
The process by which water evaporates and turns into water vapor is actually a form of solar energy and it can be harnessed and used to power small machines. The team is using bacteria spores that are by nature great at absorbing water. When they absorb water, they swell and when they lose water, they contract, and they can do this repeatedly without breaking down. This movement, like that of a small muscle is what is being used by the team to power small engines.