Grade by Grade
C. Matter and Energy · Properties of and Changes in Matter

The Right Stuff: Properties Make Materials Useful

C2.7 A3.1 A3.3 A1.2About 45 minutes
Learning goals
  • I can explain why the properties of a solid, liquid or gas make it useful for a certain job.
  • I can choose a material for a job by thinking about the properties it needs.
  • I can describe how First Nations and Inuit technologies use the properties of natural materials.

Words to know

material
The matter something is made of, like wood, steel, wool or plastic.
application
A use, or a job something is used for.
insulator
A material that slows down the flow of thermal energy. Wool and trapped air are good insulators.
conductor
A material that lets thermal energy or electricity flow through it easily. Metals are good conductors.
waterproof
Does not let water through.

Why not a chocolate teapot?

A teapot made of chocolate would melt. A winter coat made of paper would rip and get soggy. A bike tire filled with sand would be heavy and bumpy. Engineers and designers choose materials because of their properties. The right properties make a material useful for a job.

Solids and their jobs

  • Steel is strong and hard → bridges, nails, tools.
  • Copper lets electricity flow easily (a good conductor) and bends without breaking → electrical wires.
  • Rubber is flexible, waterproof and grippy → boots, tires, hockey pucks.
  • Glass is transparent and waterproof → windows, jars.
  • Wool traps air, so it is a good insulator, and it stays fairly warm even when damp → mittens, socks, toques.
  • Wood is strong for its weight and easy to cut → houses, furniture, hockey sticks.
  • Plastic is light, waterproof and can be moulded into any shape → containers, helmets, toys.
Knitted wool mittens, a knitted toque and a pair of green rubber boots sit on a wooden bench by a door in winter.
Each item is made from a material chosen for its properties: wool traps air to keep hands and heads warm, and rubber is waterproof and flexible for boots. AI-generated image
materialpropertyuseful forsteelstrong, hardbridges, nails, toolscopperconducts electricity, bendselectrical wiresrubberflexible, waterproof, grippyboots, tiresglasstransparent, waterproofwindows, jarswooltraps air (insulator)mittens, toques
Each material is matched to a job because of its properties. The property explains the use.

Liquids and their jobs

  • Water dissolves many things and flows easily → washing, cooking, making soup and drinks.
  • Oil is slippery → it helps the parts of a bike chain slide past each other smoothly.
  • Maple syrup has a high viscosity → it stays on your pancakes instead of running straight off.
  • Windshield washer fluid for winter stays liquid far below 0 °C → it cleans car windshields in winter without freezing. (It is poisonous: never drink it.)

Gases and their jobs

  • Air can be compressed and springs back → bike tires, air mattresses, bubble wrap that protects packages.
  • Trapped air is a great insulator → puffy winter jackets, the space between two panes in a window, snow on top of the ground.
  • Helium is lighter than air → it makes balloons float.
  • Carbon dioxide dissolves in drinks under pressure and makes bubbles → sparkling water. It also doesn't burn, so some fire extinguishers use it.

First Nations and Inuit technologies

For thousands of years, First Nations and Inuit peoples have chosen materials with the exact properties a job needs. These technologies are still made and used today.

  • Birchbark canoes (made by many First Nations, including Anishinaabe peoples): birchbark is light, waterproof and flexible. A frame of cedar, which is light and strong, gives the canoe its shape. The bark is sewn with spruce roots, and the seams are sealed with spruce gum (pitch), which is sticky when warm and hardens when cool, keeping water out.
  • Snow houses (Inuit): packed snow is full of tiny pockets of trapped air, so it is a good insulator. Inside a well-built snow house, it stays much warmer than the freezing wind outside. Some Inuit still build them when travelling and hunting on the land.
  • Caribou clothing (Inuit and some First Nations): caribou hairs are hollow and full of air, so caribou skin clothing is very warm and light.
Worked example

Let's choose materials for a winter mitt

Design a mitt for building snow forts. What properties does it need, and which materials have them?

  1. Job 1: keep hands warm. Needs an insulator that traps air → wool or fleece lining.
  2. Job 2: keep snow from soaking in. Needs a waterproof outside → a nylon or plastic-coated shell.
  3. Job 3: let fingers move. Needs flexible materials → soft fabric, not stiff plastic or metal.
  4. Job 4: grip snow blocks. A grippy palm → a rubbery patch.

A good mitt: a waterproof, flexible shell, a wool or fleece lining that traps air, and a grippy palm. Each material is chosen for its properties.

outside shell: waterproof,flexible (nylon)lining: wool orfleece traps airpalm patch: grippy(rubbery)cuff keeps snow out
The snow-fort mitt from the example. Every part uses a material with the right property for its job.
Just for fun

What do you call a teapot made of chocolate?

A melt-down waiting to happen! (Chocolate starts to melt even below body temperature, so hot tea would not stand a chance.)

Hands-on activity

Material match-up and waterproof test

You need: 5 scraps of different materials (for example a cotton cloth, a piece of wool sock, a plastic bag, a piece of an old nylon jacket or umbrella if you have one, a paper towel), a medicine dropper or teaspoon, water, a timer, paper towels to clean up.

Part 1: Match-up. Find 8 objects at home. For each, record: object, material, a property, and why that property is useful. Example: window, glass, transparent, lets light in. Include at least one liquid and one gas (like the air in a ball).

Part 2: Waterproof test.

  1. Question: Which material would make the best raincoat?
  2. Predict.
  3. Lay each scrap over a dry paper towel. Put 5 drops of water on each (same amount on each: fair test!).
  4. After 1 minute, lift each scrap. Is the paper towel underneath wet?
  5. Conclude: Which materials are waterproof? Which would make a good raincoat? Which would make a good towel?

What to look for: plastic and nylon usually keep the paper towel dry (waterproof). Cotton and paper towel soak through (absorbent). Wool may hold drops on top at first, then soak in.

Safety: ask a grown-up before using any fabric. Never use or test products like windshield washer fluid or cleaners.

Your turn

1

Why are electrical wires made of copper?

2

Why are winter jackets puffy?

3

Why is oil put on a bike chain?

4

Why do helium balloons float?

5

Name two properties of birchbark that make it good for canoes.

6

Why does a snow house stay warmer inside than the wind outside?

More practice: warm-up

1

Which property makes glass good for windows?

2

Which property makes rubber good for boots?

3

Which property of air makes it good inside bike tires?

4

Why does maple syrup stay on a pancake?

5

Why are hammers made of steel, not plastic foam?

More practice: on your own

1

Why must winter windshield washer fluid be different from plain water?

2

Why do some fire extinguishers use carbon dioxide?

3

Why is spruce gum useful for sealing a birchbark canoe?

4

Why does caribou skin clothing keep people very warm?

5

In the waterproof test, why did everyone get exactly 5 drops?

Challenge

1

A cooking pot usually has a metal bottom and a plastic or wooden handle. Explain both choices.

2

Bubble wrap protects a glass jar in the mail. Which state of matter does the job, and which property makes it work?

3

Choose a material for a lunch bag that keeps a drink cold. Give two properties it needs and explain.

Check your understanding

Quiz

1.

Electrical wires are made of copper because copper...

2.

Puffy winter jackets keep you warm because...

3.

Which gas makes party balloons float?

4.

Birchbark is a good canoe material because it is...

5.

Which property makes oil useful on a bike chain?

6.

Why is packed snow a good insulator for a snow house?

For parents and teachers

Big idea: Ontario Grade 5 expectation C2.7 asks children to explain why specific physical properties of various solids, liquids and gases make them useful for particular applications. The lesson connects to practical applications (A3.1), First Nations and Inuit technologies (A3.3), and a fair test (A1.2).

How to help: Ask "Why is this made of that?" about everyday objects: mitts, pots, windows, boots, jackets. Encourage answers that name a property.

Common difficulties:

  • Naming a material without a property. Push for "because it is...".
  • Thinking coats make heat. They slow thermal energy from leaving your body.
  • Forgetting liquids and gases can be useful materials too.
  • When discussing First Nations and Inuit technologies, present them as living knowledge that communities still use and teach today.

Safety: windshield washer fluid and antifreeze are poisonous: keep them out of reach and don't use them for experiments.