Science notes, unit 1

Scientific skills

Textbook Science Year 3 (DLP), pages 1–22

What this chapter covers

You can observe things using all five senses (1.1.1)
You can sort things into groups by what they look like or how they feel (1.1.2)
You can measure length with a ruler and time with a stopwatch, using the right units (1.1.3)
You can make an inference, a sensible reason for what you see (1.1.4)
You can predict what will happen next using clues and patterns (1.1.5)
You can share information using tables, bar charts and drawings (1.1.6)
You can use, handle, sketch, clean and store science apparatus and specimens correctly (1.2)

Scientists find out about the world in careful ways. These ways are called scientific skills. You use some of them every day without knowing it! In this unit you will learn two kinds: science process skills (ways of thinking) and manipulative skills (ways of using your hands).

1.1Science process skills

There are six science process skills in Year 3. Let us learn them one by one.

Observing

Observing means using all of our senses to get information about an object or something that happens.

We have five senses. Each sense has its own body part.

Sense	Body part	Example at Pak Mat's stall
Sight	Eyes	The cendol is green and colourful.
Hearing	Ears	The ice grating machine makes a loud sound.
Smell	Nose	The banana fritters smell nice.
Taste	Tongue	The cendol is sweet.
Touch	Skin	The cendol bowl feels cold.

Four children eating cendol and banana fritters at a stall, talking about what they see, hear, smell, taste and feel — Aishah, Kina, Lim and Langgi use all their senses at Pak Mat's stall.

Two boys watching fireworks; one covers his ears — Fireworks: we **see** the bright colours and **hear** the loud bangs.

We can also observe changes. Touch the leaves of a mimosa plant (pokok semalu). The leaves fold up! After a while, they open again.

Mimosa plant before, when and after being touched — After being touched, the mimosa leaves fold up. Later they open again.

Did you know? Your tongue and nose work together. When you have a blocked nose, food tastes less yummy!

Never taste or smell anything in the Science Room unless your teacher says it is safe.

You hold a durian. Which senses can you use to observe it?

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Sight (green and spiky), smell (strong smell), touch (thorny skin) and taste (sweet flesh).

Classifying

Classifying means sorting things into groups by the characteristics they share. A characteristic is something special about a thing, like its colour, shape, size or texture.

Langgi helps his grandfather sort stamps. They look at the shape. Some stamps are triangles. Others are rectangles.

Stamps sorted into two groups: triangle and rectangle — Stamps sorted by **shape**.

We could also sort the same stamps by colour or by size. You can sort the books in your school bag too: thick and thin, hard cover and soft cover.

Example: sorting animals

A cat, a rabbit, a chicken and a duck. Group 1: animals with fur (cat, rabbit). Group 2: animals with feathers (chicken, duck).

Measuring and using numbers

Measuring means observing with numbers and standard units. A standard unit is a unit everyone uses, like centimetre (cm) or second (s).

What we measure	Tool	Unit
Length (how long)	Ruler	centimetre (cm)
Time (how long it takes)	Stopwatch	minute (min) and second (s)

Measuring length with a ruler

Put one end of the object in line with the "0" mark.
Put your eye straight above the other end. Do not look from the side.
Read the number and write the unit.

A wooden block from 0 to 9 cm on a ruler; the eye straight above the end is correct — Correct eye position: straight above the end. The block is 9 cm long.

A crayon from 0 cm to 5 cm on a ruler — Try it: the crayon starts at 0 and ends at 5. It is 5 cm long.

Measuring time with a digital stopwatch

Push the reset button so the time shows zero.
Push the start button to start.
Push it again to stop. Then read the time.

Digital stopwatch showing 03:59 29 — The big numbers on the left are **minutes**. The next big numbers are **seconds**. This shows 3 minutes 59 seconds.

Did you know? The tiny numbers at the end of a stopwatch show parts of a second. Fast runners can win by just a tiny part of a second!

Always write the unit. "9" is not enough. Write 9 cm.

Making inferences

An inference is a sensible first reason (initial conclusion) that explains what we observe.

Observation	+ Sensible reason	= Inference
The plant is green and fresh.	Plants need water to grow well.	Maybe the plant is watered every day.
The plant is wilted and the leaves are yellow.	The soil looks dry.	Maybe the plant did not get enough water.

A girl looking at a wilted plant with yellow leaves — What could be wrong with this plant?

An inference may be true or false. The wilted plant could also lack fertiliser, or insects could have attacked it.

Observing or inferring?

Observation: The floor of the school canteen is wet.
Inference: Maybe someone spilled a drink. Maybe the cleaner just mopped it.

Your torch does not light up. Make one inference.

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Maybe the batteries (dry cells) are flat. / Maybe the batteries are not put in properly. / Maybe the bulb is broken.

Predicting

Predicting means saying what will happen next, based on observations, past experience, data or patterns.

Predicting is not guessing. A guess has no clues. A prediction uses clues.

Cream flowers on a cake: white, red, yellow, white, red, yellow — The flowers go white, red, yellow, white, red, yellow. The next one will be **white**.

Dark clouds and lightning in the sky? We can predict that it will rain soon. We can make more than one prediction. Predictions may be true or false.

Look at Aishah's beads. Predict the colour of the next bead.
A hand threading beads of different colours

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Green or blue (textbook answer).

Communicating

Communicating means sharing information using words or pictures such as tables, graphs, diagrams or models.

Year 3 pupils asked their friends about their favourite fruits. They wrote the answers in a table. Then they drew a bar chart from the table.

Table: papaya 8, durian 9, banana 7, watermelon 6 — The table of favourite fruits.

Bar chart of favourite fruits: papaya 8, durian 9, banana 7, watermelon 6 — The same information as a bar chart.

In the bar chart, each fruit gets a bar. The taller the bar, the more pupils like that fruit. Durian has the tallest bar (9 pupils), so it is the favourite. Watermelon has the shortest bar (6 pupils).

Did you know? Posters, picture charts, pie charts and even storytelling are ways of communicating too.

1.2Manipulative skills

Manipulative skills are skills that use our hands and body in a science investigation, like holding, sketching and washing.

Pupils in a Science Room handling apparatus, washing a beaker and storing apparatus — Which pupils are handling, cleaning and storing apparatus?

Handling apparatus and specimens

A specimen is a living thing or a sample we study, like an insect, a leaf or some soil. Kina and Lim catch a grasshopper.

Use a net to catch an insect gently.
Put it in a jar. Cover the jar with a cloth with holes so it can breathe.
Put a leaf inside so it has food.
Take only one. Do not take too many specimens.
Use a hand lens to see small parts more clearly.
Release the insect after you finish.

A jar covered with a red cloth with holes — A cloth with holes lets air into the jar.

Never throw soil or specimens into the sink. The sink will get blocked. Use wooden tongs (a test tube holder) to hold a hot test tube.

Sketching

Sketching means drawing a diagram to record information. A good sketch is clear, accurate and labelled.

Use a ruler to draw straight lines. Then label each part with a straight line pointing to it.

Labelled sketch of a beaker with solution — Labelled sketches of a beaker (solution, beaker) and a test tube (stopper, test tube, solution).

Labelled sketch of a test tube with stopper and solution — Labelled sketches of a beaker (solution, beaker) and a test tube (stopper, test tube, solution).

Cleaning and storing apparatus

After an investigation, look after the apparatus in three steps:

Three steps: cleaning, drying and storing apparatus — 1 Clean it, 2 dry it, 3 store it in the right place.

Did you know? Test tubes are dried upside down on a rack so the water drips out.

True or false? "We should label every sketch."

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True. Every sketch should be labelled correctly.

Fun at home: the magic balloon

Put a balloon on the mouth of an empty bottle. Stand the bottle in ice. The balloon goes floppy. Predict what happens in warm water. (Ask an adult to help with hot water.)

A balloon on a bottle standing in ice cubes — Observe, predict, then check your prediction!

Pictures: Science Year 3 (DLP) textbook, pp. 1–22 (stall p. 1, fireworks p. 2, mimosa p. 3, stamps p. 5, stopwatch p. 6, ruler p. 7, plant p. 9, cake p. 11, fruit table and bar chart p. 13, beads p. 22, Science Room p. 15, jar p. 16, sketches pp. 18–19, cleaning p. 20, balloon p. 21). The crayon ruler is drawn for this site.

Summary

Skill	What it means	Quick example
Observing	Using all five senses	The nasi lemak smells nice.
Classifying	Sorting by characteristics	Stamps by shape
Measuring	Using numbers and units	Pencil = 7 cm
Making inferences	A sensible first reason	Maybe the plant needs water.
Predicting	Saying what will happen next	Dark clouds, so it will rain.
Communicating	Sharing with tables, charts, pictures	Bar chart of favourite fruits
Manipulative skills	Using hands correctly	Handle, sketch, clean, dry and store