Calculating Dietary Energy · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.
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Calculating dietary energy

Science · Organisms & Life Processes · ages 11-13
Name ______________________   Date ____________

  1. Kilocalories (kcal) and kilojoules (kJ) are two different units for measuring the same thing: energy in food.

    Circle one:   True   False

  2. A juice bottle label shows 'Energy: 420 kJ / 100 kcal'. Which number is measured in kilojoules?

    • 420
    • 100
    • Both numbers show kilojoules

  3. For the same person, with other conditions unchanged, which afternoon is likely to require more energy?

    • An afternoon spent reading quietly
    • An afternoon spent training for football
    • Both afternoons must require exactly the same energy

  4. A classroom table gives Jess, age 12, these estimates: less-active day, 1900 kcal; training day, 2300 kcal. Which entry matches her training day? These exercise figures are not personal eating targets.

    • 2300 kcal
    • 1900 kcal
    • 4200 kcal

  5. A cereal bar label shows 800 kJ per bar. For this rough estimate, use 4 kJ for every 1 kcal. About how many kcal is that?

    Answer: ______________

  6. The chart gives kcal per serving: Lunch A 450, Lunch B 700, Lunch C 550. Compare two servings of A with one serving each of B and C. Which portion supplies the most energy?

    Lunch A450Lunch B700Lunch C550
    • Lunch B
    • Lunch A
    • Lunch C

  7. In a classroom model, meals contain 350, 600 and 700 kcal, and a snack contains 150 kcal. The supplied daily guide is 2000 kcal. How many kcal below the guide is the total?

    Answer: ______________

  8. In a classroom model, Priya's meals and snacks total 2600 kcal and the supplied guide is 2000 kcal. How is the total classified relative to this guide?

    • Equal: a model match
    • Below: model deficit
    • Above: model surplus
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Calculating dietary energy W1-mt_83KkBCtVyR-s1

  1. True · Both units measure energy. Their numbers differ because the units have different sizes.
  2. 420 · kJ means kilojoules. The number beside kJ is 420.
  3. An afternoon spent training for football · Football training is more active than quiet reading, so it usually requires more energy for the same person.
  4. 2300 kcal · Match the kind of day to its entry. The supplied training-day estimate is 2300 kcal.
  5. 200 · Using the stated rough factor, 800 ÷ 4 = 200 kcal.
  6. Lunch A · Two servings of A supply 2 × 450 = 900 kcal. This exceeds B's 700 kcal and C's 550 kcal.
  7. 200 · 350 + 600 + 700 + 150 = 1800 kcal. The gap is 2000 - 1800 = 200 kcal below the guide.
  8. Above: model surplus · 2600 kcal is 600 kcal above the supplied guide, so it is a model surplus. This does not measure Priya's actual energy use.
Worksheet · LightMySky