How to Draw a Scientific Graph: A Step-by-Step Guide

Updated on June 10, 2016

A very poor, but not unique, example of a graph

This graph is (intentionally) riddled with problems that are commonly seen in student's work. Find out how to avoid these costly mistakes below.
This graph is (intentionally) riddled with problems that are commonly seen in student's work. Find out how to avoid these costly mistakes below. | Source

Graphs - learn to love them!

I hear this moan more than any other - it also is one of the most exasperating:

"Why do we have to draw graphs in Science - it's not maths!"

With Ofsted going on about 'integrated curricula' it is important that students do not see subjects as insular and cut off from each other. The skills learnt in Math, English and Technology are readily and necessarily transferable to the Scientific arena.

Graphs are one of the most important tools available to scientists (young and old) to display data. They are:

  1. Easy to interpret
  2. Display a large amount of information in a small (ish) space
  3. Easy to draw!
  4. Worth LOADS of marks in coursework and in exams (typically 4-8marks)

It is a source of endless annoyance seeing a pupil miss a grade boundary by a couple of marks only to scrutinise the paper and see 3 marks thrown away due to poor graphing. This article will take you through the golden rules of drawing graphs, applicable to all exam boards, all situations, all the time. They are even up on my classroom wall as my 'Tips for the Top'

Common Mistakes, and how to avoid them

At least half the marks for any graph question are awarded for presenting your graph according to standard conventions; this is before the actual content has even been assessed. Before moving on from any graph question or from a graph section of your coursework, ensure you have followed the 6 Graph Commandments

  1. Thou shalt draw your graph in pencil with a ruler.
  2. Thou shalt use all thy graph paper.
  3. Thou shalt label your axes.
  4. Thou shalt always give units.
  5. Thou shalt not draw bar graphs.
  6. Thou shalt not play dot-to-dot with thy data points!

Taking a closer look at that graph - this person has broken five of the six commandments. Even if all their data points are correctly plotted, they have already thrown away half the marks!
Taking a closer look at that graph - this person has broken five of the six commandments. Even if all their data points are correctly plotted, they have already thrown away half the marks!

Be Specific

If you have ticked off each of the Commandments, you are halfway to achieving a good overall mark for this particular graph. But now it is time to pick up question specific marks...

  1. Give your graph a descriptive title. E.g.: A Graph to show the effect of x on y
  2. Ensure you have put your graph the right way around. Your x axis should always show the independent variable - this is the variable you are changing. Your y axis should always plot the dependent variable - this is the variable you are measuring. For example, when looking at the effect of temperature on rate of reaction (a classic chemistry investigation), you change the temperature and measure the rate. As such, temperature goes on your x axis (it is independent) and rate goes on your y axis (it is dependent)
  3. Ensure you plot your data carefully, along the corridor and up the stairs. Mark your data point with a small x. If you are plotting multiple data sets on one graph (a prerequisite for the highest marks in some syllabi) then use a small o or l or similar to distiguish between data sets.
  4. If plotting multiple data sets, WRITE OUT A KEY/LEGEND!
  5. Do not play dot-to-dot. I know I have stated this before, but I so often see jagged connected lines on graphs from my students. Only very rarely are data points connected in this way. More often, we are seeking the trend or pattern that our results show, for that we need...
  6. DRAW A LINE OF BEST FIT. These lines pass through or near as many data points as possible. They can either be straight lined, or a smooth curve. Look for the pattern to decide which is most appropriate.
  7. TIP FOR THE TOP: circle your anomalous results (any outliers that do not fit your trend) and label them in your key/legend. This will net you extra points for seconds extra work.

A near-perfect graph! Following all of the commandments and many of the higher tier specs too. Beautiful.
A near-perfect graph! Following all of the commandments and many of the higher tier specs too. Beautiful. | Source

Don't forget to ask

Depending on the coursework you are completing, the criteria for accessing the very top marks differ. For rates of reaction, you are required to find the gradient of your graph; For osmosis and other biological investigations you are required to add error bars; still other investigations require statistical interventions such as Chi-Squared tests. Graphs are such easy places to pick up precious points that it would be foolish to not ask your teacher/lecturer/professor etc what the marking criteria are for the highest echelons. Don't waste marks by not asking - by following all the above advice, you have already attained 6/8 marks: now shoot for the last two!

Happy Graphing!

Questions & Answers

    Comments

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      • profile image

        Ell 

        7 weeks ago

        Thanks for this article! So helpful

      • profile image

        Anon 

        2 months ago

        Please show me how to convert a table into a graph

      • profile image

        Nafisat ndidi lawal 

        3 months ago

        Thank you because i have now realised my mistakes.thank a lot

      • profile image

        Jaedon Fitisemanu 

        4 months ago

        Thanx Mate

      • profile image

        happy tea pot who has a exam in less then 24 hrs 

        5 months ago

        thank q

      • profile image

        dhanush sl 

        8 months ago

        show the video

      • profile image

        Leeds boi xox gossip girl XD XD 

        8 months ago

        Thanks for help. Got marks off for not drawing graphs right last time. Great help my middle aged friend

      • profile image

        Owen bridges yr7 student 

        9 months ago

        this has really helped me with my homework and i can assure you i will come back to owlcation and learn more ready to do my homework

      • profile image

        King Poop Emoji 

        10 months ago

        I do all my writing in pen. The ink shows up better, and in my opinion, pens are superior to pencils.

      • profile image

        hannah 

        10 months ago

        thank you!!!

        this is going to help me with graphing in the future

      • profile image

        ngi ayuk 

        17 months ago

        Thanks

      • profile image

        LeisaK 

        17 months ago

        Thanks for the examples. I would suggest putting zero in the bottom left corner.

      • profile image

        Emma 

        17 months ago

        Thank you so much. I have lost so many marks for my graphs and this has explained them in a way I understand! Thank you so much !

      • profile image

        D Hardy 

        21 months ago

        According to AQA Biology all points should be joined by straight lines

      • profile image

        Marcus 

        21 months ago

        Thanks so much have an exam tommorow and had failed previously on graphing so thanks for this should hopefully help me improve

      • profile image

        Luize 

        2 years ago

        Commandment number 2 should be: Thou shalt give your graph a heading!

        Well done. I'm busy with an extensive handout for my kids and was looking for examples of line graphs when I stumbled upon your page. This is well summarized - good job!

      • profile image

        helpmewithschool 

        3 years ago

        ive been freaking out over a test tomorrow and couldnt find some of these answers anywhere so thank you so much im incredibly grateful. you made me so happy i decided to get an account here just so i could comment on this and thank you. please keep making really great hubs

      • profile image

        christian eneojo 

        3 years ago

        impressive information...

      • profile image

        tine 

        3 years ago

        Yeah but how you draw it?

      • profile image

        TM 

        5 years ago

        all teachers keep explaining this to me but i never get it,i just got it now!thanks!

      • TFScientist profile imageAUTHOR

        Rhys Baker 

        6 years ago from Peterborough, UK

        "I'm also not sure why there's no title to your graphs"

        For my first and third graphs there are titles :S The second graph deliberately doesn't have one. Thanks for the comment. You would be surprised how often degree level students forget the basics!

      • freemarketingnow profile image

        freemarketingnow 

        6 years ago from California

        I'm not sure why I can't draw bar graphs. I'm also not sure why there's no title to your graphs. Otherwise, this looks good for someone in elementary school or junior high. Good work for a first hub!

      • Teresa Coppens profile image

        Teresa Coppens 

        6 years ago from Ontario, Canada

        I was just teaching the importance of proper graph construction to a grade 4 class, they were working primarily with bar graphs however but the principle remains the same. Fantastic resource.

      • TFScientist profile imageAUTHOR

        Rhys Baker 

        6 years ago from Peterborough, UK

        Thanks for your kind words :)

      • bloggernotjogger profile image

        bloggernotjogger 

        6 years ago from La Cala de Mijas, Spain

        Nice hub,

        I voted up because the hub explained everything the title said it would. The links at the top are great too. I have more material to read.

      • TFScientist profile imageAUTHOR

        Rhys Baker 

        6 years ago from Peterborough, UK

        @Ms Dee - huge thanks for your specific comments - really helpful. I will try to keep this as a standard for my hubs

        @rjsadowski: Couldn't agree more

      • TFScientist profile imageAUTHOR

        Rhys Baker 

        6 years ago from Peterborough, UK

        Many of my pupils come to secondary school with a good idea of how to draw bar graphs...and nothing else. As such, they plot bar graphs at all times (talk about annoying!) Hence my 5th commandment. Bar graphs are only suitable when graphing the results of a tally chart (categories vs frequency) and are used extremely infrequently about Yr7 in Science.

        @FitnezzJim - I agree RE graphing on PCs (although Excel and Minitab are still very poor at drawing lines of best fit) has now become a norm - for good or ill. However, until all exams and coursework are submitted by PC, the more 'primitive' methods are still relevent...and you would be gobsmacked how many pupils submit graphs drawn on lined or plain paper, in pen, without a ruler. GRRR! :)

        Thank you for the kind words so far. I'm glad I am making myself useful.

      • FitnezzJim profile image

        FitnezzJim 

        6 years ago from Fredericksburg, Virginia

        My goodness, I use graphs all the time to quickly and intuitively convey messages. Unfortunately, I suppose I no longer follow the rules, although I was taught all those rules when I was growing up.

        Nowadays, a good graph can be done in Excel (so out goes the paper and pencil rules). I try to label the plots and axes, but truth to say, I almost always get comments to make them more readable (bad habit ... when you know what you plotted, and are expecting to tell the story when you are sharing the graph, then the verbal part is usually when the axes get labelled for the viewer. It's part of a technique to engage the audience while presenting). So the units and labelling rules are often broken. Bar graphs have their place, but not for the plots I make. The connect the dots rule usually does not get broken since the data is about as random as the stock market, with both the independent and dependent variables showing randomness. Those sort of graphs look like scribbles if you connect the dots.

        Great Hub, and excellent point that graphs are just another of the many tools a good mathematics person can draw on to help convey messages obscured in data.

        Welcome to Hub Pages.

      • rjsadowski profile image

        rjsadowski 

        6 years ago

        A very useful hub. People don't graph data enough, probably because they don't know how. Remember the words of that great philosopher, Hugh Heffner, "One picture is worth a thousand words".

      • Ms Dee profile image

        Deidre Shelden 

        6 years ago from Texas, USA

        What a GREAT first hub! I'm impressed. I've not seen an article about this before. What is the reason behind the 5th commandment? I'm curious. A good title is so very important and you seem to have a good one here :). If it were me, I would not put any more links in than you already have. You have not gone overboard on the tags, either. So, great job!

      • TFScientist profile imageAUTHOR

        Rhys Baker 

        6 years ago from Peterborough, UK

        This is my first hub so please comment! Any improvements, suggestions or criticisms are gratefully received.

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