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How to graph data for your science fair project

Posted by on April 8, 2012

Once you have your data, you will need to present it to your teacher and science fair judges. In a science publication, you would choose between a table and a graph, but for the science fair project it is acceptable, and even encouraged, to showcase the data in both forms. If you have to pick (teacher’s rules), then a graph (picture) is better than a table (numbers), EXCEPT that most scientists really, really like numbers – so we are happy to see the table too.

Type of graphs: Your first choice is to determine which type of graph would best communicate your findings. Your basic choices are bar graph, line graph, pie chart, or scatter plot.

BAR GRAPH – This is the most common type for science fair projects. You may select a bar graph when your independent variable is qualitative (categories) or quantitative (numbers). It is generally better to group the data by TREATMENT instead of TRIAL # because it allows a better comparison of variation within the treatment. This might not be intuitive if you collected by trial, but it is the better way to showcase your results.

An example of a bar graph

Look closely and make sure your bar graph has all the highlighted parts:

Independent variable may be qualitative or quantitative

LINE GRAPH – This is the second most common, but frequently used incorrectly, so be careful here. You should only select a line graph if your independent variable is quantitative (numbers) and you hypothesized that the changes in the independent variable would result in changes in the dependent one. For example, line graphs are great for showing changes in the dependent variable over time or distance along a transect.

An example of a line graph

Again double check the axes:

Independent variable MUST be quantitative

PIE CHART – Pie charts are good for projects that have qualitative independent variables and have generated data that can be expressed as percentages of the total. For example, if your data were counts (i.e. the number of times something happened), then this might be your best choice to compare different treatments.

An example of a pie chart

SCATTER PLOT – If the purpose is to see if the variables are related (common in environmental projects), but there was not a clear choice for independent and dependent variables (for example wind speed and water temperature), then a scatter plot would be your best choice. This option typically requires much more data than the others to observe a trend.

Scatter plots are also called X-Y plots

Scientists do not label graphs with a title, but if your teacher asks for one — make sure that is there too.

25 Responses to How to graph data for your science fair project

  1. jeffery

    this is a nice thing you are doing

  2. Sharee

    Excellent information, great page theme, continue the great work

  3. carolina

    i really need help on my data

    • Dr. Maille Lyons

      What do you need, that you didn’t find here?

      First, think about which variable did you change? – that will be your INDEPENDENT variable and it will go on the x-axis (horizontal one). Now determine your DEPENDENT variable – it is the thing that you actually measured or counted. These data will go on the y-axis (vertical one).

      If your independent variable is quantitative (numbers) then you could do a LINE graph or a BAR graph, but if your independent variable is qualitative (categories like colors, or male vs. female, or high-med-low) then you should be making a bar graph.

      Hope that helps, if not – ask a more specific question – what help do you need?

  4. isabella

    I am confused. I am in 6th grade and I did my project on my question can I grow stalactites in a manipulated environment. I did two experiments. One in the house with a set temp of 76 degrees, and the other in the garage at random temps. How would I do a graph? They both grew but differently. I am not sure what kind of graph to do, thank you

    • Dr. Maille Lyons

      OK – let’s take a look at what you did:

      1 experiment with 2 conditions: a. constant temperature condition and b. variable temperature condition

      How did you measure growth?
      If you only measured growth one time at the end, then you could do a bar graph showing the total growth attained. One bar for each condition – bigger bar wins!

      If you measured growth several times over the course of the time you let them grow, then you could do a line graph showing growth (y-axis) over time (x-axis). One line for each condition.

      You may want to re-phrase your question: What is the effect of temperature variation on stalactite growth?

      Hope that helps!

  5. Sydney

    I don’t know how to graph my data. I did which product affects the decaying of apple slices the most. I used Epsom salt, salt, and baking soda. The salt slowed down the decaying the most, and the baking soda sped it up the most. How do I put this into a graph????

    • Dr. Maille Lyons

      OK – what did you actually measure? In other words, how did you get to the conclusion that the salt slowed down the decaying the most?

      Was it time (how long it took each one to decay?)
      Was it weight loss? or Percent weight loss?
      Was it percent color change?

      You will most likely be doing a BAR GRAPH- with each treatment: Epsom salt, salt, and baking soda on the x-axis and whatever you measured on the y-axis

      If you did a control (no treatment) – you can calculate the percent change from the control value

  6. Becky McKenzie

    I did an experiment melting M&M’s, trying to see if certain colors melt faster than others. I am trying to find a graph to show my results. I have not made a graph on the computer before. Please advise me as to website that would be best. Thanks.

  7. Martha

    I am doing the experiment how sodas affect tooth decay. Choose 4 sodas placed teeth in each measuring 600ml watching changes to each tooth over a 5 day period to observe which soda caused the quickest decay. How do i place the information on a graph?
    Thank you.

    • Dr. Maille Lyons

      How are you measuring “decay” – visually or will you weigh them… or ?

      If you have a quantitative dependent (time, weight, size, etc.) then that will go on your y-axis with type of soda on your x-axis.

  8. Sydney Juranty

    Thanks so much!

  9. Christopher Gallagher

    I am doing my science fair project on Wind using a homemade anemometer. I will be testing the wind every morning for 7 days and then compare the wind activity for the same seven days last year. How do set up a graph in excel? I am so confused and dont know how to set the formulas up-please help!

    • Dr. Maille Lyons

      First, what was your question?

      Based on what you have provided, it sounds like you want to compare this year’s 7 days to last year’s 7 days. I would recommend a line graph with day (1-7) on the x-axis and wind speed on the y-axis. Put one set of data (e.g. this year) in one color and the other set (e.g. last year) in another color. You will be able to see which line was “higher” (i.e. more windy) and which line was “more variable” and hopefully that will answer whatever question you selected.

      You can use excel to make a graph, but it will be hard for me to explain how if you aren’t familiar with excel. I generally recommend this website:

      (cut and paste into your browser; or Google “Create a Graph”)

  10. sheila scott

    Hello, I am doing my 6th grade Science Fair Project on Whether Pop Cans will sink or float. I used Coke, Diet Coke, Coke Zero, Caffeine Free Diet Coke, and Caffeine Free Coke Zero. They all floated except for the Coke. How would I do a Graph or Chart for this.

    Thank you for you help
    Sheila Scott

    • Dr. Maille Lyons

      How many cans per type of soda did you do? Were the results all the same? You should probably just do a table with Type of Soda across the top and sink and float down the side: then fill it in with yes or no.

  11. Darlene Couch

    My daughter is doing a science fair project on which soda stains teeth the most. She is using visual comparisons. How can she graph and chart this

    • Dr. Maille Lyons

      Generally, you can’t graph qualitative variables like which one stains the most unless you can come up with some sort of a rating scale. For example if she sets up a sequence from “no staining = 0″ to “light staining = 1″ to “moderate staining = 2″ etc. up to heavy staining with whatever number you are on… then she could make a bar graph with soda on the x-axis and staining on the y-axis. You may need to establish the rating scale using something like time (so “light staining = 1″ would be the equivalent to soaking for 1 (hour or day or week depending on the scale you are making)). You might need a rating scale for each soda, for example, you shouldn’t use a staining scale made with a cola to evaluate an orange soda.

      Alternatively she might be able to re-phrase the question looking at how long (time is a quantitative variable) does it take to get to a certain level of staining and then compare “time” as a proxy for “stains the most”.

  12. Luly Fundies

    Please help me, i think i should use a bar graph and have different colors for each trial, because i am finding the speed of waves through three trial. (by waves i mean waves from the eleectromagnetic spectrum)

    • Dr. Maille Lyons

      I need a bit more information… Sounds like you could use a bar graph for that type of data. You would have speed on the y-axis and what ever was different in each trial on the x-axis

  13. Jessie

    My daughter is in 3rd grade and has to show a graph or table but I have no idea how to help her with this… Her project was sucking an egg through a bottle and all three times the egg went in… How would you graph it or make a table with that information?????

    • Dr. Maille Lyons

      If she measured the time it took for the egg to go in, she could do a bar graph of treatment (x-axis; i.e. different conditions under which she tested the egg drop) vs. time (y-axis). If she didn’t measure the time but noted which conditions made the egg go in faster, she could make a table and rank them slow, medium, fast.

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