Properties of Matter

Matter is anything that has weight and takes up space. Solids, liquids and gases are all forms of matter.

You encounter many solids, liquids and gases daily. Common liquids include water, milk or juice. Air is a mixture of different gases like oxygen, nitrogen and carbon dioxide. Common solids include pencils, paper, foods and clothing.

A pencil is a solid object made of wood, carbon, rubber and metal. It is brittle (breakable), floats (and is therefore less dense than water) and is not soluble (does not dissolve in water). A sheet of paper is solid, not magnetic and not soluble. A metal fork is solid, magnetic, not soluble and more dense than water.

When two substances are combined, they could form a new substance. The properties of the combination needs to be observed to determine if a new substance has been formed.

Zoe knew that iron is magnetic and sodium is not so she tested each with a magnet.

Sodium metal reacts with water causing an explosion.

Sulfur hexafluoride is more dense than air. When placed inside a balloon, the balloon falls to the ground. Helium is less dense than air. A helium-filled balloon floats in air. A boat filled with air floats on top of Sulfur hexafluoride gas.

Although other gases could be burned for cooking in BBQ grills, propane gas is easily compressible into tanks.

Metal conducts heat, which means that it might cause your hand to be burned if used as the handle of a pot. Plastic is a better choice because it does not conduct heat as well as metal.

Swiss cheese is too soft to be an effective material for a knife and fork. It squishes rather than cuts. Stainless steel is hard and strong. It is even better than iron because iron rusts.

Magnetism: whether or not a material sticks to a magnet. Density: whether a material floats or sinks in water or air. Solubility: whether or not a material dissolves in water. These are all properties that can be used to describe solid, liquid and gases.

There are many answers to this question. Here are some examples:

Liquid water is non-magnetic and non-conductive. It is used for drinking, washing dishes and watering plants.

Water in the gas phase is also non-magnetic and non-conductive. It has a much lower density than liquid water. It is used for powering steam engines and some power plants.

Water in the solid phase (ice) is also non-magnetic and non-conductive. Surprisingly, it has a slightly lower density than liquid water. This is a unique property of ice and it is the reason that ice floats on water. If it didn't, all the fish in a frozen lake would get crushed! Ice is used to build igloos, keep food cold and to reduce swelling if you have an injury.

Knowing the properties of matter can help engineers pick the right types of materials for the job.