Printable worksheet · Ages 11 to 16 · about 20 minutes

How much would you weigh on the Moon, Mars and the ISS?

A one-page worksheet: weight = mass × g on the Moon and Mars, and gravity at the space station's live height, with why astronauts float.

Numbers

Today's numbers come from the Live ISS tracker, captured when this page loaded: 12:19 UTC on 4 November 2026. Print the class set in one go so every copy matches the teacher notes. Reload for new numbers.The boxes are left blank. Pupils open the Live ISS tracker and copy in the numbers themselves, so answers vary a little: the teacher notes give the method and the range to accept.Live numbers are not available right now, so the boxes are blank: pupils look them up in the Live ISS tracker.

Orbital Radar · Space for Schools
Ages 11 to 16 · Weight and gravity

How much would you weigh on the Moon, Mars and the ISS?

Your mass is how much matter you are made of, in kilograms. Your weight is the pull of gravity on you, in newtons. Weight = mass × g, where g is the gravitational field strength: how many newtons each kilogram is pulled with.

Name Class Date
Today's numbers from the Live ISS tracker, 12:19 UTC on 4 November 2026write the height in from orbitalradar.com/iss-tracker
Height of the ISS above the ground
426 km
g at that height
8.6about 8.6 N/kg
g on the Earth's surface
9.8 N/kg
g on the Moon
1.6 N/kg
g on Mars
3.7 N/kg

Open orbitalradar.com/iss-tracker and copy the height of the ISS.

  1. A pupil has a mass of 40 kg. What is the pupil's weight on the Earth? Use: weight = mass × g.[2]

    N

  2. What would the same pupil weigh on the Moon? And on Mars?[2]

    N on the Moon
    N on Mars

  3. What is the pupil's mass on the Moon? Explain your answer.[2]

  4. Use g at the ISS's height today to work out the pupil's weight up there.[2]

    N

  5. Challenge. Gravity at the ISS is almost as strong as on the ground. So why do astronauts float?[2]

Extension  g gets weaker further from the centre of the Earth: g = 9.8 × (6,371 ÷ r)2, where r is the distance from the centre in km. Use today's height to check the value of g at the ISS. [3]

Check: on the Moon you weigh about one sixth of your weight on the Earth.

orbitalradar.com/schools/uk/worksheets/weight-other-worldsNumbers captured 12:19 UTC, 4 Nov 2026Free to copy for teaching
Teacher notes and answersNot on the pupil sheet. Printed only with "Print with answers".

Teacher notes: How much would you weigh on the Moon, Mars and the ISS?

Worked from the height on today's sheet: 426 km, so g there is 8.6 N/kg (12:19 UTC on 4 November 2026).

Pupils used the fixed value, about 8.6 N/kg: g at the ISS is 8.6 or 8.7 N/kg for any height from 400 to 430 km.

Total 10 points, plus 3 for the extension.

Answers

  1. 40 × 9.8 = 392 N (1 for the method, 1 for the answer)
  2. Moon: 40 × 1.6 = 64 N. Mars: 40 × 3.7 = 148 N.
  3. Still 40 kg. Mass is the amount of matter, and it does not change from place to place. Weight changes because gravity on the Moon is weaker.
  4. 40 × 8.6 = 344 N.40 × 8.6 = 344 N. Accept 344 to 348 N.
  5. The ISS and everyone in it are falling towards the Earth all the time. They also move sideways so fast, about 7.7 km every second, that they keep missing it: they are in free fall together, so nothing pushes up on the astronauts and they float.

Extension: r = 6,371 + the height = 6,371 + 426 = 6,797 km; (6,371 ÷ 6,797)2 = 0.879, and 9.8 × 0.879 = 8.6 N/kg. (1 for r, 1 for squaring, 1 for g)

Watch for

  • Weight given in kilograms: weight is a force, measured in newtons (N).
  • "There is no gravity in space": at the ISS's height it is still nearly 90% as strong as on the ground.

Curriculum

England: KS3 Space physics (weight = mass × gravitational field strength, different on other planets). Scotland: SCN 3-08a. Wales: Curriculum for Wales, Science and Technology, Forces and energy (progression step 3). Northern Ireland: KS3 Science, Forces and energy; CCEA GCSE Physics 1.2.9 and Single Award 3.9.5. WJEC Integrated Science 2.2.1a and The Sciences 3.3.1 (why astronauts float).

How these worksheets work

One page, free to print and copy for teaching. The numbers on the sheet are captured from the live tool when the page loads, and printed with the time, so a class set printed together matches the teacher notes. Reload for new numbers.

No sign-in, no ads, and nothing for pupils to install.

Where this fits

All United Kingdom activities