Matter, Atoms, and Properties

Matter and Atoms

Matter: Matter describes everything we can see, touch, smell, or feel. In other words, matter is anything that has mass and takes up space (including air and almost everything else).

Atom: An atom is the smallest unit of matter. If you chop a piece of metal into a bajillion (not a real number) pieces, the smallest bit you are left with that still has the properties of the metal is called an atom.

Atomic Models

Atoms are made of smaller particles -

1. Protons - Positively charged particles.
2. Neutrons - Particles without any charge.
3. Electrons - Negatively charged particles with almost no mass
4. Nucleus - The center of an atom, formed by protons and neutrons.

Physical Properties

The way something looks, feels, smells, and tastes are all physical properties. It’s easy to classify matter by these characteristics. Some common physical properties used to study matter are:

1. Malleability: How easily something can be flattened, shaped, or pressed
2. Color
3. Size
4. Density
5. Magnetism: Whether or not something is magnetic
6. Boiling Point and Melting Point: The temperature at which something boils or melts
7. Solubility: How easily something dissolves in another substance.

Physical Change: A physical change is any change to the physical properties of matter such as its size, shape, or state (solid, liquid, or gas/vapor). The final product of any physical change is still made of the same matter. For example, you can revert ice, snow, or vapor back to water by either heating or cooling it. Ice, vapor, and water are all the same matter--just in different states.

Chemical Properties

Chemical properties describe the ability of something to undergo different chemical changes. Some examples are:

1. Flammability: How easily something lights on fire
2. Reactivity: How reactive something is to oxygen, water, light, etc.

Chemical Change: When any of these chemical properties changes, the matter has gone through a chemical change. Rust on an iron gate or a log burning and producing ashes are both examples of chemical changes. Some signs of chemical changes may include:

1. Change in color: This is like when you leave a sliced apple out and it turns brown.
2. Change in energy: The chemicals react, releasing energy in the form of bright lights and heat (like fireworks).
3. Change in odor: The smell/odor changes. Think of food going rotten.
4. Formation of a gas or solid: When you add two substances together, such as vinegar and baking soda, you frequently see bubbles. Bubbles, or gas formation, are a sign that the ingredients have undergone a chemical change.

Chemical changes are often MUCH harder to reverse than physical ones--just imagine trying to turn ashes back into a log of wood.