hello ladies and gentlemen I'm Mr G and today we're going to be learn about mapping Earth what you need to have is what this goes along with is a guided notes packet um I have it as number 30 it says topographic maps you need that you'll fill it along as you go uh if you need to pause the video to fill in the information on the lines or label diagrams you need to do that so have your finger uh on the pause button as we go so here we go mapping Earth so at a basic level uh paper maps of Earth before there were phones and GPS and iPads with paper maps of Earth and as a matter of fact they are still very useful because a phone is only this little small thing you can't only see so much you're zooming in and zooming out but you have a big paper map that takes up a whole entire table you can see a large section of Earth and different maps have different um show different feur features of Earth on them and that's what we're really going to look at now so for instance on a phone or on a uh you know Google Maps or something it kind of just shows roads and businesses things like that but we are looking at maps that uh include um features of the land like the hills and the slopes and and things like that that are are not so much man-made features but more the natural featur so you'll get a sense as we go so here is a typical sort of topographic map as you see I don't know if you can see the different colors in here a lot of green on there that represents sort of vegetation uh think of forest or wood so let me just zoom in so maybe you can see it a little bit better so for instance what this is showing is it's probably a little light green right there and this is a called Flat Iron Mountain wherever this is and it has these Brown lines and these they have these interesting looking circular lines and that shows elevation how high it is um how high the land is and they compare it to sea level the level of the ocean CU that's very uh consistent so for instance this line right here is 4,200 ft above sea level this is all going downhill so that's 3,200 so this is going downhill and then uh this is going to the top of the mountain this represents sort of the top of the mountain the round circle um and we're going to get into some features of this but this is what I mean by a topographic map these lines are called um contour lines or isol lines so let's keep going with this so some basic things not a huge amount of definitions but pause this and copy this down now please okay if those are contour lines the Contour intervals are what the lines count by okay what each one of those brown lines count by and it varies different maps are different uh have different Contour intervals so for instance um this map here I hope you can see this down here this is actually in meters so whether it's in feet or meters matter mostly in the US we're going to see it in feet but some they give you meters it says 50 MERS so each line counts by 50 m so that's 500 m above sea level and they go a meter is about 3 feet a meter is about this long that doesn't matter so much for this but so where can we really see that so for instance that's 250 m above sea level and then that's 500 so each one counts by 50 so it's 250 300 350 400 450 500 and this line will be 550 M that'd be 600 M so also notice that usually every Fifth Line is darker and usually labeled somewhere that really helps or else just be a weird jumble of lines so um the darker lines help us as well so for instance this is a real map and real um uh you call USGS topographic maps in the United States they will always say they have a very um consistent format it will say Contra interval in this case is 10 ft each line on that map counts by 10 ft always start with a map by looking at what the contour interval is because you because it does vary between different maps please copy this stuff down now pause it okay A Benchmark is a specific location where we measured the exact elevation usually years ago it shows the exact elevation of a specific spot often to the individual foot so for instance this is an example you see on a map uh BM means Benchmark through 324 that means the elevation is exactly 324 ft in that spot now what does that look like on a map itself this is a real map of an area um in Upstate New York this intersection here it has BM has a x so right there BMX says 304 so that's 304 ft above sea level and you'll be able to go what they do the people who measure this they will actually put a metal disc in the ground they cement it into the ground and they will Mark 304 ft on there so that people can measure to that and then if you're 10 feet above it you're 314 feet above sea level for instance that that's why they do it so it looks like this there are these like a brass or bronze disc this one say 103t and they're about this big and just to give you a sense of scale that is me in my bearded days taking a picture with a um Benchmark marker right there see it's got a little green over time but it's about this big and it is cemented and you want to put it somewhere where it's not going to change want to put it in a tree and then the tree grows or falls down so it's usually like cemented into Solid Rock somewhere that's a benchmark okay next up I have this we have this please copy this down for gradient so gradient is a term that we use for a lot of different um uh variables in science but let's just focus on uh maps for now for maps by gradient mean slope of the land High gradient means steep slope and low gradient means gradual slope so for instance if this is a profile of a mountain here right um between the two red lines right that we have the pretty high gradient it's pretty steep right here so we between the red but yet between uh between the two blue lines right here it's much U flatter more gradual so it's a lower gradient uh more more gradual slope is what we say and we want to measure these numbers I always say in the world of science we want to quantify things quantify and think of what word is in quantify a quantity put a number on it right that's what we do in science we want to get data we want to measure variables in signs put numbers on them so we can compare them that's why if you go outside and there's the weather you say what's the temperature you don't say hot or cold or cool we really want to get into a number and we use Fahrenheit and Celsius and it is 74 degre or it's 32° something like that so that's what grading does is going to give us a a number um for how much the land the slope of the land changes next up is profile so please copy that down and a profile is a side view so what we were just looking at here uh this right here is the profile of um this mountain side view of it we'll be drawing those actually you'll be drawing those which actually is pretty cool students usually like it so let's let's keep going so for instance please pause it and copy these two words down so we're doing two things here uh we're looking at two things so we're looking at a profile view of a mountain and then the map view so this is showing the isoline view so for instance I I really like this to help right notice how steep the slope is here and it's much more gradual here so if you drew these lines 100 ft 200 one cont interval here would be 100 feet you drew these lines here and you drew a line where everywhere in that line is 200 feet above sea level it would look like this line right here that's what this line is okay so this is the topographic map view and this is the profile view we we will be taking a map view and you will be able to use a pencil scrap paper and draw this which is cool but one key thing where the um slope is steepest notice the contour lines are really close together and whereas more gradual slope they're further apart that is key make sure you know it okay some rules of Contour Lin so uh you'll be drawing these we call them isol lines CU um they can be used for a lot of different variables a lot of weather variables temperature and air pressure and you know depths of lakes things like that but for us for maps when talk elevation we tend to call them contour lines so some of the rules are contour lines can never touch or cross each other I'll get to that in a second and lines are read the closed circles are run off the map they can never just end okay you never just end and that's something you learn as you're drawing them so here's an example of what I'm saying so let's say this is the 450 ft contour line right here and this is the 400 ft well so this is breaking the rule you cannot do this because here they cross because what can't happen is that can't be both 450 ft above sea level and 400 feet we can't be if you ask a kid a kid in class how old are you you can't say I'm 14 years old and 16 years old can't be right you can't weigh 152 lbs and 177 PBS at the same time can't be so uh they cannot do this they can't cross they can get really close to each other when it's really steep but they can't touch or cross so another rule here is the closer the lines the steeper the slope of the land so please pause this and write this stuff in all right so what you're seeing here this is a mountain this is a more gradual slope because they're further apart this is the steeper slope of this little maybe probably more of a hill it's only 75 feet above sea level see count interval is 5T so that's interesting here and we need to know that because here's a question that we have on here uh let me dismiss that a possible elevation of point x what is a possible elevation of point x so see if you can do that now if you can't wait and I'll show it to you okay hopefully you got an answer for that so if this is 50 ft and 7 they count by five right so 50 55 60 65 70 75 so I got to figure out where this is this is here this is the 50 goes around so 50 that line is 60 that Line's 65 well that's in between so it's not on the it's not on the 55 or it's not on the 60 so you can't say 55 can't say 60 or else the dot would be on one of those lines it has to be between those so any of these answers would work and this this is kind of um so any of these if you see what I wrote In Here 50 6 ft 57 58 or 59 if you wrote one of those you got it correct good job if you didn't hopefully you can see why it is uh any of those four answers okay let's keep going here we go Stream flow so this is another rule of cont line Stream flow when Contra lines cross the stream they form a V and the V points uphill please pause it and copy that down now the V Point uphill so the pointy part of the V points uphill this tends to drive kids crazy a little bit but you will get this don't worry so in this case you have fish creek and I show the flow Direction it is Flowing out of the lake and then what I did is when it when any sort of river or stream crosses contr lines it forms a v the V points uphill right the kids kids really want they want the pointing to point the direction of kills it'd be so easy right like an arrow it'd be so easy but it's actually the opposite and this is because Rivers as they flow over many many years they carve and they erode a valley a valley and just by the nature of how contour lines work the V ends a point Upstream so often times we want to know what direction the stream flows stream flows this way V's Point uphill so in this case Fish Creek flows towards the east if this is north south east and west what direction does it flow let's do another example okay Mud Creek flows toward what direction so I did so what they what they gave in this in this diagram here was a question they gave just a North Arrow now what you need to know is and they expect you to know it so I want you to learn it now um in our Compass rows that ways North that that ways south East is that way west is that way and almost all the maps that we'll see pretty much every map we'll see um in school has is oriented this way so so North is is that way south is that way East and West so in this case Mud Creek uh Mud Creek is right here this is the ocean so let's see right look at the v's here the creek is Flowing that way the v's Point uphill so it has to be flowing the opposite direction therefore Mud Creek flows towards the southeast please pause this and copy that stuff down now okay another part of contour maps that they have to deal with once in a while not that common is what happens if you have we're used to having a top of a hill go like this what if you have like a bow shape the land makes a bowl shape how are you going to show that and it's a little ch in not that much of a of a big deal Us in the Northeast where we live because usually if there's a bll shaped land it has filled up with water it's a lake or a pond but it happens sometimes and so what they so they want to show these circles here are off the top of a mountain but in but instead they're a depression the land goes down again like a bowl shape uh they show these little like hair like lines in there so for instance and I like how this is drawn you see this here how it kind of goes up and it has this like depression in there this bowl like it goes down so how they show it here is this is 200 a 290 line right there so then this is showing it's going up 280 290 300 then it's going back down so it's showing the part of the hole so it has these little H hash marks in there the little lines 300 and 200 showing in there so be aware of that do some mapping practice and you'll be able to put this to use so what we're going to do here we're back to this uh same little Hill here steeper here more gradual here and then we're going to to calculate gradient because like I said before we want to quantify things in science we don't want to say oh that land that Mountain's really steep it's kind of steep it's flattish we don't want to say that we want numbers to compare science is always quantifying things so in this case Contra intervals 5 feet elevation is feet and then this is showing distance and you would use this piece of scrap paper in order to show that now that's a little challenging for me to do on this board because it acts all weird so I'm going to do my best please pause it and copy this down okay gradient like I said before for Contra Master is how steep the land is now there is a Formula it is on the earth science reference table it is the change in field value divided by distance a lot of kids don't like that what's up field value why don't you why aren we more clear it's a it's a pretty broad uh gradient formula that we can use for a lot of different variables but the field of values whatever you're measuring on Maps we're measuring elevation and this the distance is this scale so the elevation is this and the distance is sort of this way so we'll get a sense by doing this so for instance if I drew this side of a hill here A to B the change in field value is going to be elevation well B is at 200 and a is at 500 so 500- 200 500 - 200 is 300 would be the change in field value here 500- 300t change in field value and then the distance between them is this way I have it here so the distance would be this okay and the only way you really can measure that is if you have some sort of scale down here to to hold a piece of paper up to to mark it which we have on our examples so I just wanted to show that so here we go look at the first one here calculate the gradient between A and D where's where's oh a is here and D is there so what I usually encourage people to do this is the front page of the um earth science reference table the gradient formula is here it's given to you don't have to memorize that which is nice change in field value divided by distance and usually write that down to help you with that write that down that really helps the kids who don't do it tend to make simple mistakes change in field value divided by distance so a if they count by 5et a is that's 50 55 a is at 60 feet and then that's 60 65 d is at 70 ft so it's 7 so it's 70 ft minus 60 ft and then the well I'll show you that in a second to get the distance I won't be able to do that what you do is you will hold your paper up to up to the page like this oh see it goes crazy man it goes crazy hold your paper up to here and you mark a and you Mark D and then you hold it up to your scale right there and then you measure how far it is if that's one mile so it's 0.1 Point 2 3 point 45 miles you do that you really need to get practice on paper doing this hard for me to do on this board as you saw the thing just freaked out so what we have here the changing field value is 70 minus uh 70 ft- 60 feet 10 feet the distance is you should have gotten 02 miles right so then you do 10 on a calculator you type in 10 hit divided by 0.2 and hit equals and then you will get 50 ft per mile so what that means is if you're going this way you're going uphill for every mile you travel this Direction your elevation is gaining is Rising by 50 ft so we're putting a number on the gradient let's do another one number two says calculate theg gradient between c and e c is there e is there change in field value well e is right on the 50 line and you you can do it like this actually you want they count by five so then you can just do five 10 15 If You Can Count by Five So it's 15 ft is the change in field value right so uh that's uh 60 and you do it this way to 65 - 50 15 ft and then the distance if you put a piece of paper up there and you mark that and Mark that ho it here it's 8 Miles and then what you get is 15t so in the calculator 15 divided by sign 0.8 you hit equals and you will get 18.8 fet per mile and I rounded that to one decimal to the nearest 10th one decimal place but um and that means again so now this is not as steep every mile you travel this direction this direction you will then change elevation 18.8 ft about 19 ft number three looks like this so number three um B and F so the change in field value again you could just do it 5 10 15 20 or I did it this way another way to do it 65 - 45 20 feet and this distance is 1.4 miles so 20 feet divided by 1.4 miles you get about 14.3 ft per mile when that's rounded to the nearest 10 hope this is making sense uh there is one more [Music] remaining and it goes like this so what do we got uh what is this g& H so g& H here the change of fail is 15 ft but they're not that far apart 04 miles 37.5 ft per mile and the real reason you want this is if you're hiking or often times if it's a road you're driving a vehicle how steep is the road how steep is this hiking trail uh because if you're if you're hiking and you're carrying a big pack you want to get a sense of how steep that is and if you're driving a vehicle and maybe you're towing some sort of trailer or your or your vehicle really large can make it up that grade is is the word that they would use so one of the uh uses of gradient