Year 7 Science · Unit 4 · Lesson 3
Master Worksheet
Learning Goals
1. Give two reasons why a planned fair test gives a more trustworthy answer than a guess.
Find the error
Aria’s investigation report
Question: Does the height of a ramp change how far a toy car rolls along the floor?
Hypothesis: The car rolled 2.4 m from the highest ramp.
Method: Roll the car from ramps 10, 20 and 30 cm high, using a heavier car for each new height.
Results: I watched the runs, and later at home I wrote down that the higher ramps seemed to go further.
Communicate: I shared my method and results table with the class so they could repeat my test.
2. Three of Aria’s five sections contain one error each. Name each wrong section, say what is wrong, and rewrite it correctly.
Plan an investigation: a wind-up toy
Plan a controlled experiment to answer: “Does the number of times you turn a wind-up toy’s key change how far the toy travels?” Test four numbers of turns.
Hypothesis
Variables
Method (3 steps)
Results table: write the column headings (with units) and fill in the first column
Read the data: paper helicopters
Scenario
Another class asks: “Does the number of paper clips on a paper helicopter change how long it takes to fall 2 m?” They use the same helicopter design each time, drop it from the same height and time three drops for each number of clips.
| Paper clips | Drop 1 | Drop 2 | Drop 3 | Average |
|---|---|---|---|---|
| 0 | 2.4 | 2.5 | 2.3 | 2.4 |
| 1 | 2.0 | 1.9 | 2.1 | 2.0 |
| 2 | 1.7 | 1.2 | 1.8 | |
| 3 | 1.5 | 1.4 | 1.6 | 1.5 |
Source: sample class results for this worksheet.
3. One result in Table 1 does not fit the pattern. Identify it and suggest a cause. Then calculate the average for 2 clips without it, and write it in the table.
Average for 2 clips s
4. Write a conclusion that answers the class’s question. Quote data from Table 1.
5. An advert says: “Grip-X shoes are scientifically proven to grip better. Our tester wore them for one game and felt that he slipped less.” Evaluate the advert’s claim, and describe a better test.
Question 1
Any two, 1 mark each: only one thing changes, so you know what caused the result; it is repeatable, so others can check it; repeating and recording removes lucky accidents; a guess can be wrong with no way to know. [2 marks]
Find the error
2. Hypothesis: a result, not a prediction; e.g. “I predict the car rolls further from a higher ramp” (1). Method: two things change (height and car); use the same car (1). Results: casual and from memory; measure each distance with a tape measure and record it in a table as you go (1). Question and Communicate are correct. [3 marks]
Plan an investigation: a wind-up toy
Hypothesis: the more turns, the further the toy travels (1). Variables: change the number of turns; measure the distance travelled; keep the same toy, floor surface and start line (1). Method: turn the key a set number of times and release the toy at the start line without pushing; measure the distance with a tape measure; repeat three times for each number of turns (1). Headings: Number of turns | Distance, three runs (cm) | Average distance (cm) (1); first column four numbers, e.g. 2, 4, 6, 8 turns (1). [5 marks]
Question 3
1.2 s (2 clips, drop 2) (1). Cause: e.g. the stopwatch started late or stopped early, or a lower drop (1). (1.7 + 1.8) ÷ 2 = 1.75, about 1.8 s (1). [3 marks]
Question 4
Yes: the more paper clips, the shorter the time to fall 2 m (1), from an average of 2.4 s with no clips to 1.5 s with three (1). [2 marks]
Question 5
Marking guide: 1 not proven; 1 “felt” is a casual observation, not a measurement; 1 one person, one game: not repeated, could be luck; 1 no fair comparison with other shoes; 1 better test: any controlled test that changes only the shoe and measures grip, e.g. same mass in each shoe, pulled across the same floor with a spring scale; 1 repeat, record in a table as you go, and share the method. [6 marks]
Model answer: The claim is not proven. “Felt he slipped less” is a casual observation, and one tester in one game could be luck, with no fair comparison with other shoes. Better: put the same mass in each shoe and pull it across the same floor with a spring scale, changing only the shoe. Test each three times, record in a table, and share the method so others can repeat it.
Common error: writing a result as the hypothesis.