Year 3 Science: Room to grow, and how plants differ
Part of the Year 3 Science what plants need chapter. Chapter overview · whole chapter on one page
Room to grow, and how plants differ
Room to grow means space for the roots to spread out in the soil, and space for the leaves to spread out in the light. When plants are crowded, they must share the light, the water and the nutrients. A crowded plant may grow less well.
Plants do not all need the same amount of each thing. They vary from plant to plant:
- a cactus lives where there is very little rain, so it needs little water. Its thick stem can store water;
- a water lily lives in a pond, with its leaves floating on the water;
- a sunflower grows tall, and it needs lots of light.
Key ideas
- Room to grow means space for the roots and the leaves.
- Crowded plants share the light, water and nutrients.
- A cactus needs little water. A water lily lives in water. A sunflower needs lots of light.
- Plants do not all need exactly the same things.
Method. Read the description under each plant.
- Read the cactus. The cactus needs little water.little water
- Read the water lily. The water lily lives in water, so it needs a lot of water.lives in water
- Choose the plant. So the cactus is the plant that needs the least water.cactus
- Write the answer. cactus
Check. A cactus lives where there is very little rain. ✓
| Pot | Average height (cm) |
|---|---|
| 1 plant in the pot | 24 |
| 2 plants in the pot | 19 |
| 3 plants in the pot | 13 |
Method. Find the biggest number in the height column.
- Read the heights. The heights are 24 cm, 19 cm and 13 cm.24, 19, 13
- Find the biggest. The biggest height is 24 cm, which is in the pot with 1 plant.24 cm is biggest
- Name the pot. So the pot with one plant gave the tallest plants.1 plant
- Write the answer. 1 plant in the pot
Check. The plants with room to grow were the tallest. ✓
Method. Think about the three plants you have read about.
- Read the plants. The cactus needs little water, and the water lily lives in water.different amounts
- Decide. Plants need different amounts of water, so Tom is not right.not right
- Write the answer. no
Check. Plants vary from plant to plant. ✓
Watch out
Watch out: a plant that needs little water is not the same as a plant that needs no water. Every plant needs some water, but the amount differs from plant to plant.
Try it at home or school (with a grown-up). With a grown-up, visit a park, a garden or the school grounds. Find two different plants that look very different. Write down what each one looks like, and where it grows. Do not pick or pull any plant. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “Where does this plant grow best? Does it need a lot of sun or a lot of water?” Let your child compare two plants and say how they are different.
Exercise 3D Room to grow, and how plants differ
Method. Think about what a plant needs space for.
- Think about the roots. Roots need space to spread out in the soil.roots spread
- Think about the leaves. Leaves need space to spread out in the light.leaves spread
- Write the answer. Accept any sentence that says the plant has space for its roots and leaves to spread out.
Check. Room to grow is space for the roots and leaves. ✓
Method. Think about the plant in the pond.
- Look at the picture. The plant with leaves floating on the water is in a pond.floating leaves
- Name the plant. That plant is the water lily.water lily
- Write the answer. water lily
Check. A water lily lives in water. ✓
Method. Think about the plant that needs little water.
- Think about the stem. A cactus has a thick stem that can store water.thick stem
- Name the plant. The plant with the thick stem is the cactus.cactus
- Write the answer. cactus
Check. A cactus needs little water. ✓
Method. Read the description under each plant.
- Read the labels. The sunflower is described as needing lots of light.lots of light
- Name the plant. So the sunflower needs lots of light.sunflower
- Write the answer. sunflower
Check. A sunflower grows tall in the light. ✓
Method. Think about what crowded plants do with light and water.
- Read the sentence. Crowded plants have to share the light and water.share
- Write the answer. share
Check. Crowded plants share the same resources. ✓
Method. Think about what a cactus needs.
- Read the sentence. A cactus needs little water.water
- Write the answer. water
Check. A cactus stores water in its stem. ✓
Method. Read the labels under the pots.
- Read the first pot. The first pot has 1 plant, with space around it.1 plant
- Read the second pot. The second pot has 3 plants, crowded together.3 plants
- Choose the pot with room. The pot with 1 plant has room to grow.1
- Write the answer. 1
Check. Only one plant is in the first pot. ✓
Method. Compare the number of plants in each pot.
- Read pot A. Pot A has 1 sunflower.1 sunflower
- Read pot B. Pot B has 2 sunflowers, so they must share.2 sunflowers
- Choose the pot. The sunflower in pot A has more room.pot A
- Write the answer. pot A
Check. Fewer plants in a pot means more room for each. ✓
| Pot | Average height (cm) |
|---|---|
| 1 plant in the pot | 24 |
| 2 plants in the pot | 19 |
| 3 plants in the pot | 13 |
Method. Take the smaller height away from the bigger height.
- Read the two heights. One plant pot has an average of 24 cm and the three-plant pot has 13 cm.24 and 13
- Find the difference. The difference is how much taller the plant with room was.24 − 13 = 11
- Write the answer. 11 cm
Check. 13 + 11 = 24, so the answer is right. ✓
Method. Think about what a crowded plant has to share.
- Think about the room plant. It has space and does not have to share the light and water.space
- Predict. So the plant with room to grow is predicted to be taller.room to grow
- Write the answer. the one with room to grow
Check. A prediction can be checked by measuring both plants. ✓
Method. Compare the two plants.
- Think about the cactus. A cactus needs little water.little water
- Think about the sunflower. A sunflower needs lots of light.lots of light
- Write the answer. No. Accept any difference, such as a cactus needs little water, and a sunflower needs lots of light.
Check. Plants vary from plant to plant. ✓
Method. Think about what crowded plants have to share.
- Think about sharing. Crowded plants share the light, water and nutrients.share
- Give the reason. So each plant gets less of what it needs, and may grow less well.gets less
- Write the answer. Accept any sentence that says crowded plants share the light, water and nutrients, so each plant gets less.
Check. Less of each need means slower growth. ✓