Attending closely to any one input of information usually reduces the ability to attend to others at the same time. Learning often results from two perceptions or actions occurring at about the same time. The more often the same combination occurs, the stronger the mental connection between them is likely to be. Occasionally, a single vivid experience will connect two things permanently in people's minds. Language and tools enable human beings to learn complicated and varied things from others.
Students establish three mini-aquariums in cups.
They put a goldfish in cup 1, a sprig of Elodea in cup 2 and nothing in cup 3. Students are asked to explain the change. Students then blow into a cup of water with BTB to witness the change from blue to green to yellow. Later on in the discussion, the teacher explains both fish and humans exhale carbon dioxide, producing an acid condition in the water. Toxic substances, some dietary habits, and some personal behavior may be bad for one's health.