Scientists find out by looking closely
Scientists learn about the world by watching carefully. When you observe, you use your eyes, ears, nose and hands to notice details. A scientist doesn’t just glance at a leaf. They look at its colour, its shape, its edges and the tiny lines running across it.
After they observe, scientists do three more things: they measure, they compare, and they sort. Then they record what they found. You can do all of these things too.
Measuring with tools
You can guess how long a pencil is, but a guess might be wrong. A tool helps you measure more exactly.
| Tool | What it measures | Example |
|---|---|---|
| Ruler | How long something is | The crayon is 9 centimetres long. |
| Balance | Which thing is heavier | The apple is heavier than the grape. |
| Thermometer | How hot or cold something is | The water is 20 degrees. |
| Measuring cup | How much liquid there is | I poured 1 cup of water. |
When you use a ruler, line up the end of the object with the zero mark. Then read the number at the other end and say the unit, such as "9 centimetres." A number without a unit doesn’t tell us much. Nine what? Nine centimetres and nine metres are very different!
A balance has two sides. Put one thing on each side. The heavier side goes down, and the lighter side goes up. If both sides stay level, the two things weigh the same.
Measuring without a ruler
You can also measure with things you already have, such as paper clips, blocks or your hand. A book might be 8 paper clips long. Just be sure to use the same thing each time and to leave no gaps.
Comparing
When you compare, you look for what is the same and what is different.
- Is this rock bigger or smaller than that one?
- Is this leaf smooth or bumpy?
- Which cup holds more water?
Words like longer, shorter, heavier, lighter, warmer and cooler help us compare.
Sorting into groups
To sort means to put things into groups because they share something. You get to choose the rule. You might sort buttons:
- by colour: red buttons, blue buttons, yellow buttons
- by size: big buttons and small buttons
- by holes: two holes or four holes
The same buttons can be sorted many different ways. Scientists sort living things too. They put animals with feathers in one group and animals with fur in another.
Writing it down
Scientists record what they observe so they can remember it and share it. You can:
- draw a picture and label it
- make a chart with tally marks
- write a few words or numbers
A record helps you notice patterns you might forget later. If you measure a bean plant every day and write down its height, you can see how fast it grows.
In the real world
People measure and sort every day. A baker measures flour so the bread turns out right. A doctor uses a thermometer to check for a fever. At the grocery store, fruit is sorted into bins so shoppers can find what they need. Even your kitchen drawer is sorted, with spoons in one spot and forks in another.
Common mistakes
- Starting at the wrong spot on the ruler. Always start at zero, not at the edge of the ruler.
- Forgetting the unit. Say "5 centimetres," not just "5."
- Changing the sorting rule halfway. Pick one rule and stick to it.
Try it yourself
- Gather 10 small things, such as a crayon, a spoon and a leaf.
- Measure each one with a ruler or with paper clips.
- Use a balance to find the heaviest and the lightest.
- Sort them into two groups. Ask a friend to guess your sorting rule.
- Draw a picture of your groups and label them.
Quick recap
- Scientists observe closely, measure, compare and sort.
- A ruler measures length; a balance compares weight; a thermometer measures temperature.
- Always say the unit when you give a measurement.
- Sorting means making groups that share something.
- Recording helps you remember and share what you found.