who or what do you think made the footprint?
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- Explain how you would find the area of the footprint. (Peter and Rosita can trace the footprint and use grid paper to estimate its area.)
- What problems might they encounter in measuring length? (They need to decide which part of the footprint to measure to find its length. Measuring from the heel to the tip of the big toe will provide a different answer than measuring from the heel to the tip of the little toe. Similar problems would result if they use width.)
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- Why does Rosita want to count the area independently from Peter? (Both Rosita and Peter should count so that they know their estimate is accurate.)
- Why does Peter say the measurement is about 53 square centimeters? (His answer is an estimate of the area. Peter is estimating the area to the nearest whole number.)
- Is it reasonable to estimate? (Since the estimate of the area of a curved shape is not precise, it is reasonable to estimate.)
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- Why did Peter and Rosita measure both the area and the length of the foot? (Students can now apply what Peter said earlier: Although some classmates have the same length or the same area, very few students will have the same length and the same area.)
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- Which of the students could be the “ghost”? John and Brian are the most likely candidates although neither of these boys' measurements matches Peter and Rosita's data exactly. This is a good place to discuss the possibilities of measurement error.)
- Why are all the measurements written on the board in whole numbers? Do you think that all the students' measurements would have “come out even”? Do you think that students rounded the answers? (Most of the measurements were probably not whole numbers, but were rounded to the nearest whole number.)
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- Why did Peter and Rosita decide to follow John? (The area of the ghost's footprint is within one square centimeter of the area recorded for John's foot, and the length of the ghost's footprint is exactly the same as John's. Also, Rosita noticed that John didn't want to take off his shoes and measure his foot, so she is suspicious of him.)
