How Can We Sort Materials?

Your teacher says, "Can you sort these things into groups?" But how do you decide which things go together?

Everything around you is made of materials (that means stuff like wood, metal, plastic, and fabric). We can learn a lot about materials just by looking at them and touching them. The things we notice are called observable properties (that means things you can see, feel, or measure).

When we sort things, we put them into groups. We pick one property and put all the things that share it in the same group. This is called classifying.

Scientists sort things by looking very carefully. This is called observing. Let's be scientists and try sorting objects!

• Look at each object. What color is it? What shape is it?
• Touch each object. Is it smooth or rough? Hard or soft?
• Sort the objects into two groups. You pick the rule! (Example: "smooth things" and "rough things.")
• Try again! Sort the same objects a different way. (Example: "heavy things" and "light things.")

🌟 Great job! You just used the same objects but sorted them in different ways. That is what scientists do!

When we sorted objects, we found something interesting. The same object can go in different groups depending on which property we choose! A coin is smooth AND it is metal AND it is small. So a coin could go in the "smooth" group, the "metal" group, or the "small" group.

This means there is more than one right way to sort things. What matters is that you pick one clear rule and follow it for all the objects.

Look at the table above. Can you see that the coin and the paper clip are both smooth and both metal? They share two properties! That means they could be in the same group when you sort by texture OR by material.

When we sort things, we are looking for patterns. A pattern means something that happens the same way again and again. Let's look for patterns!

All metal things share some properties. They are usually hard, smooth, and shiny. All wooden things share some properties, too. They are usually hard, light in color, and not shiny. See the pattern? Things made of the same material often share the same properties.

This pattern works everywhere in science! Scientists look at animals and sort them into groups (birds, fish, mammals). Scientists look at rocks and sort them into groups (smooth rocks, rough rocks, sparkly rocks). Looking for patterns helps us understand the world.

People sort materials every day! Think about these examples:

Here is a fun challenge: Can you think of a way to sort the food in your kitchen? You could sort by color, by shape, or by whether it goes in the fridge or the pantry. You are an engineer when you figure out the best way to sort!

• Property — Something you can see, feel, or measure about an object. Color, shape, size, and texture are all properties.
• Observable — Something you can notice by using your senses (seeing, touching, hearing, smelling).
• Sort — To put things into groups based on a rule.
• Classify — Another word for sorting things into groups. Scientists classify things to understand them better.
• Material — What something is made of, like wood, metal, plastic, or fabric.
• Texture — How something feels when you touch it. It might feel smooth, rough, bumpy, or soft.