Guys, so a lot of times in physics, we're going to work with really long numbers whether they're really big or really small. For example, the mass of the Earth is a crazy long number here. Imagine we had to write this out every single time we used it. Well, fortunately, we can use a type of notation called scientific notation, and we use scientific notation to compress really long inconvenient numbers into much shorter ones. For example, we can take this long number here with a bunch of zeros, and we can rewrite the mass of the Earth as 5.97×1024 kilograms. So this is a much shorter way of representing that number. So, the general format for scientific notation is going to be a number a.bc×10d. a.bc is just going to be a number that's greater than or equal to 1, but less than 10, for example, 5.97. Then, that's the number, and you're going to multiply it by 10d. This d is just an exponent. So, how do we actually get all these numbers? I'm going to show you a really simple process for how we convert or how we rewrite standard form into scientific notation. Standard form is just normal numbers and then into scientific notation. Let's just do a bunch of examples so we get the hang of this. So, we're going to take this number and rewrite it in scientific notation. The first thing you're going to do is you're going to move the decimal place until you get to a number that's between or greater than or equal to 1, but less than 10. So here, the decimal place is over here, and we have to move it to the left. 1, 2, 3, 4, and then 5. So we're going to move it 5 decimal places to the left in order to land at this number 3.04. The next thing we want to do is round this number to the second decimal place if it's a really long number with a lot of non-zero numbers, like this one is. So we're going to take this and we're going to round it to the second decimal place. So we're going to have to look at the next digit over here, and it's greater than 5, so we're going to have to round it up. So, I'm going to round this up to 3.05, and I'm going to multiply it by 10, and now I have to figure out what the exponent is. Well, that's the 3rd step. The 3rd step is the number of decimal places that you moved in the first step is going to be equal to your exponent. And if you came from an original number that's greater than 10, that exponent is positive. So, for example, we moved from a number the original number greater than 10, we move 5 spaces to the left, so our exponent is positive 5. And that's how you rewrite this number. That's really all there is to it. Let's do a couple more examples so we get the hang of this. So now we're going to do the same thing over here. We now have to move the decimal place until we get a number that's between 1 and 10. So we actually have to shift it forward 2, 3, 4. So there were actually 4 spaces to the right that we moved here. So we end up with is a number that's 1.02, we don't have to round it or anything, times 10. And now, we have to figure out the exponent. Well, we came from an original number that was less than 1, so our exponent is negative. So it's 10-4. The 4 means the number of decimal places that we moved. And now you might also see some weird ones. You might also see, like, you might have to you know, your professor might ask you to represent 7 in terms of scientific notation. So we're going to follow the same exact steps. Move the decimal place until we get to a number that's between 1 and 10. But if you think about it, the decimal place is right here, and this odd number is already between 1 and 10. So the way you would write this is 7, you don't have to move it, times 10, and the number of decimal places is equal to your exponent. But you didn't actually move any decimal places, so this is just times 100. Just in case you see some weird stuff like this, this is actually how you would represent this in scientific notation. Alright. That's really all there is to it. And the next thing you might see, the other kinds of questions you might see, is you might actually have to go backwards. And what I mean by that is you might have to go from scientific notation out back into standard form. So you might have to rewrite scientific notation numbers as normal numbers. So let's get a few examples. I'm going to show you a really simple process for doing that too. So imagine we wanted to take this number here, and we want to write it as a normal number. Well, really all you're going to do here is the exponent is just going to be the number of decimal places that you moved, just as it was up above, and if the exponent is positive, your number becomes larger. If it's negative, it becomes smaller. So, for example, 5.45×108. This 8 here means move the decimal place. In order for the number to become larger, you're going to have to move it to the right. So 5.45, what you do is you take this number, and you're going to shift it to the right 8 times1, 2, 3, 4, 5, 6, 7, 8, and you're going to fill in 6 zeros over here. So this is how this number would be in standard form. And for this last one, 9.62×10-5. So what we're going to do is 9.62, and the exponent is the number of decimal places you'll move. And if the exponent is negative, your number becomes smaller, so you're going to have to shift to the left. So you're going to go 1, 2, 3, 4, 5, and then fill in your zeros. 1, 2, 3, and 4. Your decimal place ends up over here, and you're going to put another 0 there. So that means that this here is how you would expand the scientific notation back out to a normal number. Alright, guys. That's all there is to it.