Year 7 Science · Unit 4 · Lesson 1
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Learning Goals
Fill the gap
Choose words from the word bank. Each word is used at most once. Two words are not needed: cross them out.
The purpose of science is to build knowledge and understanding of the world. When a scientist notices and records what is happening, that is . Running a fair test that changes one thing is . Looking carefully at the results to work out what they mean is . The three steps form a , so each lap adds to what we know. A scientific claim must be supported by , but an does not have to be. A project that combines biology, chemistry and physics to solve one problem is called science.
1. Scientists protecting the Great Barrier Reef ask many questions. Write the branch of science (biology, chemistry, physics or geology) that each question belongs to.
| Question a scientist is asking | Branch |
|---|---|
| (a) How much more acidic has the seawater become as it takes in carbon dioxide? | |
| (b) How deep does sunlight reach into the water over the reef? | |
| (c) Which fish return to a patch of reef after the coral has bleached? | |
| (d) What minerals make up the limestone rock under the reef? | |
| (e) How fast do ocean currents carry warm water across the reef? |
Cause and effect: the stomach ulcer discovery
In the 1980s most doctors were sure that stress and spicy food caused stomach ulcers. Fill the three empty boxes. Each box is caused by the one before it, and each row carries on from the end of the row above.
2. Use your answers to Question 1 to explain why protecting the reef is called interdisciplinary science.
Read the data: a reef survey
Scenario
After a hot summer, a reef team dives at five sites. At each site they record the highest water temperature measured that summer and the percentage of the coral they checked that had bleached (turned pale). They do not change anything at the sites; they only watch and record.
| Site | Highest water temperature (°C) | Coral bleached (%) |
|---|---|---|
| A | 29.0 | 35 |
| B | 27.5 | 5 |
| C | 30.5 | 70 |
| D | 28.5 | 20 |
| E | 30.0 | 60 |
Source: made-up survey results for this worksheet.
3. Name the warmest site and the site with the least bleaching. Then describe the pattern that links water temperature and bleaching.
4. Mila says: “This survey proves that warm water causes bleaching.” (a) Did the team use observation or experimentation at the reef? Give a reason. (b) Describe an experiment that would test whether warmer water causes coral to bleach.
5. A friend says: “Wearing a copper bracelet keeps you healthy. Everyone knows it.” Explain why this is not a scientific claim yet. Then describe how observation, experimentation and analysis could test it.
Fill the gap
observation; experimentation; analysis; cycle; evidence; opinion; interdisciplinary. Not used: luck, theory.
Question 1
(a) chemistry; (b) physics; (c) biology; (d) geology; (e) physics. All five correct = 3; three or four = 2; one or two = 1. [3 marks]
Cause and effect: the stomach ulcer discovery
Box 1: they suggest the bacterium, not stress, causes ulcers (1). Box 2: Marshall drinks the bacteria himself to test the idea (experimentation) (1). Box 3: he concludes the bacterium causes the illness and antibiotics can cure it (analysis) (1). [3 marks]
Question 2
The questions need chemistry, physics, biology and geology, not just one branch (1). Interdisciplinary science combines several branches to understand one problem, and no single branch could protect the reef alone (1). [2 marks]
Question 3
Warmest: site C (30.5 °C); least bleaching: site B (5%) (1). The higher the summer water temperature, the more of the coral had bleached (1). [2 marks]
Question 4
(a) Observation: they only watched and recorded (1). (b) Keep the same kind of coral in several tanks and change only the water temperature (1); keep light and water the same, and measure how much coral bleaches in each tank (1). [3 marks]
Question 5
Marking guide: 1 “everyone knows it” is belief, not evidence; 1 a scientific claim needs evidence and must be testable; 1 experiment: one group wears copper bracelets, a similar group wears look-alike non-copper ones; 1 everything else kept the same (similar people, same months); 1 observation: record days each person is sick; 1 analysis: compare the groups; no real difference means the claim is not supported. [6 marks]
Model answer: “Everyone knows it” is belief, not evidence; a scientific claim needs evidence and must be testable. One group of similar people would wear copper bracelets and another would wear look-alike bracelets that are not copper, for the same three months, so only the bracelet changes. I would record how many days each person is sick, then compare the groups. If there is no real difference, the claim is not supported.
Common error: treating a pattern seen in a survey as proof of a cause without an experiment.