Choosing the Right Material for Every Job!

Every object around you is made from a material. You use materials every day wood, plastic, metal, wool, rubber, and fabric are all materials. Each material has special properties that make it good for certain jobs.

When you choose a material, you think about what the material needs to do. A boat needs to float, so you pick wood or plastic. Mittens need to keep you warm, so you pick wool.

A material's properties tell you what it can do. Some materials are waterproof they do not let water pass through. Some materials are strong they do not break or bend easily. Some materials are lightweight they are easy to carry and lift.

When you pick a material for a job, you match the property to the need. If something needs to stay dry, you pick a waterproof material like plastic or rubber. If something needs to be sturdy outside, you pick a strong material like wood or metal.

Here are materials you will see in your practice questions and what makes each one special:

• Plastic waterproof and lightweight; great for watering cans, lunchboxes, umbrella covers, and sleds.
• Wood strong and sturdy; great for birdhouses, boat hulls, plant pots, and paintbrush handles.
• Metal very strong and hard; great for watering cans, playground slides, and drum surfaces.
• Wool warm and soft; great for mittens and winter clothing.
• Rubber waterproof and flexible; great for boots worn in snow or rain.
• Fabric/Nylon lightweight and flexible; great for kite sails, beach umbrellas, and rain umbrellas.
• Glass/Clear Plastic transparent; great for windows and weather viewers that let light through.

Material: A material is what an object is made from. Wood, plastic, metal, wool, rubber, and fabric are all materials you use every day.

Property: A property is something that describes what a material is like or what it can do. Being waterproof, strong, or lightweight are all properties.

Waterproof: When a material is waterproof, water cannot pass through it. Plastic, rubber, and metal are waterproof materials. You need waterproof materials for umbrellas and boots.

Strong: A strong material does not break or bend easily. Wood and metal are strong materials. You need strong materials for birdhouses and playground slides.

Lightweight: A lightweight material is not heavy. Tissue paper and fabric are lightweight. You need lightweight materials for kites so they can fly in the wind.

Transparent: A transparent material lets light pass through it so you can see through it. Clear glass and clear plastic are transparent. You need transparent materials for windows and weather viewers.

Flexible: A flexible material can bend without breaking. Fabric and rubber are flexible. You need flexible materials for umbrellas and boots.

Absorb: When a material absorbs water, it soaks the water up like a sponge. Cotton and cardboard absorb water, which means they are not good choices when you need to stay dry.

Dissolve: When something dissolves in water, it breaks apart and disappears into the water. Sugar cubes dissolve in water, so they would never work for a boat or a watering can.

Durable: A durable material lasts a long time and does not wear out quickly. Metal and wood are durable materials that work well outdoors.

You can practice choosing materials by thinking about the job first. Ask yourself: Does this need to stay dry? Does this need to be strong? Does this need to be light?

Try these examples at home or in class. What material would you use to make a toy boat that floats? What material would you use to make mittens for a snowy day? What material would you use to make a window you can see through?

Each time you answer, think about the properties of the material and match them to the job. This is exactly what scientists and builders do every day!

You already know that objects around you are made from different materials. You have seen wood, plastic, metal, and fabric in your home and classroom. This topic builds on what you know about everyday objects and helps you think more carefully about why each material is used.

Understanding material properties is an important part of learning about how things change and how we make smart choices in science.

This topic is part of the Changes chapter in science. As you learn about selecting materials for specific purposes, you are building important thinking skills that connect to many areas of science.

You are learning to observe, compare, and make decisions skills that will help you in all your future science topics. Choosing the right material is one of the first steps in understanding how materials behave and how they can change when conditions around them change, like getting wet, hot, or cold.

Keep exploring science topics to discover more about how materials work in the world around you!