Science at key stage 3    (Year 7)

• Pose these questions about time so pupils can review their knowledge and understanding of the relationship between Sun, Earth and Moon. Ask them to represent the system as a model made up from, eg a light source, football and tennis ball, and to use the model to explain the phenomena. Ensure that they can correctly identify the Sun, Earth and Moon in this model. Show pupils photographs, video clips, CD-ROMs and simulations to reinforce their knowledge.
• Challenge pupils to answer questions, eg
• Which way is 'down' in Australia?
• How do we know the Earth is a sphere and not flat?
• Why are there time zones?

• Ask pupils to recall the difference between light sources and reflective surfaces. Discuss evidence that the Sun emits light (as a star) and that the Moon does not. Ask them whether or not the Moon and the Earth are light sources like the Sun. Discuss their evidence.

• Provide pupils with images showing how the Moon changes shape over a 28-day period. Ask them to sequence these and help them to explain this in terms of the Sun as a light source. Encourage pupils to use models and images to improve their explanation, eg half-black polystyrene sphere on a stick moved around at head height.
• Show an image of the Earth taken from the Moon. Ask pupils if a Moon dweller would see the apparent 'phases of the Earth'.

• Remind pupils of the solar eclipse of 1999. Ask them to explain what caused this using diagrams and models, eg involving a light source, football, tennis ball, and ICT simulations. Challenge pupils to think about this, and to suggest answers. Clarify the importance of the slight angle of the Moon's orbit relative to that of the Earth, and use this to explain the rarity of total eclipses. Help pupils to adapt their own diagrams of these phenomena to the scientific model.
• Extend to lunar eclipses. Provide pupils with an explanation of what these involve. Ask them to use their models to represent the process.
• Review this work by providing a set of diagrams showing stages of an eclipse, and ask pupils to put them in the correct sequence.
• Ask pupils to find out about some of the research projects based around the 1999 (or other) solar eclipse.

• Use a video to show a solar eclipse and ask pupils to write about what it would be like to experience this event, describing the stages of the eclipse with accompanying pictures, eg in the style of a news report. Alternatively, ask pupils to find out or imagine how people in the past have interpreted the events of an eclipse.

• Ask pupils about any work carried out at key stage 2 on seasonal variation, eg changing hours of daylight throughout the year. Ask them for an explanation of this. Help pupils model the idea of the tilt of the Earth. Ask pupils to suggest ways in which the seasons differ from each other, eg position of Sun in the sky, climate.

• Help pupils to use a datalogger to test the validity of the 'tilted Earth' explanation of the seasons, eg by placing a tilted globe at a distance from a source of light/ heat and using a heat sensor to monitor the change in temperature as it is moved from the north to the south pole along a line of longitude. Record and display the data as a graph for analysis and interpretation by pupils.
• Position the globe with Britain in a summer position relative to the light-source 'Sun'. Place a light sensor on one point and slowly rotate the globe. Collect data illustrating the differing hours of day length in summer and winter positions, and how this is dependent on the orientation of part of the globe to the 'Sun'.
• Provide pupils with secondary data about seasonal changes, eg temperature, day length. Ask pupils to use both sources of data to relate seasonal changes to the model of the Sun, Earth and Moon system that they have developed.

• Ask pupils to imagine that they are visitors to Earth from a planet in another part of the universe, which orbits and spins more slowly. How would their world be different from Earth? Ask them to write a scientific report to their home planet describing some of the new phenomena observed on their mission, eg day length, year length, seasons, phases of the Moon and eclipses.
• This could be extended by telling pupils that this other planet is not tilted and that its moon is much further from the planet. Help pupils to model the system and extend their account to seasons, eclipse and phases of the Moon.

• Elicit pupils' knowledge and understanding of the solar system. Ask them to name the planets they know and the order in which they occur from the Sun. Pupils could devise a mnemonic to memorise the planets in order. Brainstorm other information about the planets. Ask them to label the planets on a diagram, which includes the asteroids and natural satellites of the planets. Ask them what they think these other bodies might be made of.
• Discuss how astronomers obtain evidence of planets and other bodies in the solar system by use of telescopes and probes. Raise the importance of the size and positioning of the instrument, eg William Herschel, who discovered Uranus, built the largest mirror of his time in his kitchen. Ask pupils to use secondary sources to find out about the discoveries of William and his sister Caroline, and how they changed ideas about the solar system and the universe.
• Ask pupils what they think it would be like on other planets. Encourage them to think about how it would be different from Earth, eg surface, temperature, atmosphere, day length, year length. Ask pupils to search secondary data sources on the planets, eg books, internet and CD-ROMs, and, eg write a travel brochure for future visitors to the chosen planet, identify 10 things you want to know about a planet and find the answers.

• Present pupils with information about the planets in the solar system, in the form of a spreadsheet. Show pupils how to sort the information, eg mass, diameter, distance from Sun, number of moons, length of year, length of planetary day, on the spreadsheet and how to use the applications to sort data and draw graphs. Ask them to draw conclusions from their graphs and explain to other pupils how strong they think the evidence is for these conclusions.

• Ask pupils to consider the evidence collected about the solar system in the previous activities and to use it to support a discussion about the possibility of life existing on other planets. If necessary prompt with questions, eg
• What conditions are necessary for life forms to survive?
• Do any planets have these conditions?
• What evidence would we look for in searching for life?
• What is so special about Earth that it supports life?
• Help pupils to record the main points from the discussion and to evaluate how good their evidence is.

• Remind pupils of earlier work on the Sun as a light source and ask questions to elicit pupils' knowledge about stars. Ensure that they understand how stars are different from planets, and that the Sun is a star.
• Invite pupils to think of questions to answer about the stars, eg
• Where are the stars?
• Why do we only see other stars at night?
• How did sailors and desert travellers use stars to navigate?
• Present evidence, eg from time-lapse photography images, to show how the stars appear to move across the night sky. Remind pupils of work carried out at key stage 2 concerning the apparent movement of the Sun in the sky, and help them to use this idea to explain the apparent movement of stars. Relate the movement of the Earth round the Sun to the changes in visible stars during the year, eg with a model planetarium.

• Ask pupils to make up questions on topics of this unit for a quiz. They could be presented in various ways, eg as bingo or in the style of a TV quiz show, and played according to the agreed rules.