Physical Science Definition, Branches & Examples

Chemistry

The study of chemistry focuses on the properties and transformations of matter. All matter is made of atoms. There are different kinds of atoms, each one known as an element. The known elements can all be found on the periodic table of elements. Each element has its own special configuration of protons, neutrons and electrons that help determine with which types of other atoms it can bond. Under certain conditions, the atoms of one or more pieces of matter may break their bonds. The atoms then rearrange and bond together in a different way making a brand-new substance often with different properties than the original substance or substances. A popular children's chemistry experiment of combining baking soda and vinegar resulting in a bubbly eruption is scientifically explained by chemistry. The baking soda, {eq}NaHCO_3 {/eq}, and the vinegar, {eq}CH_3COOH {/eq}, break their bonds and join together in a different order as sodium acetate, {eq}Na_2C_2H_3O_2 {/eq}, carbon dioxide, {eq}CO_2 {/eq}, and water, {eq}H_2O {/eq}.

Scientists who investigate creative ways to make items from raw materials are practicing chemistry. Currently, scientists are investigating ways to make more eco-friendly plastics called bioplastics. Chemistry is also used in recycling. By rearranging the carbon and hydrogen chains in plastics, one plastic can become a different kind of plastic. For example, a rigid plastic milk jug made of high density polyethylene can be made into a softer plastic baggie of low density polyethylene by using heat to rearrange the polymers.

Polypropylene can be changed by heat. Heat breaks the bonds of the atoms, they rearrange, then bond back together in a different order creating a different type of plastic.

Blending the Two Types of Physical Science

The two types of physical science topics often overlap. For example, if a group of scientists use a laser to vibrate a single water molecule to observe how the oxygen and hydrogen atoms break apart. They are looking at both the chemical system of the water molecule and learning about how and where the individual atoms move in time. This is a matter of physics. These scientists are therefore studying both chemistry and physics at the same time.

Here are some physical science examples. Try to guess if each is a type of chemistry or physics.

• Digestion
• Roller coasters
• How a camera works
• Seat belts
• Leaves changing colors in the fall
• Metal turning to rust
• Using tools
• Apples turning brown when cut
• Photosynthesis
• Rainbows
• Hearing
• Meat or milk spoiling

Roller coasters and seatbelts deal with motion and are therefore in the field of physics. Tools such as a screwdriver, wrench, and hammer are used to make work easier. They all apply a force and cause motion and are therefore considered a type of physics. The traveling of sound waves and light waves is physics as well, so rainbows and hearing are included here too. Light is also refracted by lenses in a process called refraction to create the images. The human eye also works similarly to a camera and would therefore be included here as well.

Meat or milk spoiling and apples turning brown are a matter of chemistry. Oxygen is a factor in many chemical reactions and spoiling food is due to exposure to oxygen. Metal turning to rust is also due to oxygen playing a role in a chemical reaction. When plants undergo the process of photosynthesis, water and carbon dioxide molecules dissolve their bonds and rearrange into glucose and oxygen molecules. This is a chemical reaction and therefore falls under the branch of chemistry. Digestion is similar to photosynthesis in that food molecules are being broken down into smaller molecules that the body can use. Leaves turning color in the fall are also due to a chemical reaction. When the temperatures get cooler, the green pigment called chlorophyll breaks down and leaves lose the green color, and the other pigments in the leaf show through instead.