Scientific Inquiry & Properties of Matter
Think like a scientist, then describe matter by its mass, volume, weight and properties.
Lesson objectives
By the end of this lesson, you should be able to:
- Use the science process skills: observing, comparing, classifying, inferring, hypothesizing and concluding.
- Plan a fair test by naming the independent, dependent and controlled variables.
- Tell the difference between mass, volume and weight.
- Describe materials by their properties, such as absorbency, hardness, brittleness and malleability.
Why does a cotton towel dry your wet hands while a plastic bag does not? Scientists answer questions like this by observing carefully, testing fairly and describing the properties of matter.
1. Thinking like a scientist
Scientists use science process skills to find answers. You use them too, every time you look closely at something and try to explain it.
| Skill | What it means | Example |
|---|---|---|
| Observation | Gathering information using the five senses: sight, hearing, smell, taste and touch. | You look at sandpaper and feel it: it is brown and rough (sight and touch). |
| Comparison | Finding how things are alike and how they are different. | Greg and Mino list the similarities and differences between a river and a lake. |
| Classification | Grouping things by a shared property. | Sorting objects into "floats" and "sinks". |
| Inference | An educated guess or explanation based on what you observed and already know. | The ground is wet, so you infer that it rained. |
| Hypothesis | A testable prediction, often written as "If…, then…". | "If the bulbs are replaced, then the flashlight will light up." |
| Experimentation | Testing a hypothesis with a planned, fair test. | Timing how fast a tablet dissolves in warm and cold water. |
| Conclusion | The final statement based on the results. It says whether the hypothesis was supported. | "Tablets dissolve faster in warm water." |
Notice the difference: "I think the flashlight has a bulb" is only a guess. A hypothesis can be tested, and its "If…, then…" form tells you what to do and what to look for.
2. Planning a fair test
A variable is anything that can change in an experiment. In a fair test you change only one thing at a time.
- Independent (manipulated) variable – the one thing you deliberately change. Example: the temperature of the water.
- Dependent (responding) variable – what you measure to see the effect. Example: the time it takes the tablet to dissolve.
- Controlled variables – everything you keep the same. Example: the same amount (volume) of water, the same kind of tablet, the same cup.
Why keep the volume of water the same in every trial? So the test stays fair and controlled: only the temperature changes, so only the temperature can explain the result.
3. What is matter?
Matter is anything that has mass and occupies space. Your pencil, the water you drink and even the air in a balloon are all matter.
| Quantity | Meaning | How we measure it |
|---|---|---|
| Mass | The amount of matter in an object. | With a platform balance or triple beam balance, in grams (g) or kilograms (kg). Mrs. Masipag measures the mass of an inflated balloon this way. |
| Volume | The amount of space an object takes up. | In millilitres (mL), litres (L) or cubic centimetres. Mr. Matipid describes the space inside a metal box. |
| Weight | The pull of gravity on an object's mass. | With a spring scale, in newtons. It changes when gravity changes. |
Gravity on the Moon is only one-sixth of Earth's. An astronaut's weight on the Moon becomes one-sixth as much, but the astronaut's mass stays the same, because the amount of matter in the body does not change.
4. Properties of materials
A physical property describes how a material looks or behaves. We choose materials for a job because of their properties.
| Property | Meaning | Examples |
|---|---|---|
| Absorbency | Able to soak up or take in liquids easily. | Cotton, sponge, tissue and paper are absorbent. |
| Hardness | How well a material resists being scratched. Compared using the Mohs hardness scale from 1 to 10. | Talc is the softest (1). Diamond is the hardest natural mineral (10). Diamond is hard, not soft! |
| Brittleness | Breaks, cracks or shatters easily when hit or bent. | Glass, ceramic plates, chalk. |
| Malleability | Can be hammered, rolled or pressed into thin sheets and shapes without breaking. | Gold, copper, aluminium foil. |
| Ductility | Can be pulled into thin wires. | Copper wire. |
| Elasticity | Returns to its shape after being stretched. | A rubber band. |
Review at a glance
The big ideas
- Scientists observe, compare, classify, infer, hypothesize, experiment and conclude.
- A fair test changes one variable, measures another and keeps the rest the same.
- All matter has mass and occupies space.
- Mass stays the same everywhere; weight changes with gravity.
- Materials are chosen for their properties: absorbent, hard, brittle, malleable, elastic.
Key terms & meanings
- Observation
- Gathering information with the five senses.
- Inference
- An educated guess based on observations and facts.
- Hypothesis
- A testable "If…, then…" prediction.
- Conclusion
- The final statement that says whether the hypothesis was supported.
- Independent variable
- The factor you deliberately change.
- Dependent variable
- The result you measure.
- Mass
- The amount of matter in an object.
- Volume
- The amount of space an object occupies.
- Weight
- The pull of gravity on an object's mass.
- Mohs scale
- A 1–10 scale of mineral hardness, from talc (1) to diamond (10).
Matter has mass and takes up space; we measure mass with a balance, volume in litres or millilitres, and weight changes with gravity.
Study tip: Cover the meanings, explain each term in your own words, then try the practice. Use Reshuffle and practise again until you can get every item right.