Where this unit fits in / Prior learning
This unit builds on:
unit 7K Forces and their effects and unit 7L The Solar System and beyond. The historical impact of discoveries in astronomy is covered in unit 21 Scientific discoveries in the history scheme of work. / To make good progress, pupils starting this unit need to understand:
  • that the gravitational attraction of the Earth on a mass causes weight about the planets of the Solar System, how they orbit the Sun, and how satellites, e.g. moons, orbit them
  • that forces affect the motion of bodies.

The concepts in this unit are:
gravity causes an attractive force between any two objects with mass; gravitational attraction depends on the mass and the objects and their distance apart; gravitational attraction keeps the Solar System together; ideas about the Solar System have changed over time.
This unit leads onto:
further work in key stage 4 on theories about the nature and evolution of the Universe.
This unit relates to:
unit 9K Speeding up.
Framework yearly teaching objectives - Forces
  • Recognise that gravity is a force of attraction between objects, that this force is greater for large objects like the Earth but gets less the further an object moves away from the Earth′s surface; use these ideas to explain:
– how weight is different on different planets;
– how stars, planets, and natural and artificial satellites are kept in position in relation to one another.
  • Be able to give examples of the uses of artificial satellites.

Expectations from the QCA Scheme of Work
At the end of this unit …
… most pupils will … / … some pupils will not have made so much progress and will … / … some pupils will have progressed further and will …
in terms of scientific enquiry NC Programme of Study Sc1 1a, c, 2i, j, m
  • use a model of gravitational attraction to explain orbiting
  • describe how ideas of the nature of the Solar System have changed over time and relate these to available evidence
  • make effective use of secondary sources to find information from recent space exploration about the nature of the Solar System.
/
  • describe some early ideas about the Solar System.
/
  • explain how experimental evidence has led to changes over time in models of the Solar System
  • evaluate recent information and ideas about the origin of the Moon.

in terms of physical processes NC Programme of Study Sc3 1b; Sc4 2b, 4c, e
  • recognise that gravitational attraction is a universal force of attraction between objects and that this force depends on their masses and distance apart
  • describe how weight is different on different planets
  • give examples of the use of artificial satellites.
/
  • recognise that weight is less on the Moon
  • describe gravitational attraction as a force which acts throughout the Solar System
  • give examples of the use of artificial satellites.
/
  • use data to compare gravity on different planets
  • describe how the forces on rockets or satellites vary as they travel away from the Earth.

Suggested lesson allocation (see individual lesson planning guides)
Direct route
J1
A massive problem / J2
Satellites / J3
The Solar System / J4
Birth of the Moon – Think about theories and evidence / Booster 5
Focus on forces – Forces all around
Extra lessons (not in Pupil book)
J3 The Solar System Extra lesson for Activity J3a / Review and assess progress (distributed appropriately)
Misconceptions
That only planets/moons with an atmosphere have gravity, because weight is caused by the atmosphere pushing down.
Satellites are in a region of zero gravity.
Health and safety (see activity notes to inform risk assessment)
Risk assessments are required for any hazardous activity. In this unit pupils use a fast-moving object to explore orbits.

© Harcourt Education Ltd 2004 Catalyst 3

This worksheet may have been altered from the original on the CD-ROM.