Q1.
What do you infer? Is this activity enough to come to the conclusion that water does not seep through a steel plate?
Answer
Inference: the water on the steel plate slowly becomes a smaller and smaller patch and finally disappears completely, while the underside of the plate remains perfectly dry the whole time. So the water did not pass through the steel.
Is the activity enough? Yes, for this particular question — and here is why it is a good test:
- Steel has no pores. Anything that seeped through would have to appear on the other side, and we watched that side at regular intervals.
- Nothing was placed below to soak up water, so a leak could not have been hidden.
But be careful about what you conclude: the activity proves that water does not seep through steel. It does not, by itself, prove that evaporation is the reason for the disappearance — it only removes the other possibility. To be fully sure we should also repeat it with a covered plate, where the vapour cannot escape. Much less water disappears then, and that is what pins the disappearance on evaporation.
Tip: Put the same amount of water on a dry earthen saucer as well. There the underside does become damp, because clay is porous. Comparing the two makes the role of the surface very clear.