hey welcome to the second part of this three part video series about question one in paper tree okay so in this video i will talk to you about plotting graphs and generally what and how your graphs will be marked by an examiner okay so in the previous video if you've not watched it please go watch the previous video okay um we have uh talk about generally the first 10 mark allocation which is the tables plus minus the fuel the preliminary reading okay so here you can see that um we are moving on from our marks moving on towards the bottom part of the table okay so that would be plotting your graphs so there's three marks here i will show you where the marks are according to the mark skin very soon okay so we're talking about mainly these two la these five marks okay so when you draw a graph right to score these three marks um there is axis plotting okay and also the quality of your graph all right so just let's run through the mark scheme together okay all the max games for paper tree especially this part is fairly consistent or in other words should be about the same for every single graph okay so number one axis we have to have sensible scales now what on earth is sensible skills or when you think about it right sensible scales are if you are a bit lost and you always confusion on how to have your skills in place i would suggest that you follow the one two five okay so the so-called one two five rule is like this your graphs the scale should either be in increments of so this one one two three four dot dot dot okay two four six eight okay one two five rule five uh fifth ten fifteen twenty i mean so about ten 20 30 40 that will be the one two three four zero point one zero point two zero point three zero point four okay uh twenty forty sixty eighty five hundred one thousand one thousand five two thousand okay of course this is you can add or subtract a prefix generally if we don't see this we are immediately suspect okay so uh other two there are two other scales which is in the kinda still okay not that bad but i don't recommend territory that would be the uh 20 25 50 35 zone okay so you could also he generally we don't recommend this the 4 8 12 16 don't recommend but if you put your graph right it's not that bad or the 25 50 7500 okay so try to try to stick to these three because it's easier for you to play you can save you some time but if you if for some real reason your graph cannot fulfill the other criterias you can consider these two okay do not have fractions or weird weird things happening on your xsr only this variation is accepted of course again with prefix okay so generally right the plotted point must occupy at least half the gradient of the graph sorry half the area of the graph okay so you whatever scale you choose it has to be at least half if there's no half then uh we will reserve the right to take away your maxima okay and the second part right that is also important is that you have to label the quantity the scale must be labeled and then the quantity that is being plotted so this label here includes units okay label this one is with unit okay and then the scale marking my suggestion is every 2cm you do one scale marking okay basically you can 4cm they still accept 6cm is out and the thing here is if you make any of this mistake there are four here the mark is gone you can label your axis minus one mark it's the same mach law you don't label your x's didn't include units in your label scale very weird graph too small the marking is too far apart or that lah you will lose this one mark or you could say this wheeler they penalize you one time okay for the axis all right next plotting i should expect to see six points if your table got seven points because you're an overachiever then uh please plot seven points because all observation on the table must be plotted if if you feel that oh i'm doing eight reading but now i want to see which one fit my line and then after that i want to remove the eight reading then but then make sure you remove it from your table whatever i see on the table i expect to see on the graph okay so um must be plotted the diameter of the plotted point must be less than or equal to half a small square so basically generally speaking your crosses have to be small how small okay this one is okay so if this is your graph grid the cross cannot you know with a pen it's a bit hard the cross cannot be bigger than the size of one box okay so this one is fine i mean it looks about the same so about the size of one box all right so it's going to go back here now okay so that's done uh plotted within the accuracy of half a small square so the thing is this accuracy of half a small square means you have to plot at corner only okay so what i mean by corner values right it's like let's say for example this is your graph grid at the back okay so you can plot here not problem you can plot here no problem this one all is okay not okay would be like this you plot here lah you plot here la or the in between or even worse you plot right in the center like this this one all not okay you might be telling or arguing or thinking but half a small square mommies maybe this is one maybe on my scale let's see this is my scale maybe here is one maybe here is two and my reading is 1.5 why can't i plot needle how sure are you your middle is really really the actual middle don't forget these boxes are very smaller you cannot be sure where your cross is the real middle so if that is the case when you have a reading of 1.5 you should round it to 2. if you have a reading of 2.2 you should round down to 2. okay all right so let's say 3.7 you run up to 4. four point two you round down to four okay that is if your scale is one per small box okay so later i will mark the graph and then you hopefully that will give you a better idea okay so all points so if you plot all these points correctly you get one mark so let's plot quality okay if you want to get this mark you should plot you should plot at least five points out of six if not this one is automatic zero okay um trends on the point have to be positive so this one depends on the graph so we are going to look at the trend you know remember just now when we talk about the table there's a certain trend so we will look at a trend to get this quality mark trend and generally is about plus minus 1 cm from the line so the values should be about 1 cm from the line but every year this number is different it depends on how stable the reading is but during the actual paper right what will happen is that you will have a lecturer conducting the exact same experiment as you will be doing and the cie or cambridge will take into account that lecturers result so if the lecturer's result is not nice then they might actually increase this number this one depending on who is marking and what's happening that year and what experiment we're talking about uh bad news for you whenever we do the experiment especially when i do the experiment the line is perfect if not i won't i won't i will keep doing like i will fix i will adjust until i get a nice light okay so you should also try la all right within the reasonable time frame use the please use the six or seven times you have to try to practice that okay next line of best fits so this three marks uh is just for the plotting of graph okay so line of best fit uh the line have to be balanced again later we will look through uh a few sample scripts so when we say balance or it means that um the number of points above and below the line must be the same okay again if you don't if you plot less than five points this mark you won't be given so you can see you tend to lose a lot of marks if you don't plot your graph but why wouldn't you all right so um one anomalous point is allowed if clearly indicated so if you're going to use an anomalous point please indicate clearly okay so you circle the anomalous point and then you label a normal list okay meaning when you draw your straight line or when i judge your best fit line i won't account for the anomalous point but you might be thinking miss if i have anomalous point this quality mark i will lose one mark already right probably can but it really still depends maybe all your lines are still very close within like 1 mm from your points are 1 mm from the line and you only have that one anomalous point which is 1 cm from the line then you can still get your quality mark but you can tell you can label that 1 cm point and say that oh this is the point that i'm not considering when i draw my best fit line okay line and then there must be at least five points left after so once again if you only plot five points and one of the five points is anomalous you will also lose this point now basically just draw your six points now don't give yourself headache okay lines must not be king means have confidence you slap your ruler on the graph paper you are just and then you draw you don't adjust already you draw halfway and then you go like yeah i think i should tilt my ruler then you tilt your ruler again then you draw your straight line will not be smooth it's a bit like committing to a marriage don't want no comment anyway have conviction when you draw your line adjust always have the kind of like half transparent half transparent ruler to help you adjust your best fit line practice practice makes perfect okay and please don't use a pencil that is very thick okay at most you 0.7 mm your left okay next gradient when we check your gradient this one has a lot of things to think about okay number one you cannot adjust the thickness okay number one when we talk about gradient we are going to look at a triangle if you never draw triangle immediately very nice i give you zero no triangle it's an automatic zero okay so number one is there a triangle number two is the hypotenuse of the triangle greater than half the length of the drawn line aka is your triangle big enough if you draw a long graph but your triangle is tiny then so much space for what utilize the whole paper okay and then on your graph ideally you should mark down your x and y coordinates on both end of your triangle okay so we will re you don't might never mind but marking will help the examiner so we will read the read read-off okay to see whether it's correct and then we must check the method now if you didn't write your method you didn't write the method and you by bylaw okay cannot all right so sine of the gradient on the answer must always match the graph if you have a negative gradient graph you should have a negative gradient if you have a positive gradient graph you should have a positive gradient okay it goes without saying the value they don't care so let's say you really mess up like your all your emitter reading is like 90 ampere then your graph of course your grading is going to be wrong but maybe it's not all you can still get mark you can still easily score full marks here because we will all we will acknowledge the fact that in front there's a mistake and then we will do that one mark from the front but here your method of calculation is based on whatever graph you draw for me even if your trend is wrong even if let's say you make a mistake and then you take all the reading wrong but i follow the graph so if the table you make a mistake marks is deducted at the table we won't deduct the same marks in your graph okay if the graph is wrong and mark's deducted at the graph we won't deduct the same marks in your calculation okay so that is the general trend you'll be penalized once for one mistake unless the mistake is very severe okay carry on like never right you need law that type okay anyway sign of the gradient must match okay can all right y-intercept so this one uh people always got problem one they like to read directly from the graph and that is only valid if the graph is plotted from the origin is this graph from the origin no you cannot read y intercept but the third is this graph from the origin yes then this is the y-intercept okay can i do another one is this graph from the origin nope pretty obvious so cannot okay and you get the idea so you read if you read off you read the intercept directly from the graph if the graph passes the origin okay so right here for you if the graph passes your zero zero okay if you're good in maths you might argue with me and say actually miss doesn't have to pass through y equal i mean y equal to zero but it needs to pass through x is equal to zero sure you can try but uh sometimes they put origin in the older mark scheme so i generally assume that the physics person marking my paper is not good in maths now if you're a person where no idea what i've spoken about for the past 30 seconds now mine now did you start from the origin no if you did not use y equal to m x plus c okay so when we use y equal to m x plus c you will substitute and equation substitute based on the graph given so this one you already calculated previously x and y is a coordinate on the graph so you pick a point on the line pick a point on the line all right okay so we will check the read off if let's say you take the point 10 comma 24 then i will check whether the line passed through the coordinate 10 comma 24. you want to label you don't want to label i leave it to you lah your question would be can i take the same read off as my gradient well you can the one two also cannot generally people don't do it but if you want to it's fine it can save you that half a second all right moving on let's max i was told from the second from the first video that i'm quite savage when locking really man nola it's not my true form far from that all right let's look at this candidate can you see a problem now okay i'm gonna move the camera a bit like a space so the first thing i notice uh from your script is this you know my friends where what's the label label missing so because you're plotting a graph of v against i it's the same the same table it's the same experiment so if you put a graph of v against i then then this one should be v over i okay uh bracket or comma sorry bracket or slash slash okay so what i should do is to go back to the table and look at the first candidate and check coordinate by coordinate did he or she plot prop correctly yes we check one every single thing we check why because it's our job okay are you doing your job are you writing your units are you plotting labeling your x's no i don't know okay so this one i'm gonna assume that the candidate plot correctly now uh generally i might choose a point to check okay i see a lot of problems with this scale like for example right this is 1.1 then this should be 1.0 correct where is the point zero went for a wall okay and generally this part here it should be labeled as zero like this this is zero and this one is 0.5 i do not understand uh what is what what what what is this what is this don't know i don't know okay so this is y one a shape that's like this by the way the candidate already lost the x it's smartphone labeling so all this extra mistake doesn't matter okay so uh whole toy good thing this one got plot okay second beef i mean the second complaint i have is that when you draw an excuse my friends you need an arrow there meaning this one i need to draw an arrow no arrow are very difficult you know difficult to operate all right so same thing here that i expect an arrow but i don't even know where the line ends okay so i've got a problem alright next we check the size horizontally one two so one two three four five six seven eight nine ten okay just nice horizontally just nice one two three four five six seven eight nine ten eleven sharp okay the size of this candidate is good is more than half okay uh the triangle is fine so the best fit line is also okay and this point is one two three four okay so all good so i'm just gonna write the marquee okay axis one mark uh innovate zero plot uh so that this doesn't become a two hour video i'm not gonna check the plotline okay so i'm assuming correct plot is correct what else uh axis plot quality this is a quality graph candle good enough and uh gradient triangle is big enough um this one is 0.9 this one like how how is this 1.5 this is not 1.5 1.5 is here see so if you're taking 0.9 this one should not be 1.5 it should be 1.57 so wrongly alone so this one should be 1.57 from a zero yeah do a check we'll check everything maybe i should just check the plot right i'm not going to flip back and forth okay next wow many calculates okay um you will notice for this candidate the decimal point is so tiny voila it's not like having it so please make sure that you know point can see now okay all right and then um let me check the values the values looks fine now um i'm quite strict one last examiner our deduct mark for this decimal point guys a similar point right here because this shows to me that you don't know how to label your axis okay so anyway even if i don't penalize for that one mark for axis there's one very obvious one i can penalize the graph is too thin okay okay so you can see uh this is one two three four one two three four five only five cm there 5 cm where got enough what happened only 5 cm 5 cm got enough not enough so 5 cm we need at least 10 cm so 5 big boxes so the graph is too small axis itself with a minus 1 mark x is 0 okay a plot okay let's look at the plot we got one two three four five six my friends you should not be good okay i can't really see that like this like this one here is this in the middle it looks like the middle to me so if it's in the middle we were minus one month okay la for the purpose of this example we shall assume this is in the middle cause too small so zero ouch quality um quality looks good so you can get one map here now gradient now if you look at the gradient on the triangle it's too small if the triangle is too small my life is very easy one i just give one mark i don't need to check read off i don't have to check whether he or she got substitute correctly or not i can just zero okay moving on next so the next one no you need lay io so no unit means x is zero but x is this resistance look very big okay see now here also got problem draw out one line like this draw out one line like this 14 draw another line here 50. okay um this one is okay one two three four five once i call the fish alive where is the six point oh there it is hiding here okay this is a corner this is not a corner plot okay you can see it's pretty obvious it's right in the middle so plot minus one map oh wait i've forgotten to give best fit line mark right five bucks right one two three one two three four five five this graph they didn't ask you to find the y intercept so i'm not going to grade it okay so this one is the best fit line best fit line will get one mark so this one is three out of five okay this one best fit is also okay so this will be two out of five this best fit looks okay to me too it looks balanced so this is one mark gradient is it big enough guys badly but okay la canela can so where's the reading oh oh you see a problem here [Music] not delta x delta y or delta y over delta x okay so it we expect to see something like this okay if not i cannot check your substitution you understand i cannot check whether you substitute the correct values if you do not show something like this and followed by this understand so i have to show this if not i cannot check your read off so i'm not obligated to give you that mark for gradient i mean this one's not good lah because you substitute the wrong value but this one even if correct also i cannot give ma so sorry okay moving on oh we have a good one in front i do not know man this plot is too big it's four boxes minus one magnet okay so let's see now you see i generally got problem with people labeling the axis here but what it's fine pen drop brb i'm back all right so ninth one this is not the best fit line guys i mean you got two points that are very far away below the line you got one point which is above the line but very close um i mean you're gonna be nicer than your second point but they're very close so that's not the best fit line okay so nevermind let's do one by one axis ladies and gentlemen axis here i the labeling is okay but one two three four five okay one two three four five vertically it's too small because vertically you have 12 cm so um i need six yeah six big boxes so one big box two big box three four five in fact i would argue it's four and a half so the graph is too small graph too small zero you see it's very easy to do smart because we look at a few criterions okay plot zero because the plot is too big a p q quality you know the point very far away zero best fit line not balance zero gradient i don't see a right angle triangle do you see a ringer triangle do you do you see a nope zero well ladies and gentlemen although we have not met our first five hour five we did meet our first zero out of five at zero by the way zero is my favorite number because in maths when you see zero your equation is very cute right the whole thing just disappeared zero will always be my favorite number okay so let's talk a little bit about the best fit liner one two three four five six okay um let's see if i can draw this digitally how how [Music] okay i will try okay no promises not sure how i'm gonna do this but can i just write okay so let's try and draw a best fit line [Music] um i'm guessing [Music] something you know whatever if you don't pass any lines right something like this is even better [Music] i'm not going to speed this up so you can see feel the real time let me see let me see let me see one two three one two plus one point okay maybe something like this because in this case right all the points are a lot more closer to the line so we care more about whether the points are closer to the line as compared to whether you pass more points make sense so in this one i have three on top and two below although this one is very far away so normally what you can do is you can label this one as anomalous if you label this one as anomalous then your line should be something like this label that one you know what if this candidate would have labeled this point as anomalous this one can stand as a best fit line ah well i should have would have could have next okay [Music] the dreaded zigzag line do not draw the zigzag line i don't know which school you come from do not draw the zigzag line you want to know why you cannot draw the zigzag line if you draw the zigzag line you are telling me for example on the the y axis you zigzag here this oh cannot use put what value is this is it one is it nine i don't know okay same thing all values here cannot use well you just wasted a lot of space like real estate very expensive these days especially in kl central so all this cannot use then while so i guess what i'm trying to say is don't do it don't zigzag because when you zigzag what will happen is let me draw out what i mean by that you can't use and all these two boxes anymore all these two boxes will be void and all these boxes will be void quite sad right so don't do this uh alright so do not zigzag what you should have what the candidate should have done is to do this i'm going to write this in great so it should look like this so this is 10 right so here should be 8 correct so you just draw this one out like this as 8 and then this one you draw down this is 50 60 so this is 40. okay that means uh between 50 to 40 here i know this one is 45. like between 10 and 8 here i know this one is 9. cannot put zero also not accepted okay so this is what should have happened so bye bye x is smart red color very harsh right okay i might be green plot is a bit too big so plot is zero quality canal can last close enough best fit line okay i'll see a nice big triangle fine i'm looking for working now uh okay so assuming you're taking you know what 50 and 15.8 i'm taking 50 okay this is 15.8 can 116 and 30. sure one one one five one one six okay one one six and 30. six okay great can looks good because everything is oh no oh no oh no by the way right now that is wrong you my point my point here is you see this is cm so this unit here should not be meter negative one it should be cm negative one if you want to change it to meter negative one then what you could have done is to bracket the cm here and times 10 to the negative two prefix ma okay miss would it affect my answer in this case no because at this point in time you did calculate the gradient correctly and generally at this point we don't check unit you wanna know where we check unit stay tuned for part three this is where we check the unit the last part of question one so three or five okay wow 38 minutes now come next much faster why really oh why oh wow what's happening here what is how is what i don't understand these lines like why what is this what is this what is this okay nevermind and what is all this what if it's part of your working when you plot the graph do not show rub it off okay because i'm assuming that you want to label this extra graph here but you didn't label here do not show all this uh the middle one what you should have shown is actually where 20 15 10 where all of these things are okay so i don't know what is happening here okay and i'm gonna assume here is zero is the zero 0.0125 at this one box in shouldn't it be here at the origin one two three four zero point two five zero point five again there's a zero here okay and what is this zero point five zero so weird like here's what i mean by weird let's say i give the candidate a benefit of darwin here to here is zero point one two five zero by one divided by zero point one to five zero point two five but hall here to here okay here is 0.25 there why nani did your scale just shrink or expanded okay so and then i've got a lot of problem lah all these weird marking that don't know come from where one [Music] so axis is a zero mark zero i also don't really know where the melee come from i will check the table okay uh plot zero number one we don't allow blocks okay so only cross and make sure your cross is around the size of one small box all right let's check out the quality [Music] quality assuming again yeah when your graph is like this so i'm assuming here you plot wrong one but good thing here you don't have lines because here to here is 0.25 here to here is 0.25 only here to here i don't know what is happening here what is happening here what what is this okay so yeah anyway [Music] sure quality is fine let's look at your best fit line bf best friend best fit all right buzzfeed is okay gradient [Music] where's your calculation for gradient candidate where's your angle triangle candidate you see here you draw two main lines i don't know whether angle triangle is here now i don't know what this line is for i don't know what this line is for i don't know what this line and this line help help a sister out only draw what is needed okay basically i should only see the line of the graph and the hypotenuse of the wrangle triangle and also her oh wait i forgot to comment one thing i always forget about this this one is very good because the triangle is dotted like this one no triangle this one very good triangle is dotted line this one uh although the green gate is zero the triangle should be dotted line because more stringent examiners will assume that the full line is your graph dotted line is what you are trying to represent i mean your gradient your triangle basically not your graph last oh your triangle have to be dotted line like this one should be dotted like granules wouldn't give mark already good thing we can only minus mark one time right this feels like a blood bath yeah this is why people lose smart in paper tree law because you know now you see at home you never do experiment i'm not marking your let me point in front of you i can't net you then night night night after a while whenever you draw a graph so you stress really like oh oh dotted line okay good this one no triangle gradient is zero i don't see working life it's on another page that it was not scanned i apologize but it's not shown in this page so two out of five moving on how many more one two oh two more very good very good okay let's look at oh good lord people do you see the problem here so far no more than three boxes but if you're my student i highly recommend no more than four four cm two big boxes that's all that's it no more cannot discuss not up for discussion three boxes very hard for you to do reading the best thing is every two cm you draw one i think we can all say the axis is zero has anyone gotten that x's mark so far maybe maybe later i checked lah all right so accidental why because you should label so how would you label this well my friends um one two three four four boxes is one this is a bit dicey but sure 0.25 0.50 0.75 1.00 okay this one is zero don't appreciate if there's a zero here all right so cannot and furthermore the graph is too small one two three only three big boxes only nine enough i need at least four big boxes half of the graph grid okay so labeling itself is fine but labeling of the axis is not good all right so let's look at the plot i think the plot points um are okay provided the candidate got plot them correctly now i don't know you can give good faith quality is okay can best fit [Music] line three below and one on top zero all right um gradient i don't see a wrangler triangle i don't see working if it's on another page then i'm sorry two out of five it shouldn't be right because there's only two pages you calculate in front okay i go in front of you if it's calculated in front then you just mark accordingly now okay all right so next um this one is okay interesting okay fine fine size is one two three four five one two three four five six seven okay size is nice and big so axis is one mark yay plot one i'm again assuming the candidate plot correctly because 47 minute now guys okay anyway um the quality is a bit dicey because the points are a bit far so it goes here to here actually sometimes we check vertically one so you can see vertically it's more than one cm like this one actually vertically is also more than one cm every max game is different sometimes we check horizontally sometimes we check vertically you wouldn't know okay you would not know but this one is quite far more than definitely more than one already so yeah so this one zero breastfeed line let's say let us say [Music] actually this is okay best fit line because you have two below and two on top and they balance out so it's okay gradient i see the triangle is the working here is the working on the other page okay let me try to identify the candidate is it this one is it that one is it in order actually i don't know like people give me one this one so if it's this one no wait what is happening i also don't know i think we find the candidate oh this is the melee ohm candidate actually yeah this one uh you take millivolt divided by milli ampere the melee outma so why here still got mini one way some more why this one shouldn't have melee anymore okay all right i'm assuming the same people are watching the same videos now okay so this one okay uh this one i'm just blindly guessing at this point in time because i don't think i was given these scripts in order this one i don't know this one okay i wouldn't know so i'm going to assume that it's the this one looks like this one yeah the the signage is the same i don't see any working for gradient though my friend this is the working for gradient why is this the working for gradient why is it working for gradient here why is resistivity the working of gradient i'm very confused so zero see true story of what happens inside an examiner's mind they don't understand you're working they try to find it and they still don't understand then kayla zero find the gradient separately that only include in your analysis do not skip step in paper three all the steps are important three out five okay that's all the time yeah for today i'm sorry to take up so long okay i will see you in part three where we will talk about what are we going to do with the gradient value that you have found and yeah so don't forget it's very important and it's very easy to lose marks on nice so i think the average score here is about 2.5 out of 5. much room for improvement all right again why intercept remember i will see you in the next video where we will talk about how to analyze y-intercept and gradient and write your final answer see you then