These seven questions are original. Each one uses a health setting as context, and each one only needs syllabus science. Write your own answer first, then open the model answer.
The skills come from health-themed science without medical advice, part of chemistry in health contexts. Try them against the clock with the timed original practice session builder.
Questions 1 to 3: reading data without diagnosing
Question 1. A class records the resting pulse of 6 volunteers before and after 2 minutes of skipping.
Before (beats per minute): 72, 68, 75, 70, 66, 74. After: 118, 110, 125, 112, 104, 121.
Calculate the mean increase and state one conclusion the data supports.
Answer
Mean before = 425 ÷ 6 ≈ 71. Mean after = 690 ÷ 6 = 115. The mean increase is about 44 beats per minute (115 − 71).
A valid conclusion: in this group, 2 minutes of skipping raised the pulse rate. The data does not say whether any one volunteer is fit or unwell, so no statement about a person’s health is supported.
Question 2. A graph in a textbook shows the sugar level in the blood of an imaginary person rising after a meal and then falling. A student writes, “This person has a sugar problem.” Explain why this sentence is not a valid conclusion.
Answer
The graph shows a rise and then a fall, which is a normal pattern for a model person after eating. The graph has no reference range and no repeat readings, so it cannot identify a condition.
A valid sentence: after the meal the graph rises, then falls back towards where it started.
Question 3. In a class questionnaire, students who drink more water report fewer headaches. Give two reasons the questionnaire cannot show that water prevents headaches.
Answer
Any two of these earn the marks:
- The questionnaire shows a link, not a cause. Sleep, screen time or stress may differ between the two groups.
- Students state their own headaches, which is not a measured value.
- The questionnaire does not say how much water is “more”, or over how many days.
Questions 4 to 7: mechanism, limits and sources
Question 4. Name the process by which oxygen passes from the air sacs in the lungs into the blood, and explain why the thin walls of the air sacs help.
Answer
The process is diffusion, movement from a region of higher oxygen concentration to a lower one. Thin walls make the distance short, so oxygen crosses faster.
This explains how the lungs work. It does not tell anyone how to treat a breathing problem.
Question 5. A poster says, “Drink this herbal mix daily to clean toxins from your body.” Write two questions a scientist would ask before accepting the claim.
Answer
Two good questions: (1) Which toxins, and how were they measured before and after? (2) Was the mix compared with a control group that did not take it?
A third acceptable question asks who funded the test and whether it was repeated by others.
Question 6. A model of the heart in a textbook shows four chambers as simple boxes. State one thing the model explains and one thing it cannot show.
Answer
It explains that blood moves through separate chambers in a fixed order. It cannot show the muscle’s size, the valves opening in time, or how the real heart responds to exercise.
The limit of a model is part of the answer, not a fault in it.
Question 7. Decide which of these claims needs a current, authoritative health source before anyone repeats it: (a) the stomach contains acid, (b) a particular dose of a named medicine is safe for a child, (c) enzymes work best at an optimum temperature.
Answer
Claim (b) needs a current authoritative source, such as the Ministry of Health or a pharmacist. Doses depend on age, weight and other conditions, and advice changes.
Claims (a) and (c) are stable syllabus facts that a textbook can support.
If you got these wrong, where do you go next?
Mixing up a link with a cause points to distinguishing scientific evidence from marketing claims. Trouble with questions 6 and 7 points to recognising the limits of a classroom example.
Log each slip in the mistake log and paper-error review so a pattern shows up. If you want a teacher to read your answers with you, see online one-to-one Science tuition.