Probably more accurate to say that steam produced under the lid will tend to condense on the underside of the lid and eventually run down back into the pot. It is transferring some heat to the lid in doing this, but the lid can’t radiate heat away as quickly as steam can take it away when it drifts off.

Plus ski helmets with airflow vents usually have a way to close them with a little sliding switch, so you can get more airflow on a warm day but cut it off on a colder day.

Early season snowfall is the thing that will reduce their population over winter. Ticks need to fall onto bare ground after their last blood meal in the Fall. Being covered in snow after that insulated them from the worst of the cold. If they feed and then fall onto early season snowpack they won’t survive.

The units someone uses are ultimately going to depend on what they need them for. Someone working sending interplanetary radio signals might find light-minutes most useful, while someone studying orbits may likely use AU’s. If you’re trying to describe the size of orbits, using the orbit of Earth as a reference is really useful because it’s a distance that’s easy to compare to. It’s the same reason you don’t describe your weight in tones, differences of a few pounds are hard to conceptualize using units that are many times larger/smaller than what you can conceive.

Another “problem” with bear canisters, is that bears have really great smell. It may not ben that they can smell food through an air-tight container, but the container itself likely has trace amounts of food smell on the outside that got there as you handle it. As u/Volcan_R said, the idea is to make the food too hard to get, so the bear decides to put its effort elsewhere. So wether it’s hung from a tree, in a bear box, or behind an electric fence, (Yes such a product exists) even if the bear can smell it, it will decide it can’t get to it and learn to just move on.