Why do science experiments in class if thousands of people have done it before us and we know what the outcome should be? Every year in science classes around the world, we do science experiments to prove that what we write down in our notebooks actually occurs. Of course we know what to expect, but sometimes when we do little mistakes- the unexpected occurs and we learn from our mistakes and see a different chemical reaction of some sort. Every scientist does experiments to test new medicines or chemical reactions of some sort to understand what they should expect when certain chemicals are combined. We know that when combine hydrogen and oxygen, we create water of H2O. We can also see that when combine potassium and water- it is very dangerous and creates a mini explosion and sparks. We know to expect these certain reactions because scientists before us have tested them and shown us after many tries for validity, can prove that this reaction will happen when combining these chemicals. 


DNA which is deoxyribonucleic acid, is what every living organism consists of. Without DNA we would not be able to function as it is the carrier of all genetic information. DNA is always in a very distinct pattern consisting of nucleotides which contain a sugar molecule (deoxyribose), a phoasphate, and one base. There are four bases; adenine (A), guanine (G), thymine (T), and cytosine (C). When nucletodies pair up, adenine always pairs up with thymine and guanine with cytosine. You can expect that this will be true throughout the entire DNA strand if this is a "normal" DNA strand. When the unexpected happens like adenine pairing up with guanine, this is known as a mutation which can cause medical and mental illness or a disorder of neural development.