Year 7 Science · Unit 4 · Lesson 7
Apply Worksheet
Learning Goals
1. “Geo” and “helio” come from Greek words. Say what each one means, and use it to state what sits at the centre of each model.
Order the steps: how the model of the Solar System changed
Number the events from 1 (first) to 5 (last).
| Order (1–5) | Event |
|---|---|
| Copernicus suggests that the planets, the Earth included, go round the Sun; at first nobody can test it. | |
| Astronomers give up the old picture and accept the new one. | |
| People watch the Sun cross the sky and do not feel the Earth move, so they picture a still Earth at the centre. | |
| A telescope shows moons orbiting Jupiter and a full set of phases of Venus. | |
| Ptolemy records a detailed version of the old picture in a book. |
Compare the two models
Complete the table. One mark for each row with both cells correct.
| Question | Geocentric model | Heliocentric model |
|---|---|---|
| What sits at or near the centre? | ||
| What moves around what? | ||
| Scientist and year | ||
| Why does the Sun seem to cross the sky each day? |
2. Ptolemy wrote down the geocentric model around 150 CE. Galileo’s telescope evidence came around 1610. For about how many years was the geocentric model trusted before that evidence arrived? Show your working.
Answer years
Cause and effect: Jupiter’s moons
Fill the two empty boxes. Each box is caused by the one before it, and row 2 carries on from the end of row 1.
Read the data: the shapes of Venus
Scenario: an astronomy club
A school astronomy club looked at Venus through a small telescope once a month for most of a year and drew the lit part they could see. Table 1 shows their records.
| Month | January | April | August | September | October |
|---|---|---|---|---|---|
| Shape seen | Nearly full disc | More than half lit | Half lit | Thick crescent | Thin crescent |
Source: made-up but realistic observations for this worksheet.
3. Describe the pattern in Table 1. Which object in the sky shows a similar pattern of shapes?
4. Galileo saw this same full set of phases around 1610. Which model does this evidence support? Explain what it did to the other model.
5. Zara says: “The old scientists were silly for believing the Earth was at the centre.” Evaluate Zara’s claim, using the idea of evidence.
Question 1
Geo means Earth, so the Earth is at the centre of the geocentric model (1). Helio means Sun, so the Sun is at the centre of the heliocentric model (1). [2 marks]
Order the steps: how the model of the Solar System changed
Reading down the table as printed, the correct step numbers are 3, 5, 1, 4, 2. In order: people picture a still Earth; Ptolemy writes the model; Copernicus publishes his idea; the telescope evidence; the geocentric model is rejected.
Compare the two models
Centre: Earth / Sun (1). Motion: everything moves around a still Earth / the Earth and planets orbit the Sun (1). Ptolemy, about 150 CE / Copernicus, 1543 (1). Sun crossing the sky: the Sun really moves / the Earth spins, so the Sun only appears to move (1). [4 marks]
Question 2
1610 − 150 (1) = 1460 years (1). [2 marks]
Cause and effect: Jupiter’s moons
Box 1: the points of light are moons orbiting Jupiter (1). Box 2: so not everything in the sky orbits the Earth (1). [2 marks]
Read the data: the shapes of Venus
3. Venus goes from a nearly full disc to half lit to a thin crescent: a full set of phases (1). The Moon (1). [2 marks]
4. The heliocentric model (1). Only the Sun-centred model could produce a full set of phases (1), so this evidence helped reject the geocentric model (1). [3 marks]
Question 5
Marking guide: 1 position (Zara is not right); 1 each for two pieces of everyday evidence (the Sun crossing the sky; the stars wheeling; no feeling of motion); 1 they had only their eyes, no telescope; 1 the telescope showed Jupiter’s moons and Venus’s phases, which the old model could not explain; 1 changing a model for evidence is a strength, as understanding improves. [6 marks]
Model answer: Zara is not right. With eyes alone, the Sun seems to cross the sky and we do not feel the Earth move, so the Earth-centred model fitted the evidence. When the telescope showed Jupiter’s moons and Venus’s phases, the model changed, and changing for new evidence is a strength of science.
Common error: saying the model changed because the new idea was more popular.