Physical and Chemical Change
By: Josh S.
A chemical change is something that changes the composition of a material. This can create gas, a change in color or rust. All of these things are chemical changes. Precipitation can cause chemical reactions. When it reacts with iron it can create rust. This process is known and oxidation. Exothermic (give off heat) and endothermic (absorb heat) reactions are also chemical changes. An example of an exothermic reaction is a match. As it gives off heat, it changes chemical composition. An example of an endothermic reaction is a plant. As the plant takes in heat or light, it changes it's chemical composition into food.
A physical change is a little more basic. A paper ripping or an ice cube melting is a physical change. In both of those examples the chemical composition doesn't change. The paper is still paper and the water is still H2O like when it was in the solid form. A physical reaction is very simple and results with the substance having the same composition before and after.
What is the Same
Both of these result in some sort of change that is different than before. Whether it be small or large, a change occurs. They also both can result in bad things or good things. For example the popsicle was made through an accidental physical change but when 2 substances react chemically, the change can result in an explosion.
What is Different
The 2 are also very different. While one changes appearance, the other can change the chemical properties. They use very different methods to cause change as well. While a physical change can take a long tim to occur, a chemical change can happen very quickly.