This document discusses batteries and appliances that use batteries. It explains that batteries store electricity and can be inserted into appliances to power them without being plugged in. Batteries come in different sizes and shapes and each appliance requires the correct type of battery. The document emphasizes that batteries must be inserted into appliances properly, with the positive (+) and negative (-) ends in the right orientation, for the appliance to work. A torch is given as an example appliance that uses batteries to power a light bulb.