The highest level of scientific experiment is known as experimental, or randomized control. In this type, as the name implies, there is the greatest amount of control. There are at least two groups used in this type of scientific experiment. Each group is made up of subjects that resemble each other as close as possible, such as by age, gender, etc. Subjects can be human, animal or the environment.
Chemical changes can result from the combination of different substance through a reaction to give one or more different substances. Decomposition, the opposite of combination, involves the breakdown of a single substance into two or more different substances.
A chemical change is the change of one or more substances into other substances. A physical change is when the state or shape of matter is changed. In a chemical change molecu â¦ les are combined or beak apart to form new substances.Rusting iron is an example of a chemical change. crushing a can or tearing paper can be an example of physical change. 7 people found this useful.