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
EXPERIMENT – PART I
— Coffee maker
— 3 identical mugs
— 3 meat- or candy- thermometers
— 3 stopwatches
1. Make a pot of coffee
2. Pour exactly 1 cup of hot coffee 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.
EXPERIMENT – PART II
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!