BCBT 100 Rasmussen College Unit 1 Working With Data Lab Report

Goals of the experiment:

• Develop hypotheses
• Dissect the components of good experiment design
• Interpret data by organizing, graphing, and finding averages and patterns

Unit 1 Lab: BCBT 100
Working with data
Goals of the experiment:
• Develop hypotheses
• Dissect the components of good experiment design
• Interpret data by organizing, graphing, and finding averages and patterns
In this ‘dry’ lab we will practice the process of the scientific method, from developing a hypothesis to analyzing data. As
it is the beginning of the semester, you may not yet have your lab materials for this class so all of the actual lab
experiments and data collection have been done for you. Go through the two experiments described in this lab activity
and answer the questions asked. Then save and re-upload this completed document to the assignment folder. For
documentation of this lab, go ahead and take a selfie of yourself working on this lab and insert it into the document
here:
[Insert picture documentation of you working on this lab here]
Remember that if you do not document your labs appropriately, you will receive no credit for the lab.
Part 1: When things don’t freeze: Freezing point depression
Matter exists in phases, solid, liquid, and gas. We manipulate this often in the kitchen by freezing and boiling our foods.
We know that pure water behaves very predictably, freezing at 32F. However, we are often able to manipulate that
freezing point. When we mix things with water we can often produce substances that aren’t designed to fully freeze.
The first lab activity for this module looks at what happens when we add substances to water that change how it
freezes.
One thing that scientists have discovered is that when you add substances to water, you can increase the boiling point or
decrease the freezing point. This is known as boiling point elevation or freezing point depression. We know that water
changes phases from a liquid to a solid at 32°F, but we also know that if you put salt on a road the ice will not freeze
unless the temperature is quite a bit lower than 32°F. We also see this in our kitchens. A bottle of alcohol doesn’t freeze
in your kitchen freezer. A sugary drink may not fully freeze either.
It’s a hot summer day and you want to throw a party. You hear about an awesome idea to make ice out of your choice of
beverage so you don’t water it down. You’re making some delicious lemonade, and you want some nice, non-watered
down lemonade ice-cubes to go with it. You need to figure out how concentrated you can make your lemonade and still
get ice cubes (instead of slush) when you freeze it. You need a lot of ice, so you’d like to use your deep freezer, regular
freezer, and even the little freezer in your old mini-fridge.
You decide to put on your #kitchenchemist hat and do an experiment to see just how concentrated you can make your
drink and still end up with ice cubes. In science, you start any experiment by asking a question about a situation that you
can use the scientific method to solve. In this case, your scientific question is “How concentrated can my lemonade be
and still freeze in my freezer?”
1. Developing Hypotheses
A hypothesis is the basis for the set-up of your experiment. It is a rational guess at the answer to your scientific question.
Most importantly, it needs to be something you can test. You will want to identify one thing you want to change, and
then predict how making that change will affect your results.
Your initial lemonade recipe is very simple:
• 1 cup sugar
• 6 cups water
• 1 teaspoon lemonade flavoring
Stir together and serve with ice
1A. (1pt) Which of the three items in the recipe is MOST likely to be responsible if your lemonade ice cubes don’t
freeze solid? Justify/explain your choice.
[Insert answer here]
1B. (1pt) Do you think increasing the amount of the ingredient you chose for part A will cause your lemonade to
freeze at a temperature higher or lower than 32°F? Explain why you think so.
[Insert answer here]
If you put your answer to part B in the format of:
I think that if I increase the amount of [item in the recipe], my ice cubes will freeze at a [higher/lower]
temperature than the temperature of my freezer because [explanation of choice]
Then you will have written a hypothesis for the experiment. The best part: if you chose one of the ingredients in the
recipe (a testable variable) and your explanation is reasonable (or based on logic as opposed to say, magic), then you
just received a perfect score for your hypothesis! That’s right, your hypothesis DOES NOT need to be correct. It is a best
guess and the basis for setting up your experiment. Under no circumstances should you wait until you get to the end of
your experiment and then go back and change your hypothesis to make it ‘correct’! That isn’t how science works, and is
actually a very dangerous practice, as no hypothesis is ever ‘correct’ or ‘incorrect’. Some hypothesis are supported by a
particular experiment, some aren’t supported. However, it may turn out to be more complicated when new experiments
are carried out. Science is about exploring relationships and ideas to try to understand them better, not being ‘right’ or
‘wrong’. Science’s relationship status will always be ‘it’s complicated’.
There are many things you could test, but for the sake of this assignment your professor decided to design an
experiment to see if the concentration of sugar will change how the recipe freezes.
Fill out your hypothesis for this sugar changing experiment:
1C. (1pt) I think that if I increase the amount of sugar, my ice cubes will become [more/less] frozen at the
temperature of the freezer because [explanation of choice]
2. Designing the experiment and collecting data
Designing the experiment involves changing the variable we identified and measuring the outcome we are interested in.
The variable we identified to change is the amount of sugar in our recipe. For this experiment, we will freeze five
different concentrations of sugar in the recipe:
•
•
•
•
•
Lower sugar ratio: 1 part sugar to 12 parts water (8% sugar concentration)
Current sugar ratio: 1 part sugar to 6 parts water (14% sugar concentration)
Higher sugar ratio: 1 part sugar to 3 parts water (25% sugar concentration)
Very high sugar ratio: 1 parts sugar to 1 part water (50% sugar concentration)
Extremely high sugar ratio: 1 part sugar to ½ part water (67% sugar concentration)
We then need to measure the outcome, or how frozen it becomes in the freezer.
There are several possible measurements we could make:
1. Time for lemonade to freeze.
2. Temperature of the lemonade in the freezer.
3. The rate at which the lemonade freezes (how fast the recipe freezes).
4. Assessment of the ice (hard cube vs slushy).
You will want to think about each of the possible measurements and consider both how they would be measured and
also reflect on things you might have to take into consideration with each of them. Fill out the empty boxes in table
below. Several boxes have been completed for you.
2A. (3pts) Complete the table below:
How would we
measure it?
Time
A clock or timer
What does it tell
us?
Concerns or
considerations?
1.
2.
How do we
decide when our
recipe is frozen?
Freezers are all
at different
temperatures
and efficiencies.
One freezer may
be very different
Temperature
Rate
Measure the time it
takes to freeze and
the temperature at
which the recipe
freezes. Calculate the
time divided by
temperature change.
How cold the recipe is.
Can also tell us the
temperature at which the
recipe will freeze
The speed at which
the recipe freezes.
Slushy-ness
1.
How long will
you need to wait
to be sure the
ice is frozen?
How do you
know when it
has been in the
freezer long
enough?
3.
from another.
Our results
might not be
meaningful for
anyone else or
reproducible.
Opening the
freezer often can
cause it to not
stay cold. This
could influence
both the
temperature and
time it takes the
recipe to freeze.
2.
3.
Different
freezers are set
to different
temperatures,
how do you
account for this?
How do you
decide what
‘slushy’ looks or
feels like?
2B. (1pt) Which measurement or combination of measurements do you think would best help us to test our
hypothesis? Explain your choice.
[Insert answer here]
Like with the hypothesis, the choices you make on what to measure are a judgment call. Your choice in what to measure
is assessed based on whether or not the measurement technique gives you information that will help you figure out if
your hypothesis was supported or not. When in doubt, you can make multiple types of measurements at the same time.
You will just want to be careful to use them wisely in your analysis!
For this experiment, your instructor decided to measure the time and temperature of the five different lemonade
concentrations. They also made visual observations of when the mixture began to freeze as well as the ‘slushy-ness’ at a
variety of temperatures determined by how much resistance there was when a thermometer was poked into the
mixture.
The last part of designing our experiment involves making sure that any differences we see in our measurements are
due to our chosen variable (sugar content) rather than something else. To do this we need to 1) Ensure we are testing
only one variable and 2) Use controls and replicates
We want to be confident that as we complete our experiment, we are only measuring changes due to the sugar
content. This means we need to identify any other things that could influence our result. Things in an experiment that
can be changed over the course of the experiment are called variables. We want to make sure we never test more than
one variable at a time. One possible example is amount of liquid. If one of my lemonade ice cubes has more liquid than
another, it may influence the amount of time it takes to freeze. Another variable could be the effect of the flavoring.
Because we decided only to look at the effect of sugar concentration, it makes sense to keep the flavoring the same for
each recipe. In this case, we will choose to use just water and omit the flavoring from the recipe to keep things simple!
2C. (3pts) Brainstorm three additional things (besides sugar concentration) that if changed, could cause our time,
temperature, and/or slushy-ness measurements to change.
1. Amount of liquid in each ice cube tray well of our lemonade. A well that is twice as full may take longer to
freeze than one that is pretty empty.
2. Type and concentration of flavoring
3.
4.
5.
We also want to make sure we are getting reliable, reproducible results. For this we want to make sure our experiment
has a control and is being done using replicates. We can use pure water as a control to make sure that our samples are
freezing as expected and that nothing is wrong with our freezer. Pure water has a known freezing point of 32°F, so if we
include a 0% sugar sample it should freeze rock solid at 32°F. We also need replicates. In general, it is nice to have at
least three replicates (when feasible) of each condition you are testing. In this case, we will test three different wells of
each concentration of sugar in our lemonade.
In a normal experiment, you would now need to set up your experiment and collect data. However, since it is only the
first module and you may not have all of your lab supplies yet, this experiment has been done for you
Set up:
Five sugar solutions were prepared by mixing 1 cup of boiling water with either 4 teaspoons, 8 teaspoons, 1/3 cup, 1
cup, or 2 cups of sugar and stirred until fully dissolved. Solutions were cooled overnight in the refrigerator and two
tablespoons of each solution was put into three different wells on an ice-cube tray. All of the sugar solutions were
placed into a freezer set to -22°C (-7.5°F). Measurements were taken every ten minutes by taking the ice cube tray out
of the freezer to minimize the time the freezer door was left open.
Data:
See the Unit 1 Lab Data Excel Sheet (or PDF) in the Module 1 D2L content area for the data table for this experiment.
Image 1: Samples at 0 minutes. All wells are liquid.
Image 2: Samples at 30 minutes. Ice and slush beginning to form in 0%, 8%, 14%, and 25%
Image 3&4. Samples at 100 minutes. Note that the 50% and 67% samples did not fully freeze
3. Data Analysis
Based on the data we collected, we have many options for how we could analyze the data. Two main ones are:
1. Calculate the rate of freezing (how fast each sugar concentration freezes).
2. Determine the freezing point, or temperature at which the sugar solutions freeze.
3A. (1pt) Which of the above would allow us to determine if our solution would be frozen at a particular freezer
temperature? (Our hypothesis)
[Insert Answer Here]
Which would tell us how long we need to leave our lemonade in a particular freezer in order to freeze it? (A
related question, but not the one we are trying to answer)
[Insert Answer Here]
The freezing point of each sample is the temperature of the substance when it changes from liquid to solid. Once water
begins to freeze (or boil) all of the heat energy you take out of it (freezing) or put into it (boiling) will be put towards
making the phase transition (liquid to solid or liquid to gas) and so the temperature will generally remain the same until
the substance has either frozen or been converted entirely to steam. This becomes a bit more difficult with highly
concentrated solutions (like sugar water) because as the ice freezes, it pushes out some of the sugar, which essentially
concentrates it further and lowers its freezing point. We are looking for the ability to form ice cubes, so will use the
temperature right before the sugar solution firmly freezes as our freezing point.
Based on the data, find the average freezing point for each of the six sugar solutions. Remember that to find the average
freezing point you will add the freezing point for each of the three replicates for a given sugar solution right before it
froze solid and then divide by the number of replicates (three).
3B. (4pts) Fill out the following table with your calculation of the average freezing point for each sugar solution.
Sugar concentration
Average freezing point
0% Sugar
8% Sugar
14% Sugar
25% Sugar
50% Sugar
67% Sugar
3C. (3pts) Based on your data from table 3B, for each freezer (mini-fridge, regular fridge freezer, and deep freezer),
determine whether ice cubes could be made for each of the lemonade concentrations listed given the following
temperatures that the freezer runs at. Put a ‘yes’ in the box if the solution would form an ice cube. Put a ‘no’ in
the box if the solution would not freeze.
8% Sugar
14% Sugar
25% Sugar
Mini fridge freezer (31°F)
Regular fridge freezer (4°F)
Deep freezer (-7°F)
3D. (6pts) Insert a HAND DRAWN scatterplot graph to display the data in the table you made for question 3B. The
graph must be drawn on grid paper (a link for printable grid paper can be found in the module 1 content section
of D2L). The axes should be labeled with units, and the graph needs to include a title. Add a trend line (line of
best fit) to your graph following the instructions in the graphing slides/video posted in the module 1 content.
Remember that a trend line is a straight line that ‘summarizes’ all of your data points, not one that just connects
each of the dots on your graph!
Remember to consider carefully which data goes on which axis of your graph. The variable that you (or in this
case the instructor) chose the levels of is the independent variable and goes on the x axis. The data that was
collected as a result, or the values you (or the instructor) measured rather than chose, is the dependent variable
and goes on the y axis.
[Insert HAND DRAWN scatter plot graph with trend line here]
3E. (1pt) We use graphs to look for trends or patterns in our data that allow us to make predictions. In this case, we
want to be able to make a prediction as to whether your lemonade will be frozen at a certain temperature.
Using your trend line, predict if a 20% sugar solution would be frozen at 25°F. Explain your answer.
[Insert Answer Here]
Part 2: Rates of heating substances in the microwave
Have you ever noticed that a plate of leftovers doesn’t heat up evenly in the microwave? There are a couple variables
that are most likely to influence how your food heats up. One of the main ones is that different foods are comprised of
different types of molecules that bond to one another in differing ways (as discussed in your materials for this module).
The temperature of substance is an indication of the motion of the molecules that make up the substance, so the rate at
which different substances heat up gives us an indication of the strength of the forces that hold molecules together.
For this lab we will compare the rate, or speed at which two substances with very different types of bonds heat up. We
will use water and oil as our two substances.
4. Developing Hypotheses
We want to know how adding heat to two different substances (microwaving) will affect how quickly they heat up. For
our hypothesis, this means we need to predict what will happen when we microwave both water and oil.
From this module’s reading, you know that water and oil are very different types of molecules.
4A. (3pts) Fill out the following table describing the bonds that hold together water or oil molecules.
Water Molecules
Oil Molecules
Polar or Non-polar?
Held together by hydrogen or van der
Waals bonds?
Strength of each bond compared to a
covalent bond?
You also learned that the temperature at which a material changes phases (e.g. from liquid to gas) is determined by the
overall strength of all the bonds that hold the molecules together. The stronger the overall bonding, the more energy
necessary to break all of the bonds, and so the higher the temperature at which the material will change phases.
Based on your readings and understanding of water and oil, make a hypothesis as to whether water or oil will heat up
faster in the microwave. Remember that your hypothesis is an educated guess- as long as it is reasonable you will NEVER
be graded on whether it is ‘correct’ or not!
4B. (1pt) I think that if I add heat to water and oil using a microwave, the water will heat up at a [faster/slower] rate
than my oil because [explanation of choice]
5. Designing the experiment and collecting data
Like before, there are a number of measurements we can take related to heating up water and oil in the microwave:
1. Time for oil and water to heat up.
2. Temperature of the oil and water in the microwave.
3. The rate (speed) at which the oil and water heat up.
4. Assessment of the oil and water (is it boiling?)
For this table the measurement methods have been filled in, but you will need to add your thoughts on concerns or
considerations associated with each possible measurement.
5A. (2pts) Complete the table below by filling in the empty boxes
How would we
measure it?
What does it tell
us?
Time
A clock or timer
Temperature
Thermometer
How long heat was added
to our substance
How hot the substance is.
Can also tell us the
temperature at which the
substance will boil
Rate
Measure the time it
takes for the
temperature to
change by a certain
amount OR measure
the amount of
temperature change
that is produced by a
certain amount of
time heating
The speed at which
the substance heats
up
Assessment of phase
Visual observation of
whether gas (steam) is
present and the
substance is boiling
Helps to determine the
boiling point
Concerns or
considerations?
5B. (1pt) Which measurement or combination of measurements do you think would best help us to test our
hypothesis? Explain your choice.
[Insert answer here]
The last part of designing our experiment involves making sure that any differences we see in our measurements are
due to our chosen variable (adding heat to oil and water) rather than something else. To do this we need to 1) Ensure
we are testing only one variable and 2) Use controls and replicates
We want to be confident that as we complete our experiment, we are only measuring changes due to the sugar
content. This means we need to identify any other things that could influence our result. One possible example is the
material of my bowls. If one of my bowls holding my water/oil is plastic and the other glass, it could influence how
quickly the liquid absorbs heat.
5C. (3pts) Brainstorm three additional things that if changed, could cause our time, temperature, and/or boiling
measurements to change.
1. The material of the bowls
2.
3.
4.
We also want to make sure we are getting reliable, reproducible results. For this we want to make sure our experiment
has a control and is being done using replicates. In this case we are doing a direct comparison between two substances,
and water has a well-known boiling point, which will allow us to ensure that the heating process is working correctly.
Pure water has a known boiling point of 212°F (slight variation due to pressure/elevation). We also need replicates. In
this case, each time we heat our substance for a defined amount of time and test the temperature we have a replicate
of its rate of heating, so if we do multiple 15 second time intervals we will have many replicates.
Set up:
As before, your instructor has completed the experiment for you. Two identical microwave-safe glass containers were
filled with one cup of water or canola oil. The water container was placed in the direct center of a 900 watt microwave.
An initial temperature of the water was taken, and then the water was microwaved on high for 15 seconds, the water
quickly stirred, and the temperature recorded. This process (microwave an additional 15 seconds, stir, and record the
temperature) was repeated until the water boiled. The same process was repeated with the oil, however the procedure
was stopped once the temperature reached 300 degrees, the maximum of the thermometer.
Data:
Water Heating
Total Time in
Microwave
Temperature
(°F)
Vegetable Oil Heating
Phase
change?
Total Time in
Microwave
Temperature
(°F)
Phase Change?
(seconds)
(seconds)
0
70.3
No
0
71.0
No
15
86.1
No
15
94.2
No
30
107.9
No
30
125.9
No
45
122.3
No
45
149.0
No
60
133.9
No
60
174.2
No
75
145.5
No
75
194.9
No
90
156.2
No
90
215.2
No
105
168.2
No
105
232.1
No
120
180.6
No
120
250.8
No
135
189.2
No
135
267.2
No
150
200.4
No
150
280.2
No
165
211.9
Started
Boiling
165
290.1
No
6. Data Analysis
Based on the data we collected, we have many options for how we could analyze the data. Two main ones are:
1. Calculate the rate of heating (how fast the water and oil heated).
2. Determine the boiling point, or temperature at which the water and oil boiled.
6A. (1pt) Which of the above would allow us to determine if our solution would boil at a specific temperature? (A
related question, but not the one we are trying to answer)
[Insert Answer Here]
Which would tell us the rate at which the two substances heated up in the microwave? (Our hypothesis)
[Insert Answer Here]
Calculating the Rate of Heating
There are several ways the rate of heating could be calculated from the data that has been collected.
Option 1: You could individually take each time interval (eg. 15 seconds- 0 seconds = 15 seconds) and the amount the
temperature changed each time (86.1F-70.3F= 15.8F) and then divide the temperature by the time to find the rate for
15.8°𝐹
each time interval (15 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 = 1.05 𝑑𝑒𝑔𝑟𝑒𝑒𝑠 𝐹 𝑝𝑒𝑟 𝑠𝑒𝑐𝑜𝑛𝑑). For our first time period the water heated up at a rate of
around 1 degree per second in the microwave. You can calculate this for every 15 second time period we heated the
water in the microwave (eg. 60-75 seconds and 133.9°F-145.5°F), and then average all of the rates to get the rate of
heating for water. Repeat this process for the oil.
Option 2: You can prepare a scatter plot graph of temperature (measured, dependent variable) vs. total time in the
microwave (chosen, independent variable) for both water and oil. Include a best fit line for each substance to determine
the rate of temperature increase for each substance. Your plots can be done on a computer (if you are comfortable) or
by hand. However, if you graph by hand you must use graph paper. You can then calculate the rate of heating by finding
the slope of your best fit line. The slope of a best-fit line can be thought of as an average of the y axis per the x axis. So in
this case, the slope would be the average temperature per time of heating, or the average rate of heating! To do this,
pick two points on your best fit trendline for your water data and write down their X and Y coordinates. Use the formula
𝑌 °𝐹 𝑎𝑡 𝑠𝑒𝑐𝑜𝑛𝑑 𝑝𝑜𝑖𝑛𝑡−𝑌 °𝐹 𝑎𝑡 𝑓𝑖𝑟𝑠𝑡 𝑝𝑜𝑖𝑛𝑡
= 𝑅𝑎𝑡𝑒 (𝑑𝑒𝑔𝑟𝑒𝑒𝑠 𝐹 𝑝𝑒𝑟 𝑠𝑒𝑐𝑜𝑛𝑑). Repeat this process using the oil best fit
𝑋 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 𝑎𝑡 𝑠𝑒𝑐𝑜𝑛𝑑 𝑝𝑜𝑖𝑛𝑡−𝑋 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 𝑎𝑡 𝑓𝑖𝑟𝑠𝑡 𝑝𝑜𝑖𝑛𝑡
trendline. This method involves doing far fewer calculations than the first, but does involve making a graph.
6B. (10pts) Choose ONE of the methods above and calculate the rate of heating for both water and oil in the
microwave. You must show your work for the method you choose (either all of your calculations for the first
method or the graph, trendlines, and calculation of the slope of the best fit line for the second method.
[Insert all work for calculation of rate of heating for water and oil here]
[Insert final answer for the average rate of heating for both water and oil here. Be sure to include units!]
6C. (1pt) What was the boiling point measured for water? What can you say about the boiling point of the canola oil
based on the data collected?
[Insert answer here]
6D. (1pt) You heat up some leftover broth-based soup and a piece of bread coated in olive oil. Which substance will
get hot (reach 100F) first based on these results?
[Insert answer here]
6E. (1pt) Based on the data collected here, which substance, water or oil, must have the highest overall bond
strength? Explain how the data supports your answer.
[Insert answer here]
6F. (1pt) How does this compare to the strength of individual hydrogen/van der Waals bonds? Explain your answer
(hint: see pages 814-815 in your textbook).
[Insert answer here]
0
10
0%
Temperature (°F) Appearance
1
2
3
38.8 39.5 39.9 Liquid
35.2 35.4 35.2 Liquid
8%
Temperature (°F) Appearance
1
2
3
38.8 38.8 39.2 Liquid
33.8 35.6 34.1 Liquid
14%
Temperature (°F) Appearance
1
2
3
39.3 39.5 39.7 Liquid
31 33.6 33.6 Liquid
25%
Temperature (°F) Appearance
1
2
3
39.5 39.2 39.5 Liquid
28.4 31.5 31.9 Liquid
20
32.3
32
32.1 Ice beginning to form
31.1
30.6
28.4
30.1
30.8 Small crystals
28.8
26.6
26.5 Small crystals
30
32.3
32.3
Poke throughsheet of
32.3 ice
31.5
31.7
30.8
30.6
Poke through hard
30.4 slush
28.4
28.8
28.4 Soft slush forming
40
32.3
32.3
32.3 Almost fully solid
30.8
30.2
30.1
29.9
29.7 Hard slush
27.2
27.2
30.8
30.4
29.7
29.7
27.7 Almost no liquid left
25.6
26.6
25.7 Thick slush
17.5
12.1
18.5
16.2
17.3 Almost no liquid left
14.9 Hard slush
80
4
7.9
90
‐3.4
‐3.1
6.5 Hard, dry slush
Very hard slush, no
‐2.5 liquid
Time (min)
50 x
x
x
Frozen solid
60 x
70
x
x
Frozen solid
100
x
x
31.5 Small crystals
Poke through hard
31.3 slush
Becoming mostly
30.5 solid
Almost fully frozen
30.1 solid
x
Frozen solid
x
x
x
Frozen soid
x
x
27 Medium slush
x
Frozen solid
50%
Temperature (°F) Appearance
1
2
3
39.9 39.2 40.1 Liquid
26.1 31.7 31.3 Liquid
67%
Temperature (°F) Appearance
1
2
3
40.4 40.1 40.4 Liquid
27.4 30.2 33.2 Liquid
17.1
23.4
24.5 Liquid
17.8
21.1
23.8 Liquid
20
21.6
22.3
22.5 Liquid
18.5
20.3
22.3 Liquid
30
17.8
18.7
18.9 Soft slush
10.1
11.3
13.5 Thick liquid
40
16.7
17.1
17.8 Juicy thick slush
11.2
11.9
12.4 Thick liquid
50
14
12.2
14.2
13.7
14.4 Thick slush
13.5 Thick slush
7.2
7.2
7.9
7.7
60
70
9.4
10.4
9 Thick slush
2.5
4
‐3.2
‐0.4
‐2.5
‐2.2
7.2 Thick liquid
8.5 Thick liquid
A few small crystals
3.2 forming
Slush beginning to
‐1.1 form on top
‐7.5
‐7.5
‐7.4
‐7.6
‐7.5 Slushy and gooy
0.4 Hard slush
Hard slush, still
deformable, did not
‐7.6 freeze
Time (min)
0
10
80
90
100
0
10
0%
Temperature (°F) Appearance
1
2
3
38.8 39.5 39.9 Liquid
35.2 35.4 35.2 Liquid
8%
Temperature (°F) Appearance
1
2
3
38.8 38.8 39.2 Liquid
33.8 35.6 34.1 Liquid
14%
Temperature (°F) Appearance
1
2
3
39.3 39.5 39.7 Liquid
31 33.6 33.6 Liquid
25%
Temperature (°F) Appearance
1
2
3
39.5 39.2 39.5 Liquid
28.4 31.5 31.9 Liquid
20
32.3
32
32.1 Ice beginning to form
31.1
30.6
28.4
30.1
30.8 Small crystals
28.8
26.6
26.5 Small crystals
30
32.3
32.3
Poke throughsheet of
32.3 ice
31.5
31.7
30.8
30.6
Poke through hard
30.4 slush
28.4
28.8
28.4 Soft slush forming
40
32.3
32.3
32.3 Almost fully solid
30.8
30.2
30.1
29.9
29.7 Hard slush
27.2
27.2
30.8
30.4
29.7
29.7
27.7 Almost no liquid left
25.6
26.6
25.7 Thick slush
17.5
12.1
18.5
16.2
17.3 Almost no liquid left
14.9 Hard slush
80
4
7.9
90
-3.4
-3.1
6.5 Hard, dry slush
Very hard slush, no
-2.5 liquid
Time (min)
50 x
x
x
Frozen solid
60 x
70
x
x
Frozen solid
100
x
x
31.5 Small crystals
Poke through hard
31.3 slush
Becoming mostly
30.5 solid
Almost fully frozen
30.1 solid
x
Frozen solid
x
x
x
Frozen soid
x
x
27 Medium slush
x
Frozen solid
50%
Temperature (°F) Appearance
1
2
3
39.9 39.2 40.1 Liquid
26.1 31.7 31.3 Liquid
67%
Temperature (°F) Appearance
1
2
3
40.4 40.1 40.4 Liquid
27.4 30.2 33.2 Liquid
17.1
23.4
24.5 Liquid
17.8
21.1
23.8 Liquid
20
21.6
22.3
22.5 Liquid
18.5
20.3
22.3 Liquid
30
17.8
18.7
18.9 Soft slush
10.1
11.3
13.5 Thick liquid
40
16.7
17.1
17.8 Juicy thick slush
11.2
11.9
12.4 Thick liquid
50
14
12.2
14.2
13.7
14.4 Thick slush
13.5 Thick slush
7.2
7.2
7.9
7.7
60
70
9.4
10.4
9 Thick slush
2.5
4
-3.2
-0.4
-2.5
-2.2
7.2 Thick liquid
8.5 Thick liquid
A few small crystals
3.2 forming
Slush beginning to
-1.1 form on top
-7.5
-7.5
-7.4
-7.6
-7.5 Slushy and gooy
0.4 Hard slush
Hard slush, still
deformable, did not
-7.6 freeze
Time (min)
0
10
80
90
100
Unit 2 Lab: BCBT 100
Taste Analysis
Goals of the experiment:
• Develop scientific experiments assessing flavor
• Collect data using effective and unbiased ranking scales
• Use appropriate controls and procedures for taste-based experimental design
• Interpret rank-based flavor data using graphing and averages
• Identify sources of error in taste-based experiments
One of the main ways we assess good food is by taste. While there are many scientific devices that attempt to isolate
aspects of taste, like particular chemicals associated with flavor perception, human taste and smell cannot be replicated
in the lab. This means that human tasters are still a critical component of food-based science experiments. In this lab
you will design some simple taste-based experiments in a scientific manner.
Part 1: Developing hypotheses
A taste-based scientific experiment is not an opinion-based experiment. The goal of a taste experiment is to assess the
flavor and texture profile of a food, NOT to get people’s opinion on a food or assess the value of a particular food or
ingredient. Experiments that focus on opinions are generally social experiments that fall under marketing and
psychology, not natural science. Natural science seeks to understand what humans are processing in terms of flavor
profiles, not whether they like those flavors or not.
The scientific questions you will want to ask about taste are things like:
• How do different types of cheddar (mild, medium, sharp, and white) compare in their taste profile?
• What is the difference in taste between white bread and wheat bread?
• How does the addition of sweetener, sugar, or honey change the taste of my tea?
• What is the effect of hard water on the taste of pizza dough?
Questions to avoid in this class because they use marketing and statistical analysis techniques that we don’t cover:
• Do people prefer sharp cheddar, medium cheddar, or mild cheddar?
• Is bakery white bread better than generic white bread?
• Does tea taste better with sweeteners?
• Is making pizza dough with bottled water worth it?
To develop a hypothesis based on these questions, you will want to focus on the specific aspects of flavor you think will
be different between the foods you are testing. This is where those flavor terms (sweet, spicy, salty, bitter, sour, umami)
can come in handy, as can other terms we associate with taste and flavor (smooth, creamy, gritty, crunchy, soft, chewy,
tender, crispy, dense, airy, astringent, dry, earthy, nutty, hoppy, citrusy, minty). In general, a good tasting hypothesis will
be very specific and include a few categories of taste and feel.
Flavor wheels can help you pin down tastes you might be looking to assess. These are diagrams people have put
together to try to isolate specific types of flavors and examples of foods we connect these flavors to. There are some
generic flavor wheels and many specialty flavor wheels for developing profiles of things like coffee, chocolate, or cheese.
It also may be useful to look up the type of foods you are tasting either in your book or online and see how others have
described them as you try to pinpoint exactly what tastes and flavors you are looking for in your experiment.
Example flavor wheels:
For this lab we will keep things simple and simply look for differences in taste between a few related items. In your
applied labs (modules 3-6) you want to develop experiments that are designed to test the impact of certain cooking or
molecular processes on the taste or physical characteristics of particular foods. The cooking and molecular processes will
give you a more in-depth ‘because’ rationale or explanation statement. For now, a general reason why your foods might
be different is fine.
A few examples of taste hypotheses:
• Sharp cheddar cheese will be drier, tougher, and more sour and bitter tasting than mild cheddar because the
aging process will change the cheese.
• Wheat bread will be drier, denser, and more toasted and salty tasting than white bread because they are made
from different types of flour.
1. (1pt) Choose 2 to 3 similar foods or drinks and make a hypothesis about how the taste qualities (taste, flavor,
or texture) may differ between them. Your hypothesis should include 4 taste-based qualities that you think
you are likely to see differences in between the 2-3 foods. If you want, you can use cheese or white/wheat
breads like the examples, but choose your own taste-qualities instead!
[Insert your hypothesis here]
Part 2: Choosing appropriate assessments
Once you have a hypothesis you will need to decide on how you will determine just how gritty or sweet or bitter your
foods are. To do that, you will need to create a ranking scale that can be used by both yourself and other people to
assess the food or drink samples as you taste them. Because we are using people as the machines to measure taste, we
need to be very precise in what you are asking. Humans need very specific guidance or the feedback they give will easily
be influenced by other things (like whether they like what they are eating or not!).
Create a ranked scale for each taste or flavor you are assessing, for example bitterness on a scale of 1-5 (or 1-10, or a
different scale all together). You will need to choose how the scale corresponds to the taste (e.g. is 1 very bitter or not
bitter at all). You will also need to write a short description for each end of the scale. A comparison to several foods can
help tasters understand the specific taste or texture you are looking for them to identify. For example: Rank the
bitterness of the items on a scale of 1 to 5 with 5 being extremely bitter, like the sharp taste of very dark chocolate,
broccoli, or coffee, and 1 being not very bitter at all.
2. (2pts) Make a descriptive ranking scale for each of the four taste qualities you chose in your hypothesis by
filling in the table below:
Taste quality being
tested
Scale
Description of ranking scale
Part 3: Experimental Design: Reducing Bias and Introducing Controls
People have a difficult time separating their feelings about foods and food brands from the actual taste and qualities of
the food itself. As such, it is important to set up your study to be as concealed as possible. This means you will need to
attempt to ensure that the person testing the food is as unaware as possible of which sample they are testing. Ways to
accomplish this include removing food items from their packaging and placing them in identical containers, as well as
cutting the food samples to be the same size and shape. Make sure to label your identical containers with a code you
have written down (e.g. ‘A’ is skim milk, ‘B’ is 2% milk). If you are the one doing the tasting, it can be very useful to have
an unaffiliated 3rd party label your samples and create the code instead, and then have them keep that information to
themselves until you have finished the tastings.
In addition to reducing bias, we also want to be sure that the experiment went according to plan. You can do this by
adding a control to your tasting. This will usually mean you will want to double up on one or more of your samples. You
can then compare the results of the rankings for food you included twice to see how similar the ranking was for each.
Identical samples should have identical rankings, so if the rankings are very similar you have an indication that there is
not a lot of error in your study.
Finally, you will want to think about the number of taste testers you will need. As we are using humans to measure taste
qualities, each taster is a replicate measurement your study. Ideally you will want at least three tasters (three
replicates), if you can find them. This will make your study much more accurate and interesting to draw conclusions
from. However, if you only have access to your, yourself, and I you can still complete the experiment, just triple up on all
of your samples (while still doing your best to conceal the identity of each sample) so that you end up tasting and
ranking each item at least three times. This is not a true replicate, but will be sufficient for this class.
3. (3pts) Write down your experimental procedure. Include the specifics of the items you are testing such as the
brand and other identifying characteristics (e.g. if the cheese you are using is shredded/pre-sliced/brick). In
your procedure indicate how many tasters you are using, the strategies you will be using to conceal the
sources in your study, and what you are using for controls in your study.
[Insert experimental procedure here]
Part 4: Collecting data and Interpreting Results
You are now prepared to carry out your experiment. You will need to document this lab (and all of the rest of the labs
for this class) by taking a selfie that includes you and all of your supplies/tools as well as documentation of the
experiment itself to show that it is indeed you carrying out the lab for this class. For this experiment I would take a
picture of myself with all of the items I will be using for the taste testing, and then document the lab with a photo of the
items as they are set out for tasting to show my samples and how I have attempted to conceal and control them in my
study. This will also enable your audience (the class) to visualize exactly what you did in your experiment so that each of
us has a good understanding of your experimental design.
Once you have documented your set up, give each of your tasters your ranking description from #2 and a chart (you can
use the one below as a template) to rank each of the samples you give them.
Example ranking table you can use for collecting data (Rename with the taste qualities you are testing and add
additional columns or rows as necessary)
Taste Quality 1
Taste Quality 2
Taste Quality 3
Taste Quality 4
Ranking
Ranking
Ranking
Ranking
Sample A
Sample B
Sample C
4. (5pts) Collect all of your data. Use the data tables below to record all of the rankings your tasters provided on
their ranking sheets for each sample. Change the headings to reflect the qualities you are testing for. Don’t
forget to ‘decode’ your sample letters back to the actual products you were testing. For the average ranking
just add together the ranking from each of the tasters and then divide that total by the total number of
tasters you used. Copy and paste to add extra tables for additional samples.
Sample A
Taste Quality 1
Ranking
Taste Quality 2
Ranking
Taste Quality 3
Ranking
Taste Quality 4
Ranking
Taste Quality 1
Ranking
Taste Quality 2
Ranking
Taste Quality 3
Ranking
Taste Quality 4
Ranking
Taste Quality 1
Ranking
Taste Quality 2
Ranking
Taste Quality 3
Ranking
Taste Quality 4
Ranking
Taster 1
Taster 2
Taster 3
Average Ranking
Sample B
Taster 1
Taster 2
Taster 3
Average Ranking
Sample C
Taster 1
Taster 2
Taster 3
Average Ranking
5. Insert your documentation photos here. If insufficient or no documentation photos are provided, the lab will
receive a score of 0.
6. (5pts) Compare your averages to assess your hypothesis and look for trends by graphically representing your
data. Make a separate bar chart for each taste quality that shows the average rank for each of your samples.
Make sure your axes are correctly labeled and that each chart is labeled with the taste quality measured.
These can be hand drawn or computer generated.
[Insert images of the 4 bar charts here]
7. (4pts) Discuss your experiment.
a. What did you learn about the taste of your foods? How did your results compare to your predictions
(hypothesis)?
[Insert Answer Here]
b. Brainstorm at least one way the information you gained on the taste profile of your foods could influence
your cooking or eating in the future.
[Insert Answer Here]
c. What did you notice during your experiment that may have been a source of experimental error?
Experimental error refers to aspects of the way you carried out the experimental procedure that may
have caused your rankings to be slightly different between replicates or from other researchers who have
tested the same thing. Experimental error does not mean mistakes you made or could have made in
calculations or recording data.
[Insert Answer Here]
d. What would you do differently if you re-did this experiment?
[Insert Answer Here]
e. You have now completed a full taste-based scientific experiment. Based on what you learned, discuss a
new experiment you could do that would add to your knowledge. This shouldn’t be something you would
re-do, but rather a future direction that you are now interested in because of your experience with this
experiment. For example, in your experiment your tasters ranked skim and 2% very differently in terms of
creaminess. Based on that, you might be interested in a future experiment to compare the creaminess of
nut milks to skim and 2% milk.
[Insert Answer Here]