Egypt Primary 5 Science, Week 3: Seeds on the move

Leaves, seeds and ecosystems

Week 3 · Theme 1 Systems, Unit 1 Interactions of Organisms, Concept 1.1 Plant Needs (C) and Concept 1.2 Energy Flow in Ecosystems (A) · 3 lessons

Seeds on the move

Discovery Education Science P5: Term 1, Unit 1, pp. 34–41

GoalExplain how seeds are carried away from the parent plant and how to write a claim, evidence and reasoning.

New words

seed dispersal · the way seeds are carried away from the parent plantflower · the part of many plants that makes seedsmodel · a copy or drawing used to test or explain a real thing

Explanation

A plant uses the food it makes to grow and to make flowers. Flowers help plants make seeds, and seeds grow into new plants. A seed that falls right under its parent has little light, water or space. So many seeds travel. Light seeds with fluff or wings are carried by the wind. Some float away on water. Others hitch a ride on animals: burrs stick to fur and socks, and animals eat fruit and drop the seeds far away. Some pods split open and throw seeds out. To explain a result like a scientist, write a claim (a one-sentence answer), the evidence (what you saw) and the reasoning (why the evidence supports the claim).

Way to travel	Seed feature	Example
wind	fluff or wings	fluffy poplar seeds
water	light and waterproof	coconut
animals	hooks, or tasty fruit	burrs; dates
splitting pod	pod dries and snaps open	pods of some plants

Worked examples

Model seed	Distance (cm)
with wings	150
no wings	40

Mina builds a paper model seed. Dropped from 1 m in front of a fan, the one with paper wings lands 150 cm away and the one without wings lands 40 cm away. The wings helped it travel 150 − 40 = 110 cm farther.

Part	What it says
Claim	Plants need light to grow well.
Evidence	After 9 days the bean in the light was green and sturdy; the one in the dark was pale and thin.
Reasoning	Leaves use light to make food, so a plant without light cannot make more food.

A claim, evidence and reasoning about what plants need:

Coconuts have a thick, light husk and float. A coconut that falls from a palm by the sea can drift on the waves to a faraway beach and sprout there.

Class activity

Model seed test (a grown-up helps). Make two paper model seeds from the same paper: one with paper wings and one folded small without wings. Drop each from the same height outdoors on a windy day, or in front of a small fan, and measure how far each lands with a ruler or tape. Do it three times and write the results in a table. Which design travels farther? Then write a claim, evidence and reasoning.

Practice

Name three ways seeds can travel away from the parent plant.

A seed has light fluff. Which way is it likely to travel?

A winged model seed lands 120 cm away and a wingless one lands 30 cm away. How much farther did the winged seed go?

Model seed	Distance (cm)
winged	120
wingless	30

Why is it good for a seed to land far from its parent?