The goal of the instruction and cumulative experiences in this unit is for students to build a concept of what makes a thing a computer. Students think about how tools and devices can be helpful for completing tasks. Students are able, from everyday exposure, to differentiate devices that need a power source and those that do not. Within the class of devices that need a power source, students can form a further classification of electronic devices—ones that do something with information that is put into the device. Upon recognizing input-processing-output characteristics of devices, students can also begin to classify and use devices for different purposes, including playing games, communicating, and doing schoolwork.