Topic ladders · Across Subjects
A Seed
One topic, four rungs: from Classes 1–3 to Classes 11–12. Start at your own stage, or climb from the bottom. Every rung follows the same six steps: Notice, Guess, Try, Observe, Explain, Ask another question.
Small test in each rung: scroll down to the end of your rung for five short questions that check what you have learnt. Tap an answer, then press Check answer.
Print the family table: all four rungs side by side on one sheet, so everyone at home can find their own rung.
Choose your class stage
Rung 1 · Classes 1–3
Seed Detectives: Sort and Explain
Before you start: safety and help
For the grown-up who helps.
- Safety: Seeds are for looking at and touching, never for eating. Raw rajma is harmful if eaten raw. Never use castor seeds or ratti seeds (bright red with a black spot): they are poisonous.
- Safety: Keep small seeds away from babies and toddlers, and make sure nothing goes into a mouth, nose or ear. Wash hands afterwards.
- Good questions: "What rule did you use?" "Can you sort them a different way?"
- Expect this: A tiny mustard seed can grow into a plant taller than a rajma plant, so the size of a seed doesn't tell you the size of the plant.
What you need
- Four kinds of dry seeds from the kitchen, such as rajma, chana, moong and mustard (a small handful of each)
- A plate, paper and a pencil
- One rajma bean soaked in water overnight by a grown-up
Child steps
- Notice. Put the seeds on the plate. Look closely and touch them gently. What colours and shapes can you see?
- Guess. Which seed is the biggest? Which is the smallest? Which feels the smoothest?
- Try. Sort the seeds into groups by size. Mix them up and sort them again by colour. Then close your eyes: can you tell which seed is which just by feeling it?
- Observe. Draw each group and count the seeds in it.
- Explain. Tell someone your sorting rule. Why did this seed go into this group?
- Ask another question. What is inside a seed? Look at the soaked rajma bean next to a dry one. Gently peel off its skin with your fingers. What do you see?
हिंदी में समझें
1. ध्यान से देखो – बीजों को थाली में रखो। ध्यान से देखो और धीरे से छूकर देखो। कौन-कौन से रंग और आकार दिखते हैं?
2. अंदाज़ा लगाओ – सबसे बड़ा बीज कौन-सा है? सबसे छोटा कौन-सा है? सबसे चिकना कौन-सा लगता है?
3. करके देखो – बीजों को आकार के हिसाब से समूहों में बाँटो। फिर मिलाकर रंग के हिसाब से बाँटो। अब आँखें बंद करो: क्या तुम सिर्फ़ छूकर बता सकते हो कि कौन-सा बीज कौन-सा है?
4. देखो और लिखो – हर समूह का चित्र बनाओ और उसके बीज गिनो।
5. समझाओ – किसी को अपना बाँटने का नियम बताओ। यह बीज इस समूह में क्यों गया?
6. एक और सवाल पूछो – बीज के अंदर क्या होता है? भिगोए हुए राजमा को सूखे राजमा के पास रखकर देखो। उँगलियों से उसका छिलका धीरे से उतारो। तुम्हें क्या दिखता है?
सुरक्षा: बीज सिर्फ़ देखने और छूने के लिए हैं, खाने के लिए नहीं। छोटे बीज मुँह, नाक या कान में न डालें। बाद में हाथ धोएँ।
Check yourself
Five questions about this rung. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
See the answer and why
- A. A mango seed from inside the fruit Not this one. A mango seed is very big: it goes into the "big" group.
- B. A rajma bean, which is shaped like a kidney Not this one. Rajma beans are big and shaped like a kidney, so they go into the "big" group.
- C. A mustard seed Correct. Mustard seeds are tiny and round, much smaller than the others.
- D. A chana Not this one. A chana is much bigger than a mustard seed.
हिंदी में समझें
A: आम की गुठली बहुत बड़ी होती है, वह "बड़े" समूह में जाती है। B: राजमा बड़ा होता है और गुर्दे जैसा दिखता है, इसलिए वह "बड़े" समूह में जाता है। C: सरसों के बीज बहुत छोटे और गोल होते हैं, बाकी सबसे बहुत छोटे। D: चना सरसों के बीज से बहुत बड़ा होता है।
See the answer and why
- A. Shape (round or flat) Not this one. Round and flat seeds can be the same colour, so shape isn't his rule.
- B. Taste Not this one. We never taste our test seeds, and taste isn't how he sorted them.
- C. Size (big or small) Not this one. He didn't look at big or small. A big seed and a small seed can both be green.
- D. Colour Correct. Green or brown is a colour, so he is sorting by colour.
हिंदी में समझें
A: गोल और चपटे बीज एक ही रंग के हो सकते हैं, इसलिए आकृति उसका नियम नहीं है। B: हम अपने बीज कभी नहीं चखते, और उसने स्वाद से नहीं बाँटा। C: उसने बड़ा-छोटा नहीं देखा। बड़ा और छोटा, दोनों बीज हरे हो सकते हैं। D: हरा और भूरा रंग हैं, इसलिए वह रंग से बाँट रहा है।
See the answer and why
- A. Give the tiny seeds to a baby to play with Not this one. Babies put things in their mouths, and small seeds can make them choke.
- B. Look, touch gently, then wash your hands Correct. Looking and touching are safe, and washing hands is a good habit.
- C. Put one up your nose to smell it Not this one. A seed can get stuck in your nose. Smell with the seed near your nose, held by a grown-up, never inside it.
- D. Taste one raw rajma bean Not this one. Raw rajma is harmful if eaten raw. Seeds are for looking at, not eating.
हिंदी में समझें
A: छोटे बच्चे चीज़ें मुँह में डालते हैं, और छोटे बीज गले में अटक सकते हैं। B: देखना और छूना सुरक्षित है, और हाथ धोना अच्छी आदत है। C: बीज नाक में फँस सकता है। उसे कभी नाक के अंदर मत डालो। D: कच्चा राजमा खाने से नुकसान होता है। बीज देखने के लिए हैं, खाने के लिए नहीं।
See the answer and why
- A. It turned into a plant overnight Not this one. A seed needs days to sprout and grow. One night is not enough to make a plant.
- B. Nothing changed Not this one. Put a soaked bean next to a dry one: you will see it has changed.
- C. It got bigger and softer Correct. A soaked seed swells with water. Its skin becomes soft and easy to peel.
- D. It got smaller and harder, like a tiny pebble Not this one. Soaking doesn't shrink a seed. It takes water in, so it gets bigger.
हिंदी में समझें
A: बीज को उगने में कई दिन लगते हैं। एक रात काफ़ी नहीं है। B: भीगे राजमा को सूखे राजमा के पास रखकर देखो: तुम्हें फ़र्क़ दिखेगा। C: भीगा बीज पानी सोखकर फूल जाता है और उसका छिलका नरम होकर आसानी से उतरता है। D: भिगोने से बीज छोटा नहीं होता। वह पानी सोखकर बड़ा होता है।
See the answer and why
- A. Small seeds never grow Not this one. Small seeds grow too. Mustard plants grow from tiny seeds.
- B. A big seed always makes a big plant, and a small seed a small one Not this one. Not always. The mustard plant grows from a tiny seed and can grow taller than the rajma plant.
- C. Both plants will be the same size Not this one. Different plants grow to different sizes, whatever their seeds look like.
- D. Seed size doesn't tell you plant size Correct. A tiny mustard seed can grow into a plant taller than a rajma plant.
हिंदी में समझें
A: छोटे बीज भी उगते हैं। सरसों के पौधे छोटे बीजों से ही उगते हैं। B: हमेशा नहीं। सरसों छोटे बीज से उगती है और राजमा के पौधे से ऊँची हो सकती है। C: अलग-अलग पौधे अलग-अलग नाप के होते हैं, बीज चाहे जैसे दिखें। D: सरसों का छोटा-सा बीज राजमा के पौधे से भी ऊँचा पौधा बन सकता है।
For teachers
- Learning aims: Notice properties (size, colour, shape, texture); sort by a rule and explain the rule; see that a seed has parts inside.
- Subject links: Maths: counting, grouping and simple patterns (big, small, small). Language: describing words (smooth, wrinkly, round, flat). Art: a seed picture glued onto card.
- Key vocabulary: seed, skin (seed coat), sort, group, rule, smooth, wrinkly.
- Review: Can the child say the rule they used, and sort again by a different rule?
Rung 2 · Classes 4–7
Do Seeds Need Light to Sprout?
Before you start: safety and help
For the grown-up or teacher who helps. Students: read it too, so you know the rules.
- Safety: Don't eat the test sprouts: they have been sitting out for days. Throw away any seeds that grow mould, and wash hands after handling them.
- Safety: Put the cups where they can't be knocked over, and wipe up spills.
- Good questions: "Seeds under the soil start in the dark. Why might it help a seedling to grow up fast before it reaches the light?"
- Expect this: Seeds sprout in both cups, usually within a day or two, because a seed carries its own food. In the dark, the sprouts often grow taller, thinner and pale yellow: they are stretching to find light. In the light they stay shorter, sturdier and turn green. That is a good result, not a failed one.
What you need
- 20 moong seeds, soaked in water for a few hours
- 2 small plastic cups or steel katoris, with cotton wool or tissue paper
- Water, a dark cupboard and a bright windowsill (not in hot, direct sun)
- A ruler with millimetres, paper and a pencil
Student steps
- Notice. A seed under the soil starts to grow in the dark. Look at a dry moong seed and one that was soaked for a few hours. What has changed?
- Guess. Put damp cotton in both cups and 10 soaked seeds in each. One cup goes into a dark cupboard, the other onto a bright windowsill. Which cup will sprout first? Which sprouts will be taller after five days? Write your guesses and your reasons.
- Try. Keep everything the same except the light: the same kind of seeds, the same cups, the same amount of water, the same room. Each morning, check that the cotton is damp but not flooded.
- Observe. Each morning for five to seven days, count how many seeds have sprouted in each cup, measure the three tallest sprouts in millimetres, and note their colour. Record it all in a table.
- Explain. Use your table. What did light change, and what did it not change? Show someone where the biggest difference between the cups appears.
- Ask another question. Move the pale sprouts into the light for two days. What happens to their colour? Would the amount of water change how fast the roots grow?
Check yourself
Five questions about this rung. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
See the answer and why
- A. Seeds don't need water Not this one. Both cups had damp cotton. This test changed the light, not the water.
- B. The dark seeds were broken Not this one. They sprouted, so they weren't broken.
- C. Light makes seeds sprout faster every time Not this one. Both cups sprouted. One test doesn't show "every time", and light wasn't needed to start.
- D. Seeds don't need light to start sprouting Correct. A seed carries its own food, so it can start growing in the dark. Light is needed later.
See the answer and why
- A. So the cups look the same in photos Not this one. How they look isn't the reason. Fairness is.
- B. Because water makes the sprouts green Not this one. Light, not water, is what lets seedlings turn green.
- C. So that light is the only thing that changes Correct. That is a fair test: change one thing, keep the rest the same.
- D. Because seeds kept in a dark cupboard use up more water than seeds in light Not this one. A cupboard doesn't use water. The same water keeps the test fair.
See the answer and why
- A. They are stretching up to find light Correct. Without light, a seedling grows tall and pale, searching for light.
- B. Someone pulled them Not this one. Nothing in the test pulled them. Being in the dark explains it.
- C. Darkness is better for plants Not this one. The dark sprouts are weak and pale. They need light to make food and stay healthy.
- D. They are a different kind of seed that always grows tall and pale Not this one. Both cups had the same kind of moong seed.
See the answer and why
- A. 60 mm Not this one. That is the tallest one, not the mean.
- B. 50 mm Correct. Add them (40 + 50 + 60 = 150), then divide by 3: 150 ÷ 3 = 50 mm.
- C. 150 mm Not this one. That is the total. Divide it by the number of sprouts (3) to find the mean.
- D. 45 mm Not this one. Check the adding: 40 + 50 + 60 = 150, and 150 ÷ 3 = 50.
See the answer and why
- A. The seed numbers differ, so it isn't fair Correct. With 2 seeds, one dud seed changes the result a lot. Use the same number in each cup.
- B. Nothing: any number of seeds is fine Not this one. A fair test keeps everything the same except the light, and that includes the number of seeds.
- C. The dark cup should get more water Not this one. Changing the water too would add a second difference.
- D. He should have used fewer seeds in the light cup Not this one. Both cups need the same number, not fewer in one of them.
For teachers
- Learning aims: Run a fair test that changes one thing (light); measure in millimetres; record over several days; let evidence correct a guess.
- Subject links: Maths: a table and a line graph of height over days, and the mean of the three tallest sprouts. Computing and logic: a flowchart on paper: "If sprouted, measure it; if not, check the cotton is damp." Language: a short daily observation diary.
- Key vocabulary: germinate, sprout, fair test, variable, millimetre, pale (etiolated) seedling.
- Note: This rung goes deeper than rung 2.1 ("What Does a Seed Need?", Classes 1–3) by measuring and graphing.
- Review: Did the student change only the light? Do their conclusions come from their own table?
Rung 3 · Classes 8–10
The Farmer's Seed Choice
Before you start: safety and help
For the grown-up or teacher who helps. Students: read it too, so you know the rules.
- This is a paper exercise with made-up but realistic numbers; real prices change every season.
- Good questions: "When an advert shows a big number, what question should we ask about it?"
- If your family or neighbours farm, talk about how they choose seed, but keep it to what they are happy to share.
What you need
- Paper, a pencil and a calculator if you have one
- A seed packet or a seed advertisement, if you can find one
- The example card. It is made up but realistic, for one acre of wheat. Seed A (the farmer's usual seed): ₹40 per kg, 40 kg needed (₹1,600), about 12 quintals of grain in a normal year and about 10.2 quintals in a dry year. Seed B (a newer variety): ₹90 per kg, 40 kg needed (₹3,600), about 15 quintals in a normal year and about 10.5 quintals in a dry year. Other costs (fertiliser, water, labour) are ₹15,000 for either seed. The grain sells for ₹2,400 per quintal.
Student steps
- Notice. Look at a seed packet or advertisement, or the example card. What does it promise? Find the numbers: price, germination percentage and expected harvest. What does "95% germination" mean? (In a test, 95 out of every 100 seeds sprouted.)
- Guess. Which seed should a small family farm buy: A, the cheaper one, or B, the dearer one with a bigger harvest in a normal year? Write your guess and your reason.
- Try. For each seed, work out cost, income and profit for a normal year and for a dry year. Write it as an equation: profit = harvest × price − (seed cost + other costs).
- Observe. Which seed earns more in a normal year? In a dry year? How many extra quintals must Seed B give just to pay back its extra seed cost (the break-even point)?
- Explain. Write a short evidence brief: which seed would you advise for a family farm that often faces dry years? Use your numbers, and say what fact would change your mind.
- Ask another question. What do the numbers leave out? Think about loans, risk, saving seed for next year, and what the family needs to eat.
Check yourself
Five questions about this rung. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
See the answer and why
- A. The harvest will be 95% bigger Not this one. Germination is about seeds sprouting, not about how much grain the plants give.
- B. 95% of farmers liked the seed Not this one. The number is about seeds that sprouted, not about anyone's opinion.
- C. The seed will grow well in 95% of all kinds of weather Not this one. The test is done in set conditions. It can't promise anything about the weather.
- D. About 95 in 100 seeds sprouted in a test Correct. Germination means sprouting. It says nothing directly about the size of the harvest.
See the answer and why
- A. ₹28,800 (the money from selling the grain) Not this one. That is the income. Take away the costs to find the profit.
- B. ₹13,800 (after the ₹15,000 of other costs) Not this one. That left out the seed cost. Costs are ₹1,600 + ₹15,000 = ₹16,600.
- C. ₹12,200 Correct. Income 12 × ₹2,400 = ₹28,800. Costs ₹1,600 + ₹15,000 = ₹16,600. Profit ₹28,800 − ₹16,600 = ₹12,200.
- D. ₹17,400 Not this one. That is Seed B's profit in a normal year, not Seed A's.
See the answer and why
- A. Neither, because both make a loss Not this one. Both still make a profit on the card's numbers, just smaller than in a normal year.
- B. Seed A, ₹7,880 against ₹6,600 Correct. A: 10.2 × ₹2,400 = ₹24,480 − ₹16,600 = ₹7,880. B: 10.5 × ₹2,400 = ₹25,200 − ₹18,600 = ₹6,600.
- C. They earn exactly the same Not this one. Work it out: ₹7,880 for A and ₹6,600 for B.
- D. Seed B, because it always gives more grain Not this one. B gives a little more grain (10.5 against 10.2 quintals), but its higher seed cost wipes out the gain.
See the answer and why
- A. 2,000 kg Not this one. That treats rupees as kilograms. Divide the extra cost by the price per quintal.
- B. 3 quintals Not this one. That is the extra grain in a normal year (15 − 12), not the break-even amount.
- C. 1.2 quintals (2,400 ÷ 2,000) Not this one. That is the price ratio turned upside down (2,400 ÷ 2,000). Divide the cost by the price.
- D. About 0.84 quintal Correct. ₹2,000 ÷ ₹2,400 ≈ 0.83, so a little more than 0.83 quintal is needed to break even.
See the answer and why
- A. "A earns more in dry years, B in normal ones; with frequent dry years, choose A." Correct. It uses the calculations, names the risk and gives clear advice for this farm.
- B. "Seed A, because new things are always worse." Not this one. That's a feeling, not evidence, and in a normal year B does earn more.
- C. "It doesn't matter, because farming is luck." Not this one. Weather is uncertain, but the numbers still show which choice carries less risk.
- D. "Seed B, because the advert says it is the best seed for every Indian farmer." Not this one. An advert is a claim, not evidence. The calculations say more.
For teachers
- Learning aims: Build and compare linear expressions; find a break-even point; read a product claim critically; argue from evidence.
- Key numbers: Normal year: A earns ₹28,800 and costs ₹16,600, profit ₹12,200; B earns ₹36,000 and costs ₹18,600, profit ₹17,400. Dry year: A ₹24,480 − ₹16,600 = ₹7,880; B ₹25,200 − ₹18,600 = ₹6,600. Break-even: B's extra seed cost is ₹2,000, and ₹2,000 ÷ ₹2,400 ≈ 0.83, so B must give at least about 0.84 quintal (84 kg) more grain than A.
- Logic: "95% germination" is about seeds sprouting in a test, not about the size of the harvest. A claim can be true and still not answer your question.
- Subject links: Maths: linear equations, percentages and break-even (the Class 10 Lab activity "The first profitable ticket"). Social science: farm costs, risk and food security. Language: writing a short evidence brief.
- Review: Is the recommendation built on the student's own calculations, and does it name the risk of a dry year?
Rung 4 · Classes 11–12
Who Keeps the Seed? Diversity, Hybrids and Farmers' Rights
Before you start: safety and help
For the grown-up or teacher who helps. Students: read it too, so you know the rules.
- Privacy: If students interview farmers or seed sellers, they ask first, explain the purpose, record no names, and anyone can stop at any time.
What you need
- A library, or trusted websites (government departments, universities, the UN's Food and Agriculture Organization)
- A notebook for a research outline
Student steps
- Notice. For thousands of years, farmers saved and swapped their own seed. Today many buy new seed every season. Find out why: what happens when a farmer saves and replants seed from a hybrid crop?
- Guess / Hypothesise. Choose one focused question, such as: "Does growing several varieties of a crop make a farm more able to cope with drought or pests than growing one variety?" Write a hypothesis you could test with evidence.
- Try. Draft a short research proposal: your question, what evidence would answer it (for example, published yield records, seed bank reports, government data), and how you would find it. Include at least one source that disagrees with your hypothesis.
- Observe. Judge each source: who produced it, who paid for it, what was measured, how large the sample was, and what was left out.
- Explain. Write a structured outline: question, hypothesis, evidence for, evidence against, conclusion, limits of your evidence, and a bibliography.
- Ask another question. Who should own a new plant variety: the breeder who developed it, the farmers whose traditional varieties it came from, or both? Find out how India's Protection of Plant Varieties and Farmers' Rights Act, 2001 tries to balance them.
Check yourself
Five questions about this rung. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
See the answer and why
- A. Hybrid plants make no seeds at all Not this one. Most hybrid crops do produce seed. It just doesn't grow true to type.
- B. Saved hybrid seed gives uneven, often smaller crops Correct. Hybrids don't breed true, so the next generation is mixed.
- C. Hybrid seeds are made so that they can never sprout a second time Not this one. Saved hybrid seed can sprout. The problem is that the plants vary.
- D. It is against the law in India to save any seed Not this one. Indian law protects farmers' right to save and re-sow seed.
See the answer and why
- A. Save, re-sow, swap and sell their seed, but not as branded seed Correct. The Act balances breeders' rights with farmers' traditional rights.
- B. Sell any variety under the original company's brand name Not this one. Selling it as branded seed of a protected variety is not allowed.
- C. Nothing: all seed belongs to the companies Not this one. The Act names farmers' rights alongside breeders' rights.
- D. Only grow seed bought from the government or from a licensed company shop Not this one. The Act doesn't limit farmers to government seed.
See the answer and why
- A. If one variety fails, others may survive Correct. Diversity spreads risk, like not keeping all your eggs in one basket.
- B. Several varieties always give a bigger harvest than one, in every kind of year Not this one. Not always. A single high-yield variety can give more in a good year.
- C. Pests can't find mixed fields Not this one. Pests can still find them. The point is that not every variety is equally harmed.
- D. Diversity changes the weather Not this one. Diversity doesn't change the weather. It changes how much a farm loses when the weather is bad.
See the answer and why
- A. Trust it, because companies know their own seed better than anyone else does Not this one. Knowing a product well doesn't remove the reason to present it favourably.
- B. Check its method and look for independent studies Correct. Who paid is a reason to look harder, not proof that it is wrong.
- C. Reject it at once, because it must be false Not this one. Funding is a warning sign, not proof. Judge the evidence itself.
- D. Ignore who paid, because only the numbers matter Not this one. Who paid can shape what was measured and what was left out.
See the answer and why
- A. "Mixed varieties are always better, everywhere in the world and in every season." Not this one. Three villages and one season can't support "always" and "everywhere".
- B. "Nothing can be learned from a small study." Not this one. Small studies can still show a pattern worth testing further.
- C. "Here, this season, mixed fields lost less; test more places." Correct. It states what the evidence shows and admits its limits.
- D. "The evidence proves hybrids are harmful." Not this one. The study didn't test harm from hybrids. Stay within what was measured.
For teachers
- Learning aims: Ask a focused research question; judge sources for method and bias; weigh more than one side; write a structured, referenced outline.
- Key facts: Seed saved from a hybrid crop does not "breed true": the next generation varies and usually yields less, which is one reason farmers buy hybrid seed again. India's 2001 Act lets farmers save, use, sow, re-sow, exchange, share and sell their farm produce, including seed of protected varieties, but not sell it as branded seed of a protected variety. India's national seed collection is kept in the National Gene Bank in New Delhi.
- Balance: Plant breeders and seed companies argue that protection pays for years of research. Farmers' groups argue for the right to save seed and for keeping many local varieties alive. Students should present both and reach their own reasoned view.
- Subject links: Biology: genes, inheritance and variation. Social science: law, farming and food security. Logic: spotting bias, cherry-picked data and loaded words.
- Review: Does the outline weigh evidence on both sides, judge its sources, and keep its conclusion as modest as the evidence?
Same spark, other subjects
A seed
One seed, looked at as a scientist, a mathematician, an economist and a researcher.
- What Does a Seed Need? Biology · Topic ladder, Classes 1–3
- Measure the plant the same way each time Maths · Class 3
Already in the School Lab
These Lab pages practise the same ideas, with questions to check yourself.
- Look closely at a growing plant Class 1 experience
- Measure the plant the same way each time Class 3 experience
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