Useful tasks, making a change

Lifting, hauling, lighting, warming

Consider a range of examples of tasks that make a change. You can make changes by:

• lifting(by hand, by electrical motor, using something else falling)
• hauling(by hand, by combustion engine, by electrical motor)
• warming(by hand, electrically)
• lighting (chemically - candles or gas, electrically)

You can use different technologies and make trade-off choices for each technology about how to make the change.

In each case, make the change clear by describing a snapshot that captures the situation before, and another that captures the situation after.