There are many aspects to understanding matter and its interactions, according to the Next Generation Science Standards
. Students preparing for the TASC Test Assessing Secondary Completion™, for example, will want to be familiar with the periodic table of elements (pictured below).
Students might be asked to compare different elements. To be able to do that, students will need to know the characteristics of elements – in other words, the characteristics of matter. This knowledge can help test takers make comparisons and observe matter’s interactions through the use of simple chemistry.
There are three states of matter.
These three states are: solid, liquid, and gaseous. Solids
are rigid. They have a definite volume and shape, which is often unchanging or difficult to change. Liquids
are more fluid, and do not have a particular form or shape. Rather, both take the shape of the container they are placed into (to some extent).
It is possible for some substances to change states. According to Tanner’s General Chemistry
, “substances can be transformed from one state to another by heating or cooling.” Additionally, changes in pressure can change the substance’s state as well.
For example, water can exist in any of the three states. In it’s most common state, water is a liquid. When water is frozen, it becomes a solid – ice. Water is a gas when it evaporates.
Think of these three states in terms of molecules. In solids, molecules are very close together. In liquids, molecules are more spread out but not as spread out as in gases.
are the smallest bits of compounds. It’s important that students distinguish molecules from particles, which are the building blocks of matter.
There are two kinds of matter.
The first kind is material
, which itself can be divided into two categories. The first is a material that has a consistent composition throughout. Because of this consistent composition, these types of matter are often described as homogeneous
. Examples include metal, plastic, and even paper. The second, then, is heterogeneous
, which means it’s varied in composition. Examples of a heterogeneous material include particleboard and wood grains.
The second kind is a substance
, which has a rather definite chemical composition and is therefore always homogeneous. Substances usually refer to elements that have definite rations of components, including salt and nitrogen for example.
Matter interacts in four ways.
According to the Lawrence Berkeley National Laboratory’s Particle Data Group
, there are “four fundamental interactions between particles, and all forces in the world can be attributed to these four interactions.
These four fundamental interactions
, or forces, are:
- Strong: A force that holds the nucleus together. It counters the forces of repulsion of protons.
- Electromagnetic: A force that is created between charges and magnetic force. It depends on an exchange of photons.
- Weak: A force that is only effective at very short distances. It’s usually discussed in terms of beta decay.
- Gravity: A force that is always attractive and acts along the line joining the centers of mass of two pieces of matter. It’s similar to an electromagnetic force, but it’s the weakest of the four forces.