Energy efficiency and resources - Intro

Not one joule of energy is ever destroyed, in anything that happens, anywhere. Yet people talk about wasting energy all the time. Whole countries plan for the day their energy runs short.

Both of those are true at once. This chapter, Energy efficiency and resources, is where they fit together, and this video shows you where to begin.

If this is your first time through the topic, start with Conservation of energy and dissipation. It follows every joule of a change to where it ends up. The idea everything else in the chapter rests on is that the energy always ends up somewhere, and it is the one students miss most. Reducing unwanted energy transfers builds on that. It covers how lubrication, insulation and thicker walls cut the energy that goes where you don't want it. The thing to get right there is the direction insulation pushes the rate of energy transfer, because students often get it the wrong way round. If the sums are what worry you, go straight to Calculating efficiency. It works through each calculation one line at a time. Most marks there are lost by rushing the working, so that video takes every step on its own. Increasing efficiency is Higher tier only. If you sit Foundation, you can leave it out, because nothing after it in the chapter depends on it. The chapter ends on a pair about where our energy comes from. If that's the part you need, you can go to it after the first video, without the efficiency work in between. Energy resources and how we use them comes first. It sorts the resources and matches each one to its jobs. Saying what makes a resource renewable is the line students find hardest to put into words, and that video gives you the words. Reliability, environmental impact and the move away from fossil fuels then weighs those same resources against each other. The skill that matters there is answering the side the question asks about, reliability or the environment, and not the other one. So here is how the opening fits. Wasting energy means letting it spread out into the surroundings, where it does no useful job. Running short means using up the resources we get our useful energy from. The energy itself is never destroyed. Search for any of these by its title, or by the code beside it. The scholafly.com website is the fastest route, because it indexes every video in every subject.

Next in the chapter is Conservation of energy and dissipation. Hopefully that's next in your feed, but if not, search for ScholaFly P H oh six, oh one.

Every other video is on scholafly.com too, easy to search by video code or by keyword. Whatever you're revising, go there and have a look, or, watch the next video.