 Looks like we're ready to go for Lesson 1. Lesson 1 is energy and society. As we talked about, this lesson is going to teach us basically about energy. What is energy? And in which units we measure energy, commonly used units, and there are different forms of energy that we use. For example, we use electrical energy or mechanical energy, like moving a car, etc. And we need to know the units in which we measure these different forms of energy. So we'll learn about forms of energy. We'll learn about the units in which we measure these forms of energy. And also we will get into a very, very important distinction between energy and power. And you need to be very clear that is the key concept in this lesson that I want you to concentrate on. Power and energy. And once we know the difference, using power we can calculate energy, or if we know the energy and time we can calculate the power. So we will also look at some of those calculations. And once we know the power, we can calculate energy, as I said. So we are going to do some exercises, like for example, a computer consumes some power, at the rate at which energy is drawn. And if we use for so many hours, what is the energy consumption by this computer? And similarly, we can do for a refrigerator. We can do for any other appliance that you use at home. These are common appliances that we are using every day in life. So when we add up the energy consumed by computers, by toaster, by oven, by refrigerator, by lighting, et cetera at your place, you get basically energy consumption of all your equipment in a day. And we are going to do that and calculate energy consumption for a day and then for a month. And we can calculate also electric bill for one whole month. So that would be our objective in this lesson. Be careful again. The distinction between energy and power is a very important concept. Forms of energy and the units in which we measure energy are the things that we will be looking at in this wonderful chapter. All right, why wait? Let's go and start our chapter. Good luck.