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One Day Unique Science Fair Experiment with COFFEE!

Posted by on August 12, 2012

I usually do not write out all the details of an experiment because I want you (whether you are a mentor or a student) to have a hand in designing the experiment. I think that just following directions of a detailed procedure that someone else wrote, isn’t really experiencing science. It’s closer to baking or cooking.

However, here I will give you a basic design and then you can twist this into a unique science fair project by targeting a different variable. But, if you are in a crunch – and the project is due TOMORROW then just do Part I of the experiment explained below. It should get you a decent grade because it is technically correct.


First ask yourself: How long does it take for coffee to reach a safe temperature to drink?

Your gut reaction might be: “it depends” – and you would be correct, it does depend on many factors, some of which you can use in Part II to modify this basic design into your own unique project, but for now just estimate the time. Note that there is NO WRONG ANSWER here – it is just whatever you think it might be (10 seconds? 10 minutes? 10 hours?).

Now think about what information you need to know in order to determine a quantitative, objective answer. For example, you would probably need to know:

What is a safe temperature to drink?

— To find the answer, you could do some research or you could use:
— 143 degrees F (62 degrees C)

What is the temperature of coffee right after it is brewed?

— To find the answer, you will measure it yourself

How long does it take for a liquid to go from one temperature to another?

— To find the answer, you will conduct an experiment




— Coffee maker
— Coffee
— 3 identical mugs
— 3 meat- or candy- thermometers
— 3 stopwatches



1. Make a pot of coffee
2. Pour exactly 1 cup of water into 1 mug, start the stop watch, then measure and record the temperature with the thermometer.
3. Repeat with the second mug and then the third mug.
4. Measure the temperature every minute until the temperature is lower than the safe temperature you found in your research or the one I have listed above. You might want to continue to measure the temperature for a few more minutes to have a nicer looking graph.
5. Record the total time for each mug-thermometer-stopwatch set up
6. Graph time vs. temperature and add a horizontal line for the safe temperature

What is your independent variable?

— Answer: time – which means time goes on the x-axis

What is your dependent variable?
— Answer: temperature – so put temperature on the y-axis

How close were you to your hypothesis? (Hint: your hypothesis was the time you estimated BEFORE you started.



Here is where the creativity comes in. You will now compare the results above to the results from a second run with ONE and only one variable (i.e. factor) changed.

So what factors might the answer also depend on:

• Volume of coffee?
• Strength of the brew?
• Type of coffee maker?
• Type of container (i.e. material the mug/cup is made of)?
• Amount of cream added?
• Adding Cream vs. Milk (whole, 1%, 2%)?
• Amount of sugar added?
• Adding Sugar vs. Sweetener?
• Type of coffee?
• Coffee vs. Tea vs. Hot chocolate?
• Store bought vs. Home brewed?
• Different coffee shops or different major brands?
• Dunkin Donuts ® vs. Starbucks ®

Can you think of any others?


Now, the first set of results are your control.

The second set of results are your experimental results to answer a new question:

How does ____________ affect the time to reach a safe temperature for drinking coffee?

Hypothesis: If ____________ then the time to reach a safe temperature will
(pick one) increase/decrease/stay the same

Experiment: Repeat the same experiment, but make your change. Also make sure you cool the coffee maker and the mugs back to room temperature.

Note that the more time (and interest) that you have, the more times you could repeat the experiment with other variables. Generally, the more you do, the more competitive the project will be.

Good luck and have fun!

24 Responses to One Day Unique Science Fair Experiment with COFFEE!

  1. aishwarya

    thanks.. i not only got the exp but also the conclusion

  2. Alani

    Thank you so much! I was looking for a good science fair question and it really sounded fun! I didn’t copy the procedure of materials or any of that stuff it just helped me make an outline of what i should do! Thanks a million! :)

  3. rebekah

    i luv this thank u soo much lol

  4. Lori

    Is there anyway to alter this experiment to use tea?

  5. Kayla

    What’s the conclusion ?

    • Dr. Maille Lyons

      Generally, the conclusion is whether your results support (i.e. agree with) or do not support (i.e. do not agree with) your hypothesis (this is why the hypothesis is made BEFORE you conduct an experiment).

      In this case, you also have a practical conclusion of the amount of time you need to wait for the coffee to be a safe temperature to drink without the risk of burning your tongue!

  6. Ellen

    This was fantastic! We (my son and I) set ours up a little differently. We have a Keurig so each cup was brewed independently. We had 3 different cups, all were the same size but one was tall and the other 2 wide. Of the wide, one was black and the other white. We tested each to see how long it would take to cool off as a whole and which one would cool off the fastest. We were wrong, The tall thin cup stayed the hottest longest and the black one cooled the fastest. We thought the black would cool the slowest because black as a color hold the heat in. We were wrong. He also guessed about 20 mins to cool completely. We were Way off on that estimate too. Anyway, this was my 1st science fair project since I was a child and it was a lot of fun!!! Thank you so much!!! Ellen :)

  7. Dr. Maille Lyons

    Your best bet is to do this experiment with as many variables as you have time to do in a Quest for the Perfect Cup (you can use that as your title!).

    Part 1: Figure out how long until black coffee reaches a safe temperature.
    Part 2: Figure out how the amount of cream affects time to reach a safe temperature.
    Part 3: Figure out if there is a difference between cream, whole milk, 2%, and skim milk.
    Part 4: Figure out how the size of the cup affects time to reach a safe temperature.
    Part 5: Figure out how the type of cup affects the time to reach a safe temperature.
    Part 6: Figure out if there is a difference between home brewed and at least 2 coffee stores.

    Put it all together – what combination will get you a safe cup to drink in the shortest amount of time and what combination will make you wait the longest.

    It’s a practical application of a science experiment and , fortunately for you, it will look like more work than it actually was…

    Good Luck and next year start earlier!

  8. kat

    you saved me! my project was do the day after i saw this really i was worried thx alot i got a good grade!

  9. Julia

    Thaaaaaaaankyouu so much , seriously if it wasn’t for you i’d probably have no science project at all one question though I cant really understand the variable part ?? can you explain thank you tons Dr.


    • Dr. Maille Lyons

      Variables are any component that you could change. Independent variables are ones you care about, dependent variables are ones you will measure, and constant variables (is an oxymoron) are ones you keep the same because you don’t care about them (as much).

  10. Julia

    and can it also work with just two cups ????
    thank you

    ~juuuuuliaaaaa (:

    • Dr. Maille Lyons

      No – you need to do three, because if you only do 2 and the results are different – then you won’t know which one is more accurate.

  11. Hanna

    What would the purpose be? In my project I have to have a purpose. If I don’t have one, my teacher will reject the idea. I really like this one. Plz reply. Thanks!

  12. Jazzy Montez Casias

    I can’t thank you enough right now!!! :)

  13. Wesley

    What would the constants be? The coffee mugs?? Thanks so much for your great ideas! You saved my son!!! And my sanity!!!!

    • Dr. Maille Lyons

      The constants are everything that remained the same between trials. These are the “things” that you don’t really care about, you don’t really want to know how they affect the outcome, so you don’t changes them (i.e. they stay constant).

      Yes, the mugs – but also the amount of coffee, the type of coffee (depending on the actually question you asked), etc.

      • Wesley

        Thank you!!! Another question. How should i word the title ? Teacher wants it to begin with “what affects…. OR What is the affect of……?
        I’m a mom doing this for my a honor roll child. Time got away and life happened. My child knows this WILL NEVER HAPPEN AGAIN!!!
        I’m doing it a bit different. Im going to test temp of coffee straight & coffe with creamer. And how long it takes for it to be safe to drink without being burnt. Any help would be so appreciated!!!
        Sincerely- concerned momma

        • Dr. Maille Lyons

          No worries… lots of moms have been there!!

          OK – it looks like the question could be stated as:

          –What is the effect of creamer on the time it takes to reach a safe temperature to drink coffee? OR

          –Does creamer affect the time it takes to reach a safe temperature for drinking coffee? OR

          –How much does the presence of creamer affect the time it takes to reach a safe temperature for drinking coffee?

          Then your independent variable (the thing you change) is the creamer (so the coffee without the creamer is the “control”; although you are also monitoring time) and your dependent variable (the thing you measure) is temperature (which you will then use to calculate the amount of time).

          Best design: 2 mugs of coffee – each with its own thermometer and poured from same pot. Take starting temperatures of each (time zero), add 1 tablespoon of creamer to one mug. Measure temperature every minute until below safe temperature. Calculate difference. Compare times. REPEAT 3 times.

          Data: Make a bar graph with “coffee” and “coffee with creamer” on x-axis and time to safe temperature on y-axis. You could also make a line graph with time on the x-axis and temperature on the y-axis with two different colored lines (one for coffee and one for coffee plus creamer).

          Constants: coffee (pour the same amount in each cup, for example 1 cup of coffee in each mug); the mugs; the kitchen conditions (e.g. temperature of your kitchen).

          Conclusion: The presence of creamer reduces the time it takes to reach a safe drinking temperature by ____ minutes. This is important to any coffee drinker who uses cream because we are tired of burning our lips/tongue.


          Now, if you want to get crazy, you can repeat with skim milk (so you can compare: control, creamer and skim milk) OR you can repeat with different amounts of creamer (1/2 T, vs. 1T, vs. 1 1/2T vs. 2) to see if you get a “dose-response” i.e. does more creamer make it proportionally safer, faster OR you can just stop…

          GOOD LUCK

          • Wesley

            Wow. You are pretty amazing!! I’d never think in a million years anybody would reply so very quickly along with the true thoughtfulness of it all. You have to be a wonderful person. I will most definitely be spreading the word about this (your?) website. I have another younger child who will have to do science projectS in the near future and we will be utilizing THIS site again. Thank you again so very much. Be blessed. Do you have an email??

          • Dr. Maille Lyons

            Thank you. I just want kids to love science and unfortunately the science fair experience turns many of them off. My email is on the “Meet the Coach” tab:

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