Use your finger to test for any liquid on the outside of each canister. Expected results: More moisture appears on the outside of the film canister that is placed under the cup with a lot of water vapor in it. The film canister under the cup with the dry classroom air has less moisture on it.
Technical knowledge is a theoretical ability to face a technical problem, analyze it, describe it, solve it, talk about it. Commonly found in teachers and drawing table engineers. Technical skill is the practical ability to execute the above.
For experienced, good technical knowledge would mean that one should have some level of expertise in the technology that he or she has worked in. Also one should be aware of the advancements in that particular area/technology.