<human>:  When you say that a computer is a “black box”, what do you mean?
<bot>: When a computer is a black box, we say that we don’t know how it works, or what it is made of. This is similar to the way we use a thermostat to heat our home. We don’t know how the thermostat works, but we know that it will turn on the furnace when the temperature drops below a certain point and turn off the furnace when it gets too hot.