P3 Science Topical Notes (Latest MOE PSLE Syllabus)

eugene4251

Jan 25

7 min read

Updated: Jan 29

Primary 3 Science develops core observation and explanation skills through four themes: students distinguish living from non-living things using key characteristics and classify living things using observable features. They explore materials by linking everyday uses to physical properties and supporting ideas with observations. They also compare plant and animal life cycles by identifying and sequencing the main stages over time. Finally, students explore magnets as a way forces interact, describing attraction and repulsion, identifying key magnet characteristics, and everyday applications.

Last updated 20 January 2026

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Chapter 1: Living and Non-Living Things [Diversity]
Chapter 2: Materials [Diversity]
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Chapter 1: Living and Non-Living Things [Diversity]

Living Things

All living things have the following characteristics.

Characteristics of living things:

Need air, food and water to stay alive
To take in oxygen to carry out respiration to release energy
Can reproduce
To ensure the continuity of their own kind
When a type of living thing no longer exist → become extinct
Can grow
Can respond to changes in their environment

* Non-living things do not show all of these characteristics.

Classification of Living Things

Living things	How they obtain food	How they get energy
Plants	Make their own food through photosynthesis	Carry out respiration to release energy from food
Animals	Eat other living things for food
Fungi	Get food from dead matter and waste through decomposition
Bacteria	Get food from dead matter and waste through decomposition

*An organism is a living thing.

Animals

Animals have different appearances, types of outer body coverings and ways to reproduce.

Classification of Animals

Group	Characteristics
Mammals	Have hair or fur Most give birth to their young alive except spiny anteater and platypus which lay eggs Breathe through lungs most live on land, some in the sea Produce milk to feed the young mammals Warm-blooded
Reptiles	Have dry skin with dry scales dry scales are not scales of a fish Breathe through lungs Most reproduce by laying eggs Cold-blooded
Birds	Have feathers help them to fly and keep warm Have a beak, pair of wings and legs Breathe through lungs Reproduce by laying eggs Warm-blooded All birds have wings but not all can fly e.g. Ostriches, Penguins, Emus
Fish	Have scales Most reproduce by laying eggs except guppy and molly which give birth to young alive Breathe through gills Cold-blooded
Amphibians	Have moist skin Reproduce by laying eggs Live on land and in water. E.g. Adult frog: breathe through moist skin (water) breathe through lungs (on land) tadpole: breathe through gills Cold-blooded
Insects	Have 3 body parts and 6 legs (or 3 pairs of legs) Most reproduce by laying eggs Have exoskeleton Have a pair of feelers Cold-blooded

Plants

Plants are living things that can make their own food. They can grow on land and in water.

Classification of plants

Group	Characteristics
Flowering Plants	Can make their own food through photosynthesis Adult plants produce flowers which can develop into fruits that contain seeds Reproduce by seeds
Non-flowering Plants E.g. Ferns, Mosses	Can make their own food through photosynthesis Does not produce flowers Reproduce by spores In ferns, spore cases containing spores are found on the underside of the leaves

Fungi

Fungi cannot make their own food. They can grow on dead or living things. They obtain their food by breaking down dead matters or waste materials into simple substances and absorb them. The process is called decomposition so fungi are decomposers.

Mushroom, Mould and Yeast are examples of fungi.

Some mushrooms are edible
Yeast can be used to make bread
Some mould can be used to make cheese

Useful fungi can be made into medicine while harmful fungi can caused infections and food spoilage.

Fungi reproduce by spores. They are small and light so they can be easily carried by the wind. In some fungi, spores can be found in spore cases. For mushroom, spores are in the gills.

Conditions for the growth of fungi/ decomposition:

Presence of water / moisture
Presence of oxygen
Presence of warmth / suitable temperature

*can be easily remembered as WOW

Bacteria

Bacteria are microorganisms. They cannot be seen by the naked eye and requires a microscope to see them clearly.

Bacteria cannot make their own food. Similar to fungi, they are decomposers as well.

Favourable conditions for growth of bacteria:

Conditions for the growth of bacteria/ decomposition:

Presence of water / moisture
Presence of oxygen
Presence of warmth / suitable temperature

*can be easily remembered as WOW

Useful bacteria are used in food production while harmful bacteria can cause diseases.

Non-living things

Non-living things can be classified according to their characteristics and materials. Different materials have different properties such as strength and flexibility.

We will explore the properties of materials in chapter 2.

Chapter 2: Materials [Diversity]

Materials can be classified into two groups:

Natural materials: found naturally in nature
Man-made materials: made by humans

Classification	Sources	Examples of Materials
Natural	Animals	Fabric (Wool), Leather, Fabric (Silk)
	Plants	Wood, Rubber, Fabric (Cotton)
	From the ground	Glass, Metals, Ceramic
Man-made	Petroleum (then undergo man-made processes)	Plastics, Plastics (Nylon)

Common properties of materials

Properties of materials	Definition
Strength	The ability to be subjected to loads without breaking.
Flexibility	The ability to bend without breaking.
Ability to float/ sink in water	The ability to stay on/near the surface of water and not sink.
Waterproof	The ability to not absorb water.
Transparency	The ability to allow no/ some/ most light to pass through it.

Other properties such as Electrical conductivity and Heat conductivity will be explored in other chapters.

Use of materials

Materials	Physical properties	Use
Wood	Strong	Furniture, Boats
Metal	Strong Waterproof Not flexible Sink in water	Utensils, Tools, Lock
Ceramic	Strong Not flexible	Plates, Cups, Tiles
Rubber	Flexible Waterproof	Rubber band, eraser, gloves, balloons
Glass	Transparent Strong	Windows, spectacle lens
Plastic	Waterproof Strong	Bottles, containers, toys
Fabric	Not waterproof	Clothes, towels, gloves

Most of the materials have more than one property so we have to know their properties in order to make them into objects that meet our needs.

Chapter 3: Life Cycles of Plants and Animals [Cycles]

Life cycle of living things

A life cycle is a pattern that repeats the changes in the stages of an organism's life as it grows, develops and reproduces.

Life Cycles are important to ensure the continuity of its own kind.

Many eggs are laid at one time to increase the chance for some eggs to hatch into young and develop into adults to continue the life cycle.

3-stage life cycle

Egg -> Young -> Adult
Young of animal resembles the adult (except frogs)
The young stage can be called nymph if the animal is an insect

Examples of animals with 3-stage life cycle

Frog, Toad (Egg -> Tadpole -> Adult)	Adult frog: breathe through lungs when on land and through moist skin when in water Tadpole: breathe through gills in the water Adult and young live in different places because they do not need to compete for food, space and have different predators.
Cockroach	The young resembles the adult. Moulting: shedding of old skin to grow new skin, increasing its body size. shows that living things grow Adult cockroach, grasshopper and dragonfly have wings and can fly
Dragonfly
Grasshopper
Chicken, Human

Plants have three stages in their life cycle: Seed -> Young Plant -> Adult Plant

The roots emerge first followed by the shoot
Yong plant has leaves to make food through photosynthesis
Adult plant bear flowers which develops into fruits with seeds

4-stage life cycle

Egg -> Larva-> Pupa -> Adult
The larva does not resembles the adult
During larva stage, the animal is most active and consume most food. The larvae undergo moulting
During pupa stage, the animal does not consume any food and does not move
During adult stage, reproduction occurs

Examples of animals with 4-stage life cycle

Mosquito	Lays eggs in stagnant/still water Larva hangs from the surface of water Larva (wriggler) takes in oxygen from the surrounding air through its breathing tubes
Butterfly, Beetle, Moth

Chapter 4: Magnets [Interactions]

Magnets can be natural or man-made. A magnet can exert a force: a push (repel) or a pull (attract) on other objects made of metals.

Characteristics of magnets

Magnets can be made of magnetic materials: Iron or Steel - also electrical conductors
1. Some metals are non-magnetic. Examples: Copper, Aluminium, Gold and Silver
2. All non-metals are non-magnetic. Examples: Wood, Glass, Rubber, Plastic, Ceramic
All magnets have two poles at the ends: North pole and South pole.
1. Magnet is strongest at its poles. Weakest in the middle.
2. A freely suspended bar magnet points in the North-South direction when it comes to a rest.
When like poles of two magnets are facing each other, they will repel each other. When unlike poles of two magnets are facing each other, they will attract each other.
Magnets always attract magnetic materials, can never repel. Only magnets can repel each other.

Make a temporary magnet

Stroke method
1. Stroke iron rod with the same pole of the magnet in the one direction. The poles of the temporary magnet depends on the pole of the magnet in contact with the rod first.
2. The number of strokes affect the strength of the temporary magnet.
  1. Single-touch stroke
  2. Double-touch stroke
Electric method
1. Coiling wires around a rod made of magnetic material. When electricity passes through the wire (not the rod), rod is magnetised and becomes an electromagnet
2. The number of coils of wire around the iron rod and the number of batteries (amount of electricity in the circuit) affects the strength of the electromagnet.
3. An electromagnet has north and south poles.
4. An electromagnet is a temporary magnet.

Demagnetise a magnet (lose its magnetism)

Heating
Hammering
Dropping

Uses of magnets in everyday life

Magnets can be used:

Show directions: A compass
Lift objects in scrap yards using electromagnets
Hold objects in place
Display images on computer screens
In medical devices for diagnostics and treatments

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