Chemistry is often called the central science because it connects physics, mathematics, biology, medicine, and the earth and environmental sciences.Hormones are chemicals that help us grow, heal, sense the world around us, and find love. Soaps and detergents act as emulsifiers that surround dirt and grime so it can be washed away from clothing, dishes, and our bodies. Fire is combustion, which is a chemical reaction. It cooks food, heats homes, and runs vehicles.