Year 8 Science · Unit 1 · Lesson 18
Challenge Worksheet
Learning Goals
Find the mistake
A student wrote this investigation report
Question: How does exercise affect breathing rate?
Prediction: I think breathing rate will increase after exercise because the body needs more gas exchange.
Method: I counted my breaths for one minute at rest, after running around the oval once, and then after sitting for 5 minutes.
Data collected: Resting: 14 breaths/min. After exercise: 24 breaths/min. After recovery: 17 breaths/min.
Pattern: The numbers were 14, 24 and 17.
Conclusion: Exercise is good for you and makes you healthier. I predicted breathing would go up and it did, so my prediction was right. Therefore, everyone who exercises will have a healthy breathing rate.
1. Identify at least two problems with this student's report. Look especially at the Pattern and Conclusion sections.
2. Rewrite the Pattern and Conclusion sections of the report so they are scientifically correct. Your Pattern should describe the trend in the data using specific numbers. Your Conclusion should be based on that pattern and link it to the living system being investigated, without going beyond what the data shows.
3. Why is it a problem to say "my prediction was right, so the investigation worked"? What does the lesson say about the relationship between predictions and conclusions?
1. Scientists at the Australian Museum count frog populations across many sites over many years. They use this data to write conclusions about population health. Using the investigation framework from this lesson, explain which steps of the investigation process are most important for making sure their conclusions are trustworthy. Explain the purpose of each step you identify.
2. Explain why the conclusion step in a scientific investigation is described as "based on data, not opinion." What makes a conclusion stronger or weaker in a living-systems investigation?
Wrap Up
In one sentence, what was the main idea of this lesson?