# Pocket Genius Science: Matter and materials – Properties of matter

## Facts At Your Fingertips: Matter and materials – Properties of matter

Different substances have different properties. They might be hard or soft, flexible or rigid, flammable or not.

Testing the properties of a particular substance helps in determining what it can, and cannot, be used for.

### Mass and density

The amount of matter within an object is known as its mass. On Earth, the force of gravity pulls on the mass of an object to give it weight. An object’s density is how much mass it has for its size.

For example, a piece of iron weighs more than a feather of the same size because it is a denser material.

### Plasticity

Some materials can be shaped into a different form. This property is known as plasticity. Modeling clay, for example, can be shaped into various objects.

Special types of plasticity include malleability, where a material such as metal can be beaten into thin sheets, and ductility, which allows a material to be pulled into a thin wire.

### Hardness

The hardness of minerals is measured using the Mohs scale.

Ranging from 1 (soft) to 10 (very hard), the scale measures how well one mineral can resist being scratched and shaped by another.

A diamond could scratch any other mineral, but talc can easily be scratched by any mineral, or even a human fingernail.

### Elasticity

Some materials are very flexible and have the ability to bend. Some are so flexible that they can bend or stretch in different directions, but still return to their original shape, size, or position. This property is known as elasticity. A rubber band is an elastic object.

Many materials cannot be stretched beyond a certain point, which is called the elastic limit.

### Flammability

If a material is flammable, it catches fire (ignites) easily and then burns (combusts). Highly flammable materials, such as gasoline, can be dangerous, but also very useful.

Flammable materials produce heat as they burn. A material that will not burn is known as nonflammable.

### Solubility

If a material can dissolve in a liquid, it is known as soluble. The liquid into which the soluble material dissolves is a solvent.

Water is often called the universal solvent because so many materials can dissolve in it. Soluble materials include solids, liquids, and gases.

### Conducting electricity

All metals are good electrical conductors, which means they allow electrical currents to pass through them easily. Copper is widely used in electrical wiring.

Insulating materials, such as glass and plastic, are poor electrical conductors. They are used to prevent electricity from flowing where it is not needed, such as through our bodies.

### Conducting heat

Metals conduct heat well and are known as thermal conductors. Other materials, such as glass and plastic, do not conduct heat easily.

They are called thermal insulators and they are very useful as they prevent heat from escaping.