Weighing Evidence and Claims: a skill companion
A small set of reusable sheets that grow one inquiry skill: reading a method, a result or a claim with a critical eye, and naming what it assumes, what could have gone wrong, what evidence disagrees with it, and what it leaves unanswered. Print the scaffolds once and slot them into the science lessons you already teach.
What a skill companion is
Inquiry skills are not a topic of their own. They grow inside the science units a class teaches all year, such as Classifying Living Things, Energy Flow in Ecosystems, Earth, Sun and Moon, Balanced and Unbalanced Forces, The Particle Model of Matter, and Pure Substances and Mixtures. So this pack is not a full term of lessons. It is three reusable scaffolds, a map of where they fit, and a short stand-alone lesson for teaching the skill on its own first.
Start here: five minutes
- Read the pairing map on the next page: it shows which scaffold fits which science lesson.
- Print the report checker and the conflicting-evidence sheet, one each per student, whenever a class reviews results.
- Cut out the cards once. They are reused all year, and the blank cards fit any topic.
- Open the free interactive unit on your board when you want a worked example of the skill.
- Run the one-page mini-lesson first if you want to teach the skill before folding it into a topic.
No science background needed
Each scaffold explains itself in plain words, and the answer sheet gives a marked copy of the report, the reason the two groups disagree, the card key and a quick three-level guide. The step up from Year 6 is naming the kind of weakness: an assumption taken for granted, a source of error in the method, evidence that conflicts, or a question the work leaves open, and then rewriting the conclusion so it claims only what the evidence supports.
Slot the skill into your science lessons
Every science unit meets claims and methods worth questioning. This map shows one in each Year 7 topic, what to look for in it, and which scaffold to reach for. You do not run these as extra lessons; you fold them into the science you teach.
| When you teach | Claim or method | What to look for | Scaffold to slot in |
|---|---|---|---|
| Classifying Living Things (AC9S7U01) | A claim that a class key “works for every Australian beetle”, tested on six beetles | An assumption about the beetles left out, and the unanswered question of which kinds would break the key | Report checker |
| Energy Flow in Ecosystems (AC9S7U02) | A report that kangaroo numbers doubled after dingoes were kept out, from one property’s counts | Other changes in those years, such as rain, that could explain the rise, and counts from other places | Report checker, then the cards |
| Earth, Sun and Moon (AC9S7U03) | A claim that the moon is bigger near the horizon, judged by eye | A source of error: measured at arm’s length with a ruler, the moon is the same size in both places | The mini-lesson, then the cards |
| Balanced and Unbalanced Forces (AC9S7U04) | A conclusion that heavier cars roll further, when the heavy car started higher | A second variable that changed, and one trial each | Report checker |
| The Particle Model of Matter (AC9S7U05) | Two groups who disagree on whether salt makes ice melt faster | Differences in their methods, such as cup size or how the ice was measured, that explain the conflict | Conflicting evidence |
| Pure Substances and Mixtures (AC9S7U06) | A label claiming a water filter removes “all impurities” | What was tested, what was not, and the questions a buyer should ask | Report checker, then the cards |
| Any science topic | Any report, result or claim | What was assumed, what could have gone wrong, what disagrees with it, and what it leaves open | Report checker first |
The three moves, and the picture that backs each one
When you want a worked example on the board, open the interactive unit and use the picture that matches the move.
- Separate real evidence from assumptions and flaws: “Which statements really back the claim?”.
- Find a source of error hiding in the raw data: “Spot the reading that hints at an error”.
- Find the untested assumption in a method: “Was only one thing allowed to change?”.
How the scaffolds build the skill
The report checker reads a short report and names an assumption, a source of error, the conflicting evidence and an unanswered question, then rewrites the conclusion. The conflicting-evidence sheet compares two groups who reached opposite answers, finds the difference in their methods, and designs a test that would settle it. The cards sort statements from many investigations into assumptions, sources of error and unanswered questions.
Check a report before you trust it
A conclusion is only as strong as the method behind it. Read Class 7G’s report, then name its weaknesses and rewrite the conclusion so it claims only what the evidence supports.
Class 7G’s report
- We let a light car (40 g) and a heavy car (120 g) roll down our ramp onto the classroom floor, once each.
- The heavy car would not fit at the top of the ramp, so we let it go from halfway up a steeper part.
- We measured how far each car rolled from the end of the ramp with a tape measure.
Also known: Another class found their light car rolled further than their heavy car on carpet.
Name the weaknesses
| An assumption | |
| A possible source of error | |
| Conflicting evidence | |
| An unanswered question |
A better conclusion
Teacher note: a better conclusion is smaller, not braver. It says what was found, under which conditions, and what is still unknown.
Two groups, one question, opposite answers
When two investigations disagree, neither result is simply thrown away. Compare the methods: a difference between them often explains the conflict, and points to the test that would settle it.
A. The results
Question: Do bean seeds sprout faster in the dark? Each group planted 10 bean seeds in the dark and 10 in the light, and recorded the mean number of days until a shoot appeared.
| Group | Seeds in the dark | Seeds in the light | What they concluded |
|---|---|---|---|
| Group A | a dark kitchen cupboard, 22 °C: 5 days | a bright kitchen windowsill, 22 °C: 5 days | Light makes no difference. |
| Group B | a dark garage, 12 °C: 9 days | a bright classroom windowsill, 22 °C: 5 days | Seeds need light to sprout quickly. |
B. Explain the conflict
C. Settle it with a fair test
Assumption, error, or unanswered question?
Each card comes from a different investigation. Cut out the cards, lay down the three grey heading cards, and sort the statements under them. For each one, say how the investigation could be improved.
Teacher note: four cards go in each pile. The answer sheet lists which is which, and why.
The flawed cup test
Use this stand-alone lesson to teach the skill on its own, before you fold it into a science topic. You run a cooling test with a hidden flaw: the cup wrapped in a tea towel starts with hotter water. The result looks convincing until the class starts asking about the method.
We are learning to
- find the assumptions and sources of error in a method,
- explain how a flaw can produce a convincing but untrustworthy result,
- rewrite a conclusion so it claims only what the evidence supports.
Success criteria
- I can name an assumption, a source of error and an unanswered question in a test.
- I can explain why the cup test does not show that the tea towel keeps water warm.
You need
- two identical cups, a tea towel, two thermometers and a kettle; you pour, and students stay back from the hot water,
- the report checker (scaffold 1), one per student, and the cards from scaffold 3, one set per table.
Lesson flow (about 30 minutes)
| 5 min | Evidence or not? Show the board (see the box). Ask: “Which of these statements was actually measured, and which was just taken for granted?” |
| 10 min | The test Without telling the class, fill the wrapped cup with water at about 70 °C and the bare cup at about 50 °C. While they cool, students start the report checker. After 10 minutes, read both thermometers. Ask: “So does a tea towel keep water warm? How sure are you?” |
| 10 min | Pick it apart Students question the method; reveal the starting temperatures only when someone asks for them. Ask: “What did we take for granted? What could we still not answer, even with a fair start?” |
| 5 min | Sort the cards Tables sort the cards under the three heading cards. Ask: “For this card, what would you change in the investigation?” |
Running it shorter? Stop after picking the test apart, and finish the report checker in your next science lesson.
Watch for these ideas
- Accepting a result because it matches what they expected.
- Calling every weakness “human error” instead of naming what went wrong and how it shifted the result.
- Throwing out a whole result over one flaw, instead of saying what it can and cannot show.
Make it easier, make it bigger
- Easier: give the four headings of the report checker as questions to ask about the test.
- Bigger: rerun the test fairly, with both cups starting at the same temperature, and compare the result.
Answers and look-fors
The next sheet has a marked copy of Class 7G’s report, the reason the two germination groups disagree, the card key and a quick three-level guide. In the cup test, the wrapped cup started about 20 °C hotter, so it would still be warmer after 10 minutes even with no towel at all.
Answers and look-fors
Report checker: Class 7G’s report, marked
| An assumption | That the two cars differ only in mass, when their wheels and axles may rub differently. |
| A possible source of error | The heavy car started from a different place on a steeper part of the ramp, and each car rolled only once, so one odd roll decides the result. |
| Conflicting evidence | The other class’s light car rolled further on carpet, which the conclusion does not explain. |
| An unanswered question | Would the result hold for other cars, other floors, or the same starting point? |
A better conclusion: “In our one test on a classroom floor, the heavy car rolled further, but it also started from a different place, so we cannot yet say whether its mass caused the difference.” The original claim, “always, on every surface”, reached far past one test on one floor.
Conflicting evidence: the bean seeds
Group A kept both sets of seeds at 22 °C and found no difference (5 and 5 days). Group B put its dark seeds in a garage at 12 °C and its light seeds at 22 °C, so it changed the temperature as well as the light; the slower sprouting (9 against 5 days) can be explained by the cold. Group B assumed, without checking, that the garage was as warm as the classroom. Group A’s evidence supports its conclusion better: in a fair comparison, light made no difference to how fast the seeds sprouted. A fair test changes only the light, keeps the temperature, seeds, soil and water the same, and measures the days until a shoot appears. Still unanswered: whether light matters once the seedlings start to grow, which it does for making food.
Weakness cards
| Card | Statement | Pile | Why |
|---|---|---|---|
| A | We took for granted that all the seeds were equally healthy. | An assumption | Never checked. |
| B | The stopwatch was started a moment after the ball was let go. | A source of error | Every time comes out short. |
| C | Would the same result happen with a different kind of seed? | An unanswered question | Only one kind was tested. |
| D | Does the pattern continue beyond the largest mass we tested? | An unanswered question | Outside the range measured. |
| E | We assumed the tap water was the same temperature in every cup. | An assumption | Never measured. |
| F | The ruler was read from above, not at eye level. | A source of error | Reading at an angle shifts the value. |
| G | The ramp was nudged between the third and fourth trials. | A source of error | The later trials ran on a different ramp. |
| H | Was the difference bigger than the normal spread between repeats? | An unanswered question | Not yet compared with the spread. |
| I | We assumed the thermometer read correctly without checking it in ice water. | An assumption | Its zero was never tested. |
| J | We assumed all the slaters we counted were the same kind. | An assumption | Never identified. |
| K | What happens to the plants after four weeks, not two? | An unanswered question | Beyond the time studied. |
| L | One measuring cylinder was filled past the mark. | A source of error | That cup had more water than the rest. |
A quick three-level guide
| Move | Working towards | At standard | Beyond |
|---|---|---|---|
| Spot weaknesses | says the test was wrong without saying how | names an assumption, a source of error and an unanswered question | explains which way each weakness would push the result |
| Weigh conflicting evidence | picks the result they prefer | finds the difference in method that explains the conflict | designs the fair test that would settle it |
| Rewrite the conclusion | keeps the broad claim | limits the claim to what was tested, and says what is still unknown | suggests the next investigation that would extend the claim |
A student at standard names the weaknesses in a method, explains a conflict between results, and rewrites a conclusion to fit the evidence. The skill grows all year, so keep the scaffolds coming back whenever a class reviews its own or others’ work.