Being a scientist — fair tests, guesses and evidence

Tests: 7 of 13 right · Exam: 4 of 4 right · Kind: ★★★ · Understood: 14 of 17 · Run: 2026-10-18, commit f3c23ea72

Lesson 91 of the world course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: the lesson in the corpora.

Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: the lesson's questions in the corpora.

Test 1 · ★★★ · right ✓

Lily tests two paper planes, but one is bigger and she throws it harder. Why is this not a fair test?

1. Paper planes cannot be tested — no support
2. She should have used three planes — no support
3. Two things were changed, so she cannot tell which one mattered — ← Mova's choice · ✓ the right answer · score 5
4. She threw them on the same day — no support

Why: It took the question to ask why something happens (its cause). It chose option 3 with score 5, the only option with support. Its support: lesson 91, line 2: «In a fair test you change only one thing and keep everything else the same, so that if the result changes, you know which thing caused it.», reached through the option's own match among the sentences about the question's things. What matched: the same action «change» (+2); the same thing acted on «one thing» (+2); a different doer (counts against) (+1). · the question and its options parsed, with trees and pragmatics

Test 2 · ★★★ · wrong ✗

A boy wears his lucky socks and wins a race. He says the socks made him win. What is wrong with his thinking?

1. He should have measured the socks — ← Mova's choice · no support
2. One win together with the socks does not prove the socks caused it — ✓ the right answer · no support
3. Lucky things only work on Fridays — no support
4. Socks always make you slower — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 3 · ★★★ · right ✓

Ana tests a new plant food on one plant, which grows well. What would make her result more convincing?

1. Giving the plant twice as much food — no support
2. Testing many plants, with some getting no plant food — ← Mova's choice · ✓ the right answer · score 10
3. Telling everyone that it works — no support
4. Testing the same single plant again every month next year — score 10

Why: It took the question to ask what it is done to. It chose option 2 with score 10, tied with another option at 10 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 91, line 11: «Testing many plants or people is better than testing just one.», reached through the option's own match among the sentences about the question's things. What matched: the same action «test» (+5); it fills the role the question asks for (+3); the same thing acted on «many plants» (+2). · the question and its options parsed, with trees and pragmatics

Test 4 · ★★★ · right ✓

Which is the best reason to trust a scientific result?

1. Other people repeated the test and got the same result — ← Mova's choice · ✓ the right answer · score 5
2. It was written in big letters — no support
3. Many people would really like it to be true, so it must be — no support
4. A famous person said it was true — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 5, the only option with support. Its support: lesson 91, line 3: «You measure the results, repeat the test several times and look at all the evidence, even the results you did not expect.», reached through the same lesson line as the sentence the question matched. What matched: the same action «repeat» (+3); the same thing acted on «test» (+2). · the question and its options parsed, with trees and pragmatics

Test 5 · ★★★ · wrong ✗

Ben predicts that heavier balls fall faster. He drops a heavy and a light ball of the same size and they land together. What should he conclude?

1. His test must be broken — no support
2. The light ball must have been pushed — ← Mova's choice · score 9
3. His prediction was wrong for these balls — ✓ the right answer · no support
4. He should keep only the heavy ball result — no support

Why: It took the question to ask what it is done to. It chose option 2 with score 9, the only option with support. Its support: lesson 51, line 2: «When you kick a ball you push it, and when you open a drawer you pull it. A bigger force makes a bigger change.», reached through the option's own match among the sentences about the question's things. What matched: the same action «push» (+5); it fills the role the question asks for (+3); the same thing acted on «ball» (+2). Against it: a different doer (counts against) (-1). The right option, 3, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 6 · ★★★ · wrong ✗

To test whether sugar dissolves faster in hot water, what is the fair way?

1. Same amount of sugar and water, change only the temperature — ✓ the right answer · no support
2. Hot water with more sugar and cold water with less — ← Mova's choice · score 3
3. Stir only the cold cup — no support
4. Use a big cup for the hot water and a small cup for the cold — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 3, the only option with support. Its support: lesson 18, line 14: «Sugar dissolves faster in warm water and when it is stirred, and more of it can dissolve in hot water than in cold.», reached through the same lesson line as the sentence the question matched. What matched: the same place «hot water» (+2); the same property (+1). The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 7 · ★★★ · wrong ✗

In a town, children who own more books get better marks. What could explain this other than the books themselves?

1. Books always make children clever by themselves — no support
2. Books are given out as prizes for marks only — ← Mova's choice · score 4
3. Something else, like families who read together, causes both — ✓ the right answer · no support
4. Good marks make books appear at home — no support

Why: It took the question to ask what it is done to. It chose option 2 with score 4, the only option with support. Its support: lesson 48, line 5: «Great inventions changed life: the wheel about 5,500 years ago, writing about 5,000 years ago in Mesopotamia, and printing with movable metal letters by Johann…», reached through a sentence linked to the one the question matched. What matched: it fills the role the question asks for (+3); the same thing acted on «books» (+2). Against it: a different action (counts against) (-1). The right option, 3, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 8 · ★★★ · right ✓

Two pupils measure the same jump and get very different numbers. What should they do first?

1. Measure again carefully and check the method — ← Mova's choice · ✓ the right answer · score 8
2. Throw away both numbers for ever and pick a new jump — no support
3. Choose the number they like best — score 4
4. Add the numbers and stop — no support

Why: It took the question to ask what is done. It chose option 1 with score 8, against 4 for the next best. Its support: lesson 82, line 1: «Temperature tells us how hot or cold something is; we measure it with a thermometer in degrees Celsius (°C). Heat is energy that moves from a hotter thing to a…», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+5); the same action «measure» (+3). · the question and its options parsed, with trees and pragmatics

Test 9 · ★★★ · right ✓

Why does a scientist keep a control group in a medicine test?

1. Because the medicine needs company — no support
2. To make the test cheaper — score 3
3. To see what would happen without the medicine — ← Mova's choice · ✓ the right answer · score 4
4. To give the medicine to more and more people at once — no support

Why: It took the question to ask why something happens (its cause). It chose option 3 with score 4, against 3 for the next best. Its support: lesson 91, line 1: «A scientist starts with a question, makes a careful guess called a prediction, and then tests it to see whether the world agrees.», reached through the option's own match among the sentences about the question's things. What matched: the same action «see» (+2); the same doer «scientist» (+2). · the question and its options parsed, with trees and pragmatics

Test 10 · ★★★ · wrong ✗

my bean plant grew loads when i sang to it, so singing works?

1. Yes, plants always grow way more with music, everyone knows that — ← Mova's choice · score 5
2. Yes, one plant is enough proof — no support
3. Not proven; test many plants and keep a control without singing — ✓ the right answer · score 0
4. No, plants can never be tested — score 0

Why: It took the question to ask which statement is true. It chose option 1 with score 5, against 0 for the next best. Its support: lesson 25, line 4: «A chicken hatches from an egg as a fluffy chick that already looks like a small hen, and simply grows; a bean plant grows from a seed into a plant that flowers…», reached through the remembered sentence the question matched. What matched: the same action «grow» (+4); the same doer «bean plant» (+1). The right option, 3, scored 0. · the question and its options parsed, with trees and pragmatics

Test 11 · ★★★ · wrong ✗

gonna test which paper towel soaks up most, what do i keep the same

1. Only the time of day you test — ← Mova's choice · no support
2. Everything except the kind of paper towel — ✓ the right answer · no support
3. Nothing, just change everything at once and see — no support
4. Only the colour of the paper towels — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 12 · ★★★ · right ✓

Mia says if ur prediction is wrong the experiment failed. true?

1. No, a wrong prediction is still useful, because it teaches you something — ← Mova's choice · ✓ the right answer · score 9
2. Yes, you must change the results to match — no support
3. No, but you must never write it down — no support
4. Yes, a wrong prediction makes the test useless — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 9, the only option with support. Its support: lesson 91, line 13: «A wrong prediction is still useful, because it teaches you something.», reached through a sentence linked to the one the question matched. What matched: the same action «teach» (+4); the same thing acted on «something» (+3); the same doer «prediction» (+2). · the question and its options parsed, with trees and pragmatics

Test 13 · ★★★ · right ✓

a video said ice cream sales and sunburn go up together, so ice cream gives u sunburn. right?

1. Yes, ice cream makes skin burn faster — score 1
2. No, two things happening together does not prove one causes the other — ← Mova's choice · ✓ the right answer · score 7
3. Yes, because both happen in summer — score 3
4. No, sunburn makes people buy ice cream — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 7, against 3 for the next best. Its support: lesson 91, line 4: «Two things happening together does not prove that one causes the other: more ice creams and more sunburns both happen in summer, but ice cream does not cause s…», reached through the same lesson line as the sentence the question matched. What matched: the same action «happen» (+3); the same doer «two things» (+3); the same property (+1). · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Which of the following statements most accurately characterises a fair test?

1. The result is decided before the test — no support
2. Only one thing is changed and everything else is kept the same — ← Mova's choice · ✓ the right answer · score 8
3. Every condition is changed at the same time — no support
4. Nothing whatsoever is changed — no support

Why: It took the question to ask who or what does it. It chose option 2 with score 8, the only option with support. Its support: lesson 91, line 7: «In a fair test only one thing is changed and everything else is kept the same.», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «one thing» (+5); the same action «change» (+3). · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · right ✓

Identify the purpose of a control group in an experiment.

1. It decides the prediction to be tested — no support
2. It records the results on behalf of others — no support
3. It is kept without the change so the results may be compared — ← Mova's choice · ✓ the right answer · score 5
4. It receives the greatest amount of the change under examination — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 5, the only option with support. Its support: lesson 91, line 9: «A control group is kept without the change so you can compare the results with it.», reached through the option's own match among the sentences about the question's things. What matched: the same action «compare» (+3); its «because» matches the remembered cause (+2). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · right ✓

It is given that two things are observed to occur together. Determine the conclusion which may properly be drawn.

1. It is not thereby proved that one causes the other — ← Mova's choice · ✓ the right answer · no support
2. It is thereby proved that the second causes the first — no support
3. It is thereby proved that neither has any cause — no support
4. It is thereby proved that the first causes the second — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · right ✓

Select the response that is consistent with the established facts concerning the conduct of scientists confronted with good new evidence.

1. They change their minds when it shows them to be wrong — ← Mova's choice · ✓ the right answer · score 6
2. They disregard it in favour of their earlier, firmer beliefs — no support
3. They conceal it from other scientists — no support
4. They repeat their former claims more firmly — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 6, the only option with support. Its support: lesson 91, line 15: «Scientists change their minds when good new evidence shows they were wrong.», reached through the remembered sentence the question matched. What matched: the same action «change» (+4); the same doer «scientists» (+1); the same thing acted on «minds» (+1). · the question and its options parsed, with trees and pragmatics

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/world/91-being-a-scientist/