Chapter 5 of 8

All 8 chapters
  1. 1Plant parts and their jobs, readunderstood
  2. 2From seed to seedling, readunderstood
  3. 3A fair test with plants, readunderstood
  4. 4Light, water and plant health, readunderstood
  5. 5Leaves make food, readunderstood
  6. 6Flowers and pollination, readunderstood
  7. 7How seeds travel, readunderstood
  8. 8The life cycle of a plant, readunderstood

S2.1.5 Chapter 5

Leaves make food

How does a plant get its food?

Your guess

Pick one before you read on. It is fine to be wrong.

Your guess

  • You picked A. Read on. At the end, the chapter comes back to your guess.

  • You picked B. Read on. At the end, the chapter comes back to your guess.

  • You picked C. Read on. At the end, the chapter comes back to your guess.

By the end you can

  • Explain that green leaves use sunlight, air and water to make food
  • Explain why animals depend on plants for food

You eat food to grow and to move. A plant needs food too. A plant has no mouth. So how does it get food?

A green plant makes its own food. It makes the food in its green leaves.

A leaf needs three things. The first is sunlight. The second is water. The third is a gas from the air.

The roots take in water from the soil. The water goes up the stem to the leaf.

Draw it first

Draw what a leaf needs

  1. A young plant in soil. The Sun, labelled sunlight, sends two arrows to the leaves. An arrow from the left points at the roots, labelled water. Two arrows from the right point at the leaves, labelled gas from air. A word on the left, labelled sugar, points at a leaf. An arrow leaves the plant to the right, labelled oxygen.sunlight

    1 Draw a plant. Draw the Sun and arrows to the leaves. Write sunlight.

  2. A young plant in soil. The Sun, labelled sunlight, sends two arrows to the leaves. An arrow from the left points at the roots, labelled water. Two arrows from the right point at the leaves, labelled gas from air. A word on the left, labelled sugar, points at a leaf. An arrow leaves the plant to the right, labelled oxygen.sunlightwater

    2 Draw an arrow to the roots. Write water.

  3. A young plant in soil. The Sun, labelled sunlight, sends two arrows to the leaves. An arrow from the left points at the roots, labelled water. Two arrows from the right point at the leaves, labelled gas from air. A word on the left, labelled sugar, points at a leaf. An arrow leaves the plant to the right, labelled oxygen.sunlightwatergas from air

    3 Draw arrows from the air to the leaves. Write gas from air.

  4. A young plant in soil. The Sun, labelled sunlight, sends two arrows to the leaves. An arrow from the left points at the roots, labelled water. Two arrows from the right point at the leaves, labelled gas from air. A word on the left, labelled sugar, points at a leaf. An arrow leaves the plant to the right, labelled oxygen.sunlightwatergas from airsugaroxygen

    4 Write sugar by a leaf. Draw an arrow out. Write oxygen.

The leaf uses the three things to make sugar. Sugar is the food of the plant. The plant uses it to grow.

The leaf also gives out oxygen. Oxygen is a gas in the air. People and animals need it to breathe.

The gas the leaf takes in is a different gas. It is called carbon dioxide. A leaf does not take in oxygen to make food.

A big leaf on a stalk. Four arrows. An arrow from the Sun, labelled sunlight, points at the leaf. An arrow labelled water goes up along the stalk. An arrow from the right, labelled gas from air, points at the leaf. An arrow leaves the leaf towards the lower right, labelled oxygen out. Labels: sunlight, gas from air, oxygen out, water.sunlightgas from airoxygen outwater
Three things go in. Oxygen comes out.

See it three ways

As a picture

Three boxes at the top, labelled sunlight, water and gas. An arrow points down, labelled in the leaf. Two boxes below the arrow are labelled sugar and oxygen.sunlightwatergasin the leafsugaroxygen

In words

Sunlight, water and a gas from the air go into the leaf. Sugar and oxygen come out.

Soil does not feed a plant. It holds the plant up. It gives water. It also gives small amounts of minerals.

Minerals are like vitamins for people. They help a plant stay well. They are not its food.

A young plant in soil, labelled soil. Each part is joined to its job by a line. The leaf is labelled makes food. The stem is labelled water up. The root is labelled water in. Labels: makes food, water up, water in, soil.makes foodwater upwater insoil
The soil gives water, not food. The leaf makes the food.

Animals cannot make their own food. They eat plants. Or they eat animals that ate plants.

A food chain shows who eats what. The arrows point to the eater.

A food chain of three boxes joined by arrows. The boxes are labelled grass, zebra and lion. Each arrow points to the animal that eats.grasszebralion
The food starts with the grass.

A lion eats only meat. But the zebra it eats ate grass. So the lion's food starts with a plant too.

Try it

What happens to grass with no light?

You need: a small patch of grass in the light, a flat board or a flat stone, a week.

Be safe: Let a grown up lift the board or stone. Snakes, scorpions, spiders and stinging insects can hide under it. Wash your hands after touching soil or plants.

  1. Pick a small patch of grass in the light. Look at its colour.
  2. Cover the patch with the flat board or stone.
  3. Leave it for a week.
  4. Ask a grown up to lift the board. Look at the grass under it. Look at the grass beside it.
  5. Leave the board off. Look again after a few days.

What you will see: The grass under the board is pale yellow. The grass in the light is green. With no light, the grass cannot make food. After a few days in the light, it slowly turns green again.

If you cannot try it, this is what happens.
Two patches of grass on a ground line. The left patch has pale, dashed blades, labelled pale yellow and under a board. The right patch has solid blades, labelled green and in the light.pale yellowunder a boardgreenin the light

A wrong idea many people have

A plant gets its food from the soil.

Why it feels right: Roots go into the soil. A plant grows in soil. So the soil must be its food.

The test that breaks it: Long ago a man grew a willow tree in a tub. The tub held soil, and he weighed the soil first. He gave the tree only rain water. After five years the tree had gained about 75 kg. The soil had lost less than 100 g. At home, cover grass with a board for a week. It still has soil and water. With no light it goes pale.

What is true: A plant makes its food in its leaves. It uses sunlight, water and a gas from the air. Soil gives water and minerals, not food.

Key words

sugar
the food a green leaf makes.
oxygen
a gas in the air. A leaf gives it out. We breathe it.
minerals
tiny bits in soil that help a plant stay well. Not its food.
food chain
a line that shows who eats what. The arrows point to the eater.

Back to your guess

The answer is A: It makes its food in its leaves.

A plant makes its own food in its green leaves. It uses sunlight, water and a gas from the air.

Check yourself

Try each one before you look. A wrong answer tells you where to go next.

  1. What does a green leaf use to make food?

    Tap your answer.

    1. Not this one. Soil is not the plant's food. A leaf needs light, water and a gas. Try another.

    2. Not this one. Water is one of three things. A leaf needs light and a gas from the air too. Try another.

    3. Not this one. Sunlight is one of three things. A leaf needs water and a gas from the air too. Try another.

    4. Yes, that is right. The leaf uses these three things to make sugar. Sugar is the plant's food.

    See the answer

    Sunlight, water and a gas from the air

    The leaf uses these three things to make sugar. Sugar is the plant's food.

    • If you chose A: Soil is not the plant's food. A leaf needs light, water and a gas.
    • If you chose B: Water is one of three things. A leaf needs light and a gas from the air too.
    • If you chose C: Sunlight is one of three things. A leaf needs water and a gas from the air too.

  2. Where does a plant make most of its food?

    Tap your answer.

    1. Not this one. Roots take in water from the soil. The leaves make the food. Go to S2.1.1. Try another.

    2. Yes, that is right. Green leaves catch light. They make sugar from light, water and a gas from the air.

    3. Not this one. The soil does not make food. Soil gives water and minerals. Try another.

    See the answer

    In its leaves

    Green leaves catch light. They make sugar from light, water and a gas from the air.

    • If you chose A: Roots take in water from the soil. The leaves make the food. Go to S2.1.1.
    • If you chose C: The soil does not make food. Soil gives water and minerals.

  3. Kofi covers a patch of grass with a board for a week. What does he see when he lifts it?

    Tap your answer.

    1. Yes, that is right. With no light, the leaves cannot make food. The grass turns pale. It turns green again in the light.

    2. Not this one. Under the board there is no light. The grass goes pale. It cannot make food. Try another.

    3. Not this one. Without light the grass cannot make food to grow. It goes pale. Try another.

    See the answer

    Pale yellow grass

    With no light, the leaves cannot make food. The grass turns pale. It turns green again in the light.

    • If you chose B: Under the board there is no light. The grass goes pale. It cannot make food.
    • If you chose C: Without light the grass cannot make food to grow. It goes pale.

  4. A lion eats only meat. Does it depend on plants?

    Tap your answer.

    1. Not this one. The lion eats animals that ate plants. Its food still starts with a plant. Try another.

    2. Not this one. The lion does not need to eat grass. The zebra ate it. So the lion's food starts with a plant. Try another.

    3. Yes, that is right. The lion's food starts with grass, through the zebra. On land, meat eaters depend on plants too.

    See the answer

    Yes. The animals it eats ate plants.

    The lion's food starts with grass, through the zebra. On land, meat eaters depend on plants too.

    • If you chose A: The lion eats animals that ate plants. Its food still starts with a plant.
    • If you chose B: The lion does not need to eat grass. The zebra ate it. So the lion's food starts with a plant.

  5. From an earlier chapter

    Which part of a plant takes in water from the soil?

    Tap your answer.

    1. Not this one. Leaves make food. Roots take in water from the soil. Go to S2.1.1. Try another.

    2. Yes, that is right. Roots take in water and send it up the stem.

    3. Not this one. The flower makes seeds. Roots take in water from the soil. Go to S2.1.1. Try another.

    See the answer

    The roots

    Roots take in water and send it up the stem.

    • If you chose A: Leaves make food. Roots take in water from the soil. Go to S2.1.1.
    • If you chose C: The flower makes seeds. Roots take in water from the soil. Go to S2.1.1.

  6. Draw a leaf making food. Show what goes in and what comes out.

    See the answer

    Arrows in: sunlight, water and a gas from the air. Arrows out: sugar, the food, and oxygen.

    A leaf uses three things to make sugar. It gives out oxygen.

  7. Look at the picture. Which letter shows oxygen leaving the leaf?

    A big leaf on a stalk with four arrows, marked A, B, C and D. Labels: A, B, C, D.ABCD
    Tap your answer.

    1. Not this one. A is sunlight, and it goes into the leaf. Oxygen is a gas that leaves. Try another.

    2. Not this one. B points into the leaf. It shows the gas from the air going in, not oxygen. Try another.

    3. Yes, that is right. C is an arrow leaving the leaf. A leaf gives out oxygen.

    4. Not this one. D is water. It comes up the stalk from the roots, into the leaf. The arrow points in, not out. Try another.

    See the answer

    C

    C is an arrow leaving the leaf. A leaf gives out oxygen.

    • If you chose A: A is sunlight, and it goes into the leaf. Oxygen is a gas that leaves.
    • If you chose B: B points into the leaf. It shows the gas from the air going in, not oxygen.
    • If you chose D: D is water. It comes up the stalk from the roots, into the leaf. The arrow points in, not out.

Keep it

Copy this into your exercise book.

Leaves use sunlight, water and a gas from air to make sugar. Sugar is the plant's food. Leaves give out oxygen. Soil gives water, not food. Animals eat plants, or animals that ate plants.

Draw: A leaf. Arrows in: sunlight, water, gas. Arrows out: sugar, oxygen.

Reading with a child? A short page for the adult: what this chapter teaches and three questions to ask.

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