Applying the Scientific Method: Yeast Dough Lab
Materials:
• flour (white or wheat)
• water
• yeast
• 15 and 50ml conical tubes
• transfer pipet
• glass stir rod
• optional: salt or sugar
Procedure:
Design an experiment:
Use the available materials to design an experiment involving the rise of a yeast
dough. You could compare the rise of dough made with wheat vs. white flour, test
the effect of water temperature on rise, test the effect of addition of measured
amounts of salt or sugar or extra yeast, etc. Be sure to choose only a single
variable to manipulate.
Here is a good baseline mixture, to use as a control (The following will be added to
a conical tube, mixed together with a stir rod, and incubated at room temperature.)
• 10mL white flour
• 1/8 tsp. yeast
• 6mL warm water
Our controlled:
10mL white flour
• 1/8 tsp. yeast
• 6mL warm water
Our experiment:
10mL white flour
• 1/8 tsp. yeast
• 6mL cold water
Give the following:
▪ A question you can answer using the materials available:
Does water temperature affect the rise of yeast dough?
▪ A testable hypothesis (tentative answer to your question):
Warm water allows a greater rise in yeast than cold water.
▪ A detailed description of the experiment you will perform to test your
hypothesis:
We are first going to add the white flour and the yeast into the mixture. Next, we will add
the cold water to see the difference in rise and what will occur. In the hour of watching
the rise, we will write down the difference we see. The dough volume will be different
between the water temperatures.
Explain which variable you are planning on testing (i.e. the manipulated
(independent) variable?):
We are manipulating the water temperature. One will be normal warm water, and then
testing will be cold water.
Give a list of conditions that should be kept the same between the control and
experimental groups:
The yeast amount
white flour amount
Identify what will be measured (the responding (dependent) variable) and briefly
explain how it will be measured:
we will use mL to show the difference in rise between using cold water vs. warm water
(independent). Independent variables are the water, and the dependent variable is the
dough rise outcome.
Responding variable: the rise of the yeast responding to the water temperature
How it will be measured:
In mL, how much the dough will rise will be measured.
Perform the Experiment:
• Set up your experiment using the materials provided.
• Take measurements every 10 minutes for 1 hour.
• Record your data in a table, below.
Write up your experiment:
• Graph your results (time on the X axis, volume of dough on the Y; both
experimental and control data on the same graph). This can be done neatly by
hand on graph paper, or using Excel.
• Briefly (one paragraph) explain the experiment you performed; be sure to explain
how the control group differed from your experimental group.
• Briefly (one paragraph) explain the answer you found to your question (your
conclusion from the experiment) and tell whether it supported your hypothesis.
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Experiment explained:
In our experiment, we use the same amount of white flour and the same amount of yeast vs. the
temperature of water, and its effects on the rise. We first added the flour and the yeast to both
tubes. We used 10 mL of flour and ⅛ tsp of yeast in each. Next, we added the water to each
tube. One tube had warm water, and the other had cold water. Both were the same amount of
water at 6mL. The control group is warm water, and our experiment is on the effects of cold
water/ the outcome. The dependent variable is the rise, while the independent variable is the
water temperature.
Answer and outcome:
We found that over time, the warm water affected the dough's rise differently. The cold water
barely let the yeast rise, while the warm water allowed the yeast to rise. In between the 10
minutes, the warm water increased about 2mL each time. While for the cold water, the yeast
rised barely up to 17mL with not many jumps until the last 30 minutes. The difference in the end
came out to be 7 mL. The warm water test tube had dough that rised normally, while the cold
water did not let the yeast to rise. It supported my hypothesis that warm water allows the yeast
to rise and the dough to become higher in mL.
Starting minutes: warm water: 14.5 mL cold tube: 10mL
10 minutes: warm water: 20 mL cold water: 11mL
20 minutes: warm water: 22mL cold water: 12 mL
30 minutes: warm water: 24mL cold water: 17 mL
Graph