Year 3 Science · What plants need · Lesson 3.3

Year 3 Science: Water and nutrients from the soil

Part of the Year 3 Science what plants need chapter. Chapter overview · whole chapter on one page

3.3

Water and nutrients from the soil

Year 3
Explore the requirements of plants for life and growth: water and nutrients from the soil, taken in by the roots

Story. Amira’s bean plant has pale leaves. Its pot has old soil that has been used for many years. Her teacher says, “Plants take nutrients from the soil. After a long time, the soil may not have enough left.”

The roots take in water from the soil. The water carries nutrients into the roots with it. Nutrients help the plant to grow well. Two examples of nutrients are nitrogen and phosphorus.

Nutrients are not food. A plant makes its food in its leaves, using light, water and carbon dioxide. The nutrients from the soil help the plant to build the parts it needs to grow.

Roots also need some air in the soil. The spaces between the soil crumbs hold air. Soil that is always soggy has little air in it, and this can harm the roots.

Soil holds water, nutrients, small stones and bits of old plants. The roots take in water and nutrients.

Key ideas

Roots take in water and nutrients from the soil.
Nutrients are substances in the soil that a plant needs to grow well.
Nutrients are not food. Leaves make food from light, water and carbon dioxide.
Soggy soil with very little air can harm the roots.

Worked example 3.3.1

Where do the roots take nutrients from? Write the place.

Method. Think about where the roots are.

Think about the roots. The roots are in the soil, and they take in water and nutrients.
roots in soil
Think about the nutrients. The nutrients come from the soil, and the roots take them in.
from the soil
Name the place. The roots take nutrients from the soil.
soil
Write the answer.
soil

Check. The soil holds the nutrients that the roots take in. ✓

Worked example 3.3.2

Amira’s plant has pale leaves in old soil. Which need might be short? Write the need.

Method. Think about what the old soil may have less of.

Read the story. The soil is old, and it has been used for a long time.
old soil
Think about the soil. Plants use up the nutrients in the soil over time.
nutrients used up
Name the need. The need that may be short is nutrients from the soil.
nutrients from soil
Write the answer.
nutrients from soil

Check. Pale leaves can show that a plant is short of nutrients. ✓

Watch out. The leaves are not short of light here. The soil is the place where the need is short.

Worked example 3.3.3

Maya says nutrients are the food that a plant eats. Is she right? Write no, and say what the leaves make food from.

Method. Check what nutrients are and what food is.

Read the claim. Maya says nutrients are a plant’s food.
claim
Check the facts. Nutrients are substances the plant takes in from the soil to grow well. They are not food.
not food
Name what the leaves use. Leaves make food from light, water and carbon dioxide.
light, water, carbon dioxide
Write the answer.
No. Accept any answer that says the leaves make food from light, water and carbon dioxide, and nutrients are not food.

Check. A plant makes its own food in its leaves. ✓

Watch out

Watch out: do not say that roots take in light. Roots take in water and nutrients from the soil. Light is used by the leaves.

Try it at home or school (with a grown-up). Put a spoonful of garden soil onto a plate or tray, with a grown-up. Look at it with a magnifying glass. Can you find small stones, dark bits of old leaves, and crumbs of soil? Do not eat or taste the soil. Wash your hands well afterwards.

Exam tip

Grown-up tip. Ask: “What is in the soil? What do the roots take out of it?” Let your child point to a stone and to a bit of old leaf, and say which of these could be a nutrient.