Raisins swell up after being placed in a beaker containing water for some time because:

Raisins swell up when placed in water.

Two beaker contain hot water of the same temperature one beaker is placed in anotehr beaker containing cold water and the other breaker in fornt of a rotating fan .It is observed that the beaker placed infront fan cools faster .explain the reason

A small piece of aluminium metal was placed in a beaker containing a greenish solution. After some time a grey coating was observed on the aluminium piece. The greenish solution is most likely to be:

5 dry raisins were placed in each of the two beakers containing 50 mL of water. After four hours, the raisins were taken out and wiped. For calculating the percentage of water absorbed by raisins, the raisins should have been weighed: