Wood to Wheels
Purifying Our Ethanol Solution
Lesson Introduction
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Title: Turning Wood into Ethanol
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Subject/ target grade: Seventh grade
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Duration: (4) 55 minute class period
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Setting: My classroom
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Learning Objectives:
 Students will be able to collect data on temperatures over time of the boiling liquid and of
the vapor during the distillation process.
 They will be able to accurately predict the amount of alcohol yield by relating their data
to a distillation temperature & concentration graph.
 They will be able to determine the densities of the distillation products of the distillation
process early and later.
 They will be able to compare the two densities and determine the % of ethanol in each.
 Students will be able to dilute our ethanol product to a 5% to 15% ethanol concentration
for use in our “Direct Ethanol Fuel Cell Fan”.
 Students will be able to demonstrate that they have made ethanol by burning it in a watch
glass and by using it as a fuel for our “Direct Ethanol Fuel Cell Fan”
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Michigan Content Standards: relevant science and math standards that the lesson
addresses:
S.IP.07.12 Design and conduct scientific investigations.
S.IP.07.13 Use tools and equipment (spring scales, stop watches, meter
sticks and tapes, models, hand lens, thermometer, models,
sieves, microscopes, hot plates, pH meters) appropriate to
scientific investigations.
S.IP.07.14 Use metric measurement devices in an investigation.
S.IP.07.15 Construct charts and graphs from data and observations.
S.IP.07.16 Identify patterns in data.
P.PM.07.11 Classify substances by their chemical properties
(flammability, pH, and reactivity)
P.PM.07.24 Describe examples of physical and chemical properties
of elements and compounds (boiling point, density,
color, conductivity, reactivity).
P.CM.07.21 Identify evidence of chemical change through color,
gas formation, solid formation, and temperature
change.
P.CM.07.22 Compare and contrast the chemical properties of a
new sub
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Lesson Overview:
Students will be part of an experiment in which the teacher will be running a distillation
activity using the fermented product from a previous activity. Students will be recording the
boiling and vapor temperatures and times. The teacher will collect at least two samples of the
distillation products during this activity. The samples will be weighed so that their densities can
be determined. From this data students will determine the % of ethanol in each sample. These
samples will then be used to make a 5% to 15% ethanol solution for our “Direct Ethanol Fuel
Cell Fan”. We will also be burning the samples in watch glass to compare the ethanol
concentrations by observing the amount of water droplets that are left behind.
Lesson Core
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The Guiding Question:
How can we extract our ethanol from our fermentation product?
How will we know if really made ethanol?
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Materials and Equipment Needed:
Distillation kit
Fermentation media from the fermentation activity
Safety glasses
Electrical outlet
Water Source
Sensitive electronic scale
Vapor equilibrium curve for ethanol
Watch glass
Flame source
Direct Ethanol Fuel Cell Fan from Discover Clean Energy Technologies
http://www.horizonfuelcell.com/store/bioenergy.htm
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Safety precautions:
Wear heat gloves
Handle glass with care
Keep away from open flame unless testing for ethanol in a watch glass in very small quantities
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Advanced Preparation:
Based on the sugar concentration at the start of fermentation and an assumed ethanol yield of
0.5 g ethanol / g sugar consumed, estimate the concentration of ethanol in the fermentation flasks
at the end of fermentation (when sugar is all consumed). Assemble the distillation kit and turn
on the tap water to run through the condensing column. Place the fermentation media (no more
than 300 ml) in to the 500 ml boiling flat-bottom flask with the boiling chips (5 chips).
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Background Information for Teachers:
As a result of the fermentation activity that our students did, we have ethanol mixed in with
water and other materials. Ethanol has a boiling point of 78.37 C and a specific gravity of .785.
While water has a boiling point of 100 C and a specific gravity of 1.00. Ethanol can be
identified in the distillation process by its boiling point. By looking at the boiling points,
densities, and the color of the flame produced we can d determine the % of ethanol thought the
use of the vapor liquid equilibrium curve for ethanol. In other words, early in the distillation
process we will be getting fairly pure ethanol. Later in the distillation process, we will be getting
a mix of ethanol and water. We can also identify the % of ethanol in the samples by comparing
the densities of the products. We can also test for the % of ethanol by burning very small
quantities in a watch glass and noticing the amount of water drops that remain. Our ethanol
powered fuel cell fan runs on a weak concentration of ethanol (5% to 15%). The ethanol product
will need to be diluted before using it in the fan.
In the first year I tried to run through this process in my four classes back to back. The
ethanol levels produced in the later classes was of low quality. This year I ran the activity
in my second and fourth periods one day and in my first and third periods the next day.
This allowed for cool down and clean ups between uses. We produce E 90 ethanol in all of
my classes.
Day 1:
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Engage: How will the teacher introduce the question in a way that engages the
students’ interest and builds on their prior knowledge?
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How can we separate two liquids that have different boiling points?
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“Boiling points are physical properties. Boiling is a physical change.” We will
then do a group sing of “Physical Changes” by the Science Explosion.
http://www.youtube.com/watch?v=qkwqmIJVZ20
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We will be viewing the You Tube video
http://www.youtube.com/watch?v=qkwqmIJVZ20
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The distillation process will be discussed.
Building on prior knowledge: Questions that the teacher might ask to assess the
students’ prior knowledge.
What happens to a liquid when it reaches its boiling point?
Take out your “magic glasses” that let you see molecules. This is from the “Matter &
Molecules” unit that they did in sixth grade. It is found at:
http://ed-web3.educ.msu.edu/reports/matter-molecules/
Draw the molecules of water showing liquid water as it is boiling. Include ethanol molecules
as well. Remember to draw water with Mickey Mouse ears. Draw ethanol molecules like
little dogs.
Density is _____________ / __________________
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Pre-teaching: Information that students need to know to begin exploration.
Students will need to know what the boiling point of a substance means. They will need
to know the boiling points of ethanol and of water. They will also need to know how to
determine densities of liquids.
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Explore: How will the teacher facilitate the students’ exploration of the problem and
collection of data. What questions will the teacher ask to guide students in
exploration?
We need to record the temperatures in the boiling flask and of the vapor every minute.
What type of table do you need to make?
We will also be removing and labeling two samples from the distillation process for density
analysis.
Day 2:
The teacher will:
Run Time Procedure:
 Have students wear safety glasses
 Set up the distillation unit
 Only run one lab per day. It works best to start cool and clean. (Don’t run multiple hours)
 Add boiling chips and fermentation products to the boiling flask
 Turn on the power source of the heating plate to a high setting.
 Be certain that the vapor thermometer does not touch the glass sides.
 When the liquid in the flask starts to boil, turn down the power setting to medium.
 Keep the fermentation products boiling and monitor the temperatures of both the boiling
liquid and condensing gas.
 Students will record the temperature versus time for both thermometers.
 Notice that the vapors will condense in the column with the packed glass beads and the liquid
will run back down into the flask. This is good.
 Vapor will not reach the top of the column for some minutes and you may need to adjust the
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power upward or downward to that eventually vapor reaches to top and starts to slowly
condense in the water-jacked column and drip slowly into the receiving graduated cylinder.
Students will also collect 2 ml fractions using test tubes that have a mark on them to check
the density of the product collected over time. They will measure the density of the ethanol
products.
The temperature of the condensing vapor should be approximately 78-80 degrees Celsius.
Stop collecting the ethanol product when the temperature exceeds 80-82 degrees Celsius
(when temperature rises at the thermometer measuring vapor temperature, there will be a
higher amount of water that is condensing in the column.
Turn the power source of the heating plate to a high setting.
When the liquid in the starts to boil, turn down the power setting to medium. Keep the
fermentation products boiling and monitor the temperatures of both the boiling liquid and
condensing gas.
Students will also collect 2 ml fractions using test tubes that have a mark on them to check
the density of the product collected over time.
They will measure the density of the ethanol products. The temperature of the condensing
vapor should be approximately 78-80 degrees Celsius.
Stop collecting the ethanol product when the temperature exceeds 80-82 degrees Celsius
(when temperature rises at the thermometer measuring vapor temperature, then more water
and less ethanol is in the vapor.
From the temperature of vapor at the top, students will estimate the vapor ethanol
concentration using the vapor liquid equilibrium curve.
The density measurements could corroborate the vapor temperature measurements taken for
each test tube.
The class will work in a team to collect the samples.
Students will analyze these samples and assemble the data to gain a description of the
distillation process over time in a short report or presentation.
Shut Down Procedure:
Turn off the power source of the heating plate. Allow the condensing column to cool down to
room temperature by running water. Turn the water off and disassemble the distillation kit.
Clean Up/Waste Disposal:
Pour the remainder of the fermentation media down to the drain.
Day 3:
 We will test our samples by burning a small sample of them in a watch glass. The
amount of water droplets left behind will indicate the concentration of ethanol to water.
 We will be determining the density of our samples.
 We will be using the vapor equilibrium curve for ethanol to determine the ethanol
concentrations of our samples
 We will be diluting our samples to 10% ethanol to 90% water.
 We will then use the diluted samples to run our Direct Ethanol Fuel Cell Fan from
Discover Clean Energy Technologies.
Day 4:
 Students will make a double line graph of time/boiling flask temperature/vapor
temperature
 Students will do a detailed write up which will include the procedure and a conclusion.
Explain: How will the students be to explain their data or evidence?
Students will make a double line graph for both boiling and vapor temperatures over time.
They also graph the densities of the various samples with respect to time. From that information
the students will state the % of ethanol for three different times of distillation.
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Elaboration: How will the teacher facilitate the sharing of student explanations?
What questions will the teacher ask to clarify student thinking?
In Small groups and then in class discussion, students will be asked:
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Did we make ethanol from our fermented wood? How do we know this?
What is the % of ethanol was made at three stages of the fermentation process? Provide
evidence.
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Evaluate and Lesson Closure: How will the teacher connect the student
explanations and bring out the big scientific idea.
What questions will the teacher ask to bring the big scientific idea of the lesson?
What questions will the teacher ask to assess mastery of the learning objectives?
Students will be writing a lab report with procedure data collected, evidence, tables and graphs
of the experiment.
Lesson Extension
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Assessment Options:
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Additional Resources:
Setting up a distillation unit: This is very similar to what we have.
http://www.youtube.com/watch?v=qkwqmIJVZ20
“Physical Changes” song by Science Explosion:
http://www.youtube.com/watch?v=w5Y452eiHC8