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Topic ladders · Science

Living Things (Plants Focus)

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.

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

What Does a Seed Need?

Before you start: safety and help

For the grown-up who helps.

  • Safety: Do not eat the experimental seeds. Some raw beans (like rajma) are harmful raw. Keep water amounts small to avoid mess. Wash hands after handling.
  • Time: Daily 5-minute checks for one week.
  • Good questions: "What changed?" "Which one is growing best?"
  • Expect this: Seeds with water usually sprout in the light and in the dark. That is a good result, not a mistake: the seed carries its own food. Seedlings in the dark grow tall, thin and pale yellow, because they need light later to make food.

What you need

  • 12–16 bean, moong or mustard seeds
  • Cotton, tissue or soil
  • 4 small containers or plastic lids
  • Water

Child steps

  1. Notice. Look at a dry seed. What does it look like? Feel like?
  2. Guess. What do you think a seed needs to start growing? (water, light, air, soil?)
  3. Try. Put 3 or 4 seeds in each of four lids: one with wet cotton in the light, one with dry cotton in the light, one with wet cotton in a dark cupboard, one with wet cotton in a closed tin.
  4. Observe. Check every day for 5–7 days. Draw what you see.
  5. Explain. Which seeds started to grow? Were you surprised by the ones in the dark?
  6. Ask another question. What happens to the seedlings in the dark after a few more days? Can we try a different seed?
For teachers
  • Learning aims: Understand that seeds need water (and air, and warmth) to germinate; light is needed later for the young plant to make food. Observe and record.
  • Key vocabulary: seed, grow, germinate, water, light, air.
  • Review: Children show their drawings and say what the seed needed to start, and what the young plant needed next.

Rung 2 · Classes 4–7

How Do Plants Drink?

Before you start: safety and help

For the grown-up or teacher who helps. Students: read it too, so you know the rules.

  • Safety: A grown-up does all cutting with a knife or scissors. Food colouring and ink can stain: use an old cloth or newspaper underneath.
  • Good questions: "Where do you see the colour?" "How do you think it moved?"

What you need

  • A white flower with a stem (tuberose, white chrysanthemum) or a balsam plant, or a celery stalk with leaves
  • Glass of water
  • Food colouring or ink (any dark colour)
  • Optional: second glass with plain water

Student steps

  1. Notice. Look at the stem of a plant or flower. How do you think water reaches the leaves and flowers?
  2. Guess. If we put coloured water in the glass, what will happen to the flower or leaves?
  3. Try. Ask a grown-up to trim the bottom of the stem. Stand the stem in coloured water. Leave it for a few hours or overnight.
  4. Observe. Look at the petals and leaves. Ask a grown-up to cut across the stem. What do you see?
  5. Explain. How did the colour travel? What does this tell us about how plants take in water?
  6. Ask another question. Does it work faster in warm or cool water? What if we use a different plant? (Change only one thing at a time.)
For teachers
  • Learning aims: Understand that water travels up the stem through thin tubes (xylem); observe transport in plants.
  • Key vocabulary: stem, roots, transport, tubes, absorb.
  • Note: The cut stem shows coloured dots or lines: these are the tubes. Water is pulled up partly because it evaporates from the leaves (transpiration).
  • Review: Students draw the path the coloured water took and explain it.

Rung 3 · Classes 8–10

Testing What Affects Photosynthesis

Before you start: safety and help

For the grown-up or teacher who helps. Students: read it too, so you know the rules.

  • Plants are living things: bring the dark plant back into the light afterwards and watch it recover.
  • Help with accurate, dated recording.
  • Not at home: The starch (iodine) test on leaves uses boiling alcohol, which catches fire easily. It is a school-laboratory demonstration with a teacher only.

What you need

  • Two (or better, four) similar potted plants of the same kind and size
  • One dark cupboard or a large box
  • Water, notebook, ruler

Student steps

  1. Notice. Plants make their own food using light. What conditions do you think they need for this?
  2. Guess. What will happen to a plant left in the dark for a week compared with one in light?
  3. Try. Keep half the plants in normal light and half in complete darkness for 7 days. Water both equally and keep them at the same temperature. This is a fair test: only light is different.
  4. Observe. Every day, record leaf colour, new growth, stem length and whether leaves droop. Take a photo or draw if you can.
  5. Explain. Why did the changes happen? Does your evidence show that the plant could not make food, or only that it looked different? Write what you can and cannot say from your results.
  6. Ask another question. How could we test the effect of carbon dioxide or water more carefully?
For teachers
  • Learning aims: Link light to photosynthesis; design a simple fair test; record qualitative data; draw a conclusion that matches the evidence.
  • Key vocabulary: photosynthesis, chlorophyll, light, fair test, variable, control.
  • Note: A week of darkness gives pale new growth and some yellowing, which supports the idea that light is needed, but does not on its own prove that food-making stopped. A teacher may follow up with the destarched-leaf iodine test as a laboratory demonstration.
  • Review: Students write a short conclusion based only on their evidence, plus one limitation.

Rung 4 · Classes 11–12

Designing a Plant Investigation

Before you start: safety and help

For the grown-up or teacher who helps. Students: read it too, so you know the rules.

  • Safety and ethics: No weedkillers, strong fertilisers or other harmful chemicals without a teacher. Do not take plants from parks, forests or protected places, and ask before working in someone's garden or field.

What you need

  • Materials depend on the student's chosen question (seeds, pots, rulers, light source, etc.)
  • Lab notebook or paper

Student steps

  1. Notice. Observe plants in different conditions around you (shade vs sun, different soils, crowded vs spaced).
  2. Guess / Hypothesise. Write a clear, testable question and your predicted outcome.
  3. Try. Design and carry out a controlled investigation (identify independent, dependent and controlled variables; use several plants per condition).
  4. Observe. Collect quantitative data over time. Use tables and graphs.
  5. Explain. Analyse results, discuss limitations, and relate findings to plant physiology (photosynthesis, transpiration, growth regulators, etc.).
  6. Ask another question. What would be the next logical investigation? How could the method be improved?
For teachers
  • Learning aims: Plan and evaluate a scientific investigation; collect and interpret data; communicate findings clearly.
  • Support students in choosing realistic, ethical investigations and in discussing experimental error and reliability.

Same spark, other subjects

A seed

One seed, looked at as a scientist, a mathematician, an economist and a researcher.

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