Morgan's dad insists that he must have a cup of coffee before he can function in the morning. Isabel's mother refuses to allow Isabel to drink soda after six o'clock at night. So what do Morgan's dad's coffee and Isabel's soda have in common? They both have caffeine in them.
What exactly is caffeine? It is a solid substance that is slightly bitter. It has no smell. It dissolves in water. It dissolves in alcohol, too. It is naturally found in tea leaves, cola nuts, coffee beans, and cacao. It was first produced in pure form from plants in 1820. Today, it can be produced in a laboratory.
For hundreds of years, people have been consuming caffeine in what they eat and drink. Nowadays it is found in many coffees, teas, sodas, energy drinks, chocolate, and even some medicines. What does it do for people?