* Acquire an apple core remover.
* Use it to punch out a potato cylinder.
* Weigh the cylinder and keep it at a hot place for some days.
* Reweigh it until there is no more loss in weight.
Observations: The potato shrinks very much.
                            The fresh potato chip had a mass of .......... (6.8) g,
                            The dried up potato chip had a mass of .....(1.4) g,
* Explanation:  Three quarters of the potato have been water.