[Music] hi it's Mr Anderson and this is environmental Sciences video 22 it's on energy Concepts I was just wondering how much energy it takes to do a Google Search and so what did I do of course I did a Google search how much energy does it require and what you get really quickly fourth one down is a document from Google themselves and they said that a typical Google search takes .2 seconds and requires 003 kilowatt hours so that's fast but I don't know how much energy that is and so we can use energy Concepts to figure that out so that's the energy and I want to convert it to something that I actually know so how much time could we run a light bulb a 60 wat light bulb in the same amount of energy so I'm going to take the known quantity from Google I'm doing dimensional analysis so I always put this over one and then I'm going to look up a conversion because we know that one kilowatt hour going to put that on the bottom is equal to 3.6 million jewles of energy that's just a conversion between two forms of energy and so what I'm doing is I'm canceling out the kilowatt hours and now I've converted it to jewels that seems like a lot of jewels at this point and now I have to convert that to seconds well I know that a watt is equal to a jewel per second and so 60 watts is 60 jewles per second so I can cancel out my jewels and now I just multiply everything across the top divided by everything on the bottom and I get 18 seconds now if that seems hard hopefully as I've gone through this video at the end you could solve a similar problem but what does it mean one Google search is the same as turning that light on for 18 seconds and to me that seems like a lot of energy 18 seconds isn't that long but it seems like a long time so I'm not going to wait that long so if we look at what energy is energy is the ability to do work or transfer heat you probably learned this before it comes in two forms we have potential energy which is due to position and then we have kinetic energy which is due to motion and so chemical energy so the energy in a fuel for example is potential energy it's energy in the bonds of the chemical and then something that's really important electricity is actually a form of kinetic energy energy is conserved it can neither be created nor destroyed and that's the first law of thermodynamics and the second law of Thermodynamics you should become familiar with and that's idea that as we convert energy from one form to another we lose energy that eventually becomes heat and increases the randomness of the universe or the entry of the universe the unit of energy is the jewel but you're going to find tons of different units out there from the kogle to the btu to the therm and the hard part is that you're going to have to make conversions between those different forms and if you have a really good grasp a dimensional analysis is really not that hard power is the amount of energy that we use for a given period of time so it's the rate of energy use we measure that in watts and one jw/ second is equal to 1 watt now you'll also see Kil kows a lot of the time and that's going to be a th000 watts and so energy remember can be potential or kinetic so if we take this crate and we lift it up it now has potential energy it has gravitational potential energy and as we drop it it releases some of that energy as kinetic energy now that box itself still has potential energy it has energy in the bonds we call that chemical energy that could release that by for example burning it another type of kinetic energy that's really important is going to be Electric some motion of those electrons the key point is that energy is conserved that's the first law of thermodynamics so if we drive this car from point A to point B we used energy we did work on that car now where did it come from gasoline but before that it was in the oil before that it was probably in some kind of a tree before that it was in the Sun so we're just converting one form of energy to another the second law of Thermodynamics talks about what happens to that energy as we do these conversions and so we've got input energy and then we're going to have output energy some of that's going to be useful energy in the motion of the car but a lot of it's going to be waste energy it's going to be heat it's going to be sound and eventually what happens is all of that energy becomes nonusable or heat the first person to really figured this out was James Jewel what he did is had a apparatus where he had paddles inside water he would have a weight that fell and as they spin they heat up the water you can measure that with the temperature that's why we call it the jewel capital J another way to think about it is it's the force times the distance and so imagine you take an apple an apple has a gravitational force of around 1 Newton and you lift it one meter that's one Jewel of energy required to do that now you can move it slow or you could move it fast but if you move at that distance that's going to be one Jewel how do we tell the difference between moving it fast and slow that's going to be power and we measure that in Watts that's the amount of jewels for a given period of time so let's say it takes me 2 seconds to lift that Apple 1 meter so how many Jews is that well it's still 1 meter * 1 Newton so one Jewel since it two took 2 seconds that's going to be 0.5 Watts what if I lift it in 1 second that'd be one watt what if I lift it in a half a second that's going to be two watts and so the amount of power in a 60 wat light bulb would be like lifting that apple in 0167 second so it's really really huge amount of energy and so there are lots of different forms of energy that we have so to convert between these two you have to know the conversion it's not something you should memorize but you should be able to look it up so one jewel is what we measure it's our base standard SI unit of energy if we have a th Jewels that's a kogel when we're talking about food or the energy found within our food you'll see calories and kilo calories one calorie is 4.184 Jews but the actual calorie we we're talking about in our food is is a kilo calorie and so one kilo calorie is going to have 4,184 jewles you'll also in see in some air conditioning and heating systems BTUs are British thermal units so we've got a conversion here to jewels we could use therms which are larger amount or we'd even talked about at the beginning these kilowatt hours all of these even though it has the term hour in it all of these are measures of energy it's because we're dividing our power by a certain amount of time when it comes to Watts it's a little simpler we've got a watt which is Jews per second and then we've got kilowatts as well and so you should understand these conversions I wouldn't memorize them but how to apply it in a problem and so let's say you're given a problem like this we've got a 75 watt light bulb how much energy would this use in a day in 24 hours if we left it on so you're going to start with your known so we've got a 75 wat light bulb so I'm going to put that 75 jewles per second you could pause the video now and try to solve this one on your own but let me show you how to do it uh I could work either on the energy side so I could go towards kogs or I could go towards hours I'm going to go towards kogs because I have a conversion up here I know how I can go between jewels and kogs and so I could write out that conversion I'm going to put jewels on the bottom kogs on the top so I've already moved from jewels to kogs you can see my Jewels had cancel I want to go from seconds to hours and so how do I do that well I know that 60 seconds is equal to 1 minute now my seconds cancel I could go from minute to hour so I know that 60 Minutes is 1 hour so I've got it all the way to kles per hour and how many hours does it run it's going to run for 24 hours so that's my last conversion so all my units will cancel and I'm going to be left with our with kogs at the end so I multiply across the top multiply across the bottom so it's going to be around 6,500 KJ with significant digits and so the best way to solve problems like this is to do problems like this and I'll put some links to problems in the video description down below but did you learn the following could you pause the video at this point and try to answer what's in all the blanks so again energy is the ability to do work or also transfer heat it can be potential which is due to position or kinetic which is due to motion the unit is the jewel but we have all different types of jewels or rather energy forms that we can use um so you have to understand not only conversions but how to do the conversions um the watt is Jewels per second thermodynamics shows how energy is conserved we got the first and the second that's energy and I hope that was helpful [Music]