Engineering Explained is a great YouTube channel that loves digging into the automotive side of science. This time, he's turning his attention to the engine, and he's brought a thermal camera along for the ride.
OK, maybe there isn't actually a ride involved. Instead, EE digs into the science of a warming engine. His thermal camera points under the hood of his, and we get to see just which parts of the engine warm up first after a start in brisk 22-degree F weather.
The video doesn't solve the age-old question of whether or not you need to warm your engine all the way up before driving in winter (I'm in the "no" camp, for a variety of reasons), but it does show that the oil filter and alternator heat up well ahead of, say, a battery.