Science Unit Plan
Subject: Science
Grade Level: 7
Content/Theme: Separating Mixtures (subunit of Mixtures and Solutions unit)
# of Classes: 4
Daily Outline:
Day 1- Filtration- Filtration demonstration, filtration challenge and presentation
Homework: Filtration challenge assignment
Day 2- Evaporation and Distillation- Class discussion on water, distillation video, evaporation
set up
Homework: Journal entry
Day 3- Paper Chromatography- Kidnapping mystery lab, notes on chromatography
Homework: Questions from handout
Day 4- Real Life Applications- Research scenarios and present in groups to class.
Knowledge:
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Filtration
Distillation
Evaporation
Chromatography
Curricular Outcomes:
- Safely using tools and apparatus, identify and separate the components of a variety of
mixtures, using
o Mechanical sorting
o Filtration
o Evaporation
o Distillation
o Paper chromatography
- Relate the formation and separation of everyday mixtures and solutions to disciplines such as
chemistry and engineering
Skills:
1. Design and carry out an experiment.
2. Use various tools and apparatus to separate mixtures using methods of filtration,
distillation, evaporation, and chromatography
Products/Assessment Methods:
Water filtration assignment
Processes/Teaching Strategies:
Lecture
Demonstration
Group Work Assessments (formal and Co-operative Learning
informal)
Discussion
Small Group Study
Class participation (informal)
Note Taking
Experiment
Journal entry
Video
Student handout
Scenario project (end of unit
assessment)
Lesson #1: Separation of Heterogeneous Mixtures
Previous knowledge: The students have just finished a subunit introducing mixtures and
solutions. Therefore, the students already know the difference between heterogeneous
and homogeneous mixtures and the differences between solute and solvents
Curriculum Outcome Addressed:
- Safely using tools and apparatus, identify and separate the components of a
variety of mixtures, using
o Mechanical sorting
o Filtration **
o Evaporation
o Distillation
o Paper chromatography
Introduction (a check for preconceptions): Tell students that sometimes you have
mixtures that need to be separated. Ask the students for ideas on how this can be done?
(some ideas given by the students could include filtering, sifting, letting mixtures settle
out then separating, picking out larger pieces, etc.). Start a discussion by asking students
how they think groundwater got where it is, if it is pure water and why it is as clean as it
is.
(10 minutes)
Hook: Do a filter demonstration (See below for details on how to do this). Cover the
funnel/filter so that students cannot see it. The students will only see the cleaner water
coming out the bottom and into the glass. (5 minutes)
Activity: The Great Water Filter Challenge! (adapted from an experiment by Chris Piers,
teacher at Devon Middle School in Fredericton) (30 minutes)
Students will work in groups of 3-4 for this activity. For details on this activity, see the
student handout attached.
Assessments:
- At the end of class, have students present their results (filtered water) and tell the
class what materials they chose for their filter, what order they put them together,
and why. (formative assessment with no mark value) (15 minutes)
- See the attached student handout for details on a final project assessment
(summative and worth marks).
Differentiation:
This lesson is an excellent one for allowing students at all levels to participate
because of its nature (group experiment and discovery). All students on IEPs will take
part in the group work today. An effort should be made to pair more “on-grade” students
with the challenged to allow for peer tutoring opportunities.
Lesson #1 Activity: Water Filter Challenge
Objective:
The object of this activity is to construct a filter capable of separating the visible dirt from
a glass full of muddy water. The group with the cleanest looking water at the end of the
activity will be pronounced the winner.
Materials:
Students may work in groups of 3-4 maximum. Each group will receive the following
materials:
 the top half of a 2 litre plastic pop bottle (without the cap)
 200 mils of very dirty water
And a choice of any four of the following six items:
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100 ml of sand
one piece of white photocopy paper
one piece of tissue paper
mesh
100 ml of gravel
one cotton ball
Assignment (due the last day of this unit):
 Title Page: A title page is required for your project. (5 points)
 You must provide reasons for choosing each of the four materials. (10 points)
 You must provide a labeled, coloured diagram of the filter you are planning to build.
(11 points)
 Explain one thing you could have done to your filter to improve it. (9 points)
Total marks = 35
Water Filter Challenge: Marking Sheet
Title page
Reasons for choice of materials
/5
/10
(5 points for explanations of why they chose the materials, and 5
points for why they used the materials the way they did)
Labeled diagram
/11
(5 points for creating the diagram, 1 point for each of the labels up
to a maximum of 6 points. All labels must be there in order to get
full points)
Way to improve filter
/9
(Explain and rationalize a way that you believe your filter could
have been improved. 3 points improvement, 3 points for the
explanation, 3 points for the rationalization)
TOTAL MARKS
/35
Lesson #2: Distillation and Evaporation of Water
Curriculum Outcome Addressed:
Safely using tools and apparatus, identify and separate the components of a variety of
mixtures, using (209-6, 307-2)
- Mechanical sorting
- Filtration
- Evaporation**
- Distillation**
- Paper chromatography
Materials:
Salt
Containers
Water
Measuring Cups
Computer
LCD projector
Students’ Prior Knowledge and Experience:
Knowledge of what a mixture, solution, solute, and solvent are.
Common Student Misconceptions:
Water is made only of water and there is nothing else in it. Most of the water on Earth
can be used for drinking.
Hook:
Have students brainstorm in groups of 3-4 about what is in water. Have them also discuss
where our water comes from and how much of the water on Earth is able to be used for
drinking.
Have each group share their answers and write them on the Smartboard. Allow them to
discuss anything they disagree with.
Show them a picture of the Earth with percentages of salt for major bodies of water
written on it. Very little of the Earth’s water can be used for drinking. Is there anyway
that we can turn the salt water into drinking water? (15 minutes)
Main activity:
Ask students to imagine that all they have to obtain some drinking water and salt is a
large amount of saltwater. Show them the following video to explain how fresh water can
be obtained from salt water.
http://www.teachersdomain.org/resources/ess05/sci/ess/watcyc/solarstill1/index.html
(video length is about 4 minutes)
After watching the video clip, have them answer the following questions on the handout.
 Explain
how the solar still works.
 How do
you think the salt water left in the big bowl compares to the original salt water?
 What
does this imply about what happens when water evaporates from the ocean?
After answering the questions, have them think about how they could get the salt out of
the remaining water to use as table salt? (25 minutes)
After discussing their answers for the table salt question, have each student create a salt
water mixture using water and table salt. Allow them to determine how much salt and
water should be used. Have students place the bowls in a protected area outside of the
school where the sun will shine on them. Have students predict how long it will take for
their water to evaporate. (10 minutes)
Assessment:
Students will submit a journal entry on how they would obtain drinking water and salt
from salt water. They need to include a description of how they would do it and the
materials they would need. Drawings should be included as well as proper terminology
(evaporation, concentration, solute, solvent, etc.) used.
Journal entry will be marked out of 10, 5 points going to evaporation and 5 to distillation.
Each section will be broken into 2 points for the description of the process, 1 point for
materials needed, 1 point for drawings, and 1 point for labeling/using correct
terminology. (10 minutes)
Extension:
Have students mix water and salt until it is dissolved. Have them add food coloring to the
mixture to create” paint”. Have them paint a picture with the salty “paint” and leave them
to dry overnight. The water should evaporate and leave behind the food coloring and the
salt crystals on the painting. This will illustrate the concept of evaporation.
Lesson #3: Paper Chromatography- Who Done It?
Curriculum Outcome Addressed:
Safely using tools and apparatus, identify and separate the components of a variety of
mixtures, using (209-6, 307-2)
- Mechanical sorting
- Filtration
- Evaporation
- Distillation
- Paper chromatography **
Materials:
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Coffee filters
One black permanent pen/marker
Black water soluble pens/markers
Container of water
Scissors
Several glasses or plastic containers
Stapler
Tape
Pencils or skewers
Paper towel
Prepared ransom note
Teacher Preparation:
To prepare the ransom note, you need a permanent marker and a watercolor marker. (The
Mr. Sketch black marker works well for this.) Write the first part of the ransom note with
a permanent marker so the ink will not run. Write the second part of the note with the
black watercolor marker. Write the note on a piece of white paper towel. Write something
to the effect of “I have kidnapped (mascot’s name). Follow these instructions or
something terrible will happen. No COPS! Put one million dollars in the garbage can
behind the school after midnight. If this is done, (he or she) will be returned safely to you
tomorrow.” Put the bottom of the paper towel in water so the ink runs up the paper towel.
The top half should be readable in the permanent marker, and the bottom half should be
faded and the ink should be separated into its original colors. This gives the students
something with which to compare their ink samples.
Label all the markers, 1-6.
Students’ Prior Knowledge and Experience:
Writing with ink pens - the ink does not appear multicolored from a single-colored pen.
Mixing colors of paint to make other colors - you can mix colors together to make black.
Common Student Misconceptions:
Students may think that there are not other colors/pigments in black ink, while some will
think that there are different colors/pigments in the black ink.
Hook:
Place the ransom note on the board and explain that the school mascot has been
kidnapped. Tell the students that the kidnapper left a ransom note in the school’s
mailbox, but it got wet, became faded, and the ink on the paper became run. It is no
longer readable. Tell students that FBI agents are on the way, but the principal has asked
them to help solve the crime. You have narrowed the suspects down to six. You have
collected the pen each suspect was using, and now all the students have to do is
determine which pen wrote the ransom note. Put the names of the possible suspects on
the board.
Ask students if they can figure out how to tell who wrote the note. All the suspects were
found with black pens/markers. Is it possible to tell? Why or why not?
Use the students’ responses to the questions to group them into groups of 2. Try to pair a
student who has a strong misconception (such as there is no way to tell because they are
all black ink) with a student who has no misconception or little misconceptions.
(15 minutes)
Main activity:
Students will be given a coffee filter. They will need to cut them into a long and wide
strip (10-15 cm long and 5-6 cm wide).
Have students draw a line across the bottom of the strip 1-2 cm across the bottom. Mark a
spot for each ink sample at the bottom in order (1-6). Place a small dot on the line with
each marker spaced apart enough so the ink does not run onto the other samples. Use a
pencil to identify which dot belongs to which pen. Have students either fold the end of
the strip over and then staple it to form a loop to be put over the pencil, or tape it to the
pencil.
Have students get a container or glass and put a small amount of water in the bottom. Use
the pencil to hang the strip in the container. It is important that the water does not touch
the ink. Allow the water to soak up the strip and watch what happens to the ink drop. This
process will take about 10-15 minutes. During this time have students observe their strip
and write what they see happening.
Let the strips dry and tape them on a sheet of paper as a record of the different pen types.
Have students compare their ink samples to the one used on the ransom note. They
should be able to identify the kidnapper from this. (35 minutes)
At this point, give students the following information: The water soaks up into the paper,
meets the sample of ink and dissolves it. As the water continues to soak through the paper
it leaves the colour particles behind—heaviest first, lightest last. Each ink gives a unique
pattern, almost like a fingerprint.
Uses of chromatography
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Pharmaceutical Company: determine amount of each chemical found in new
product
Hospital: detect drug or alcohol levels in a patient’s blood stream or urine.
Law Enforcement: to compare a sample found at a crime scene to samples from
suspects
Environmental Agency: determine the level of pollutants in the water supply
(10 minutes)
Assessment:
Have students answer the following questions on the worksheet for homework.
1. Draw your chromatograph and label it.
2. Who kidnapped the mascot? How do you know?
3. Were the inks used in the pens a mixture? Explain how you were able to
determine the answer to this question.
The inks in the pens were a mixture because they could be separated easily. The different
colors in the inks showed that the inks were made up of more than one component. The
different colors traveled at different speeds up the paper towel, resulting in the rainbow
patterns of the different inks. This is a physical property of the ink components and the
ink samples.
4. Were the inks in the different pens all the same? Explain how you know the
answer.
The inks in the different pens were different because the patterns of the ink samples were
very different. Some of the samples had many colors and some did not have many colors.
Every ink sample separated differently.
5. Why did the ink move up the coffee filter?
The ink moved up the paper towel because of the water being absorbed into the paper
towel. It worked as a solvent and separated the ink into its component colors.
Group members: _______________________________________
1. Draw your chromatograph and label it.
2. Who kidnapped the mascot? How do you know?
3. Were the inks used in the pens a mixture? Explain how
you were able to determine the answer to this question.
4. Were the inks in the different pens all the same? Explain
how you know the answer.
5. Why did the ink move up the coffee filter?
BONUS
Why did one of the ink spots not move?
Lesson #4: Unit assessment: Development of strategies for separating
mixtures given realistic scenarios
Identification of student preconceptions: Not applicable as this class is used for subunit
assessment.
Hook: Show the students the video discussing a method for cleaning up oil spills
(separating oil from water) at the following link and then discuss some other methods that
might be used to clean up oil spills (5 minutes):
http://www.youtube.com/watch?v=CfTUC6oYt0U
Curriculum Outcome Addressed:
 Relate the formation and separation of everyday mixtures and solutions to
disciplines such as chemistry and engineering (109-10).
Introduction: Explain to the students that today’s lesson will help them apply the
knowledge they have accumulated over the past 3 days.
Activity: Separate the class into 7 separate groups and assign each of them to one of the
scenarios provided at the end of this lesson plan. The groups will be responsible for:
 Coming up with a solution for their scenario (i.e., how to separate the mixture
involved).
 Researching real-life examples of where that particular method of separation is
used (this can be done with internet access).
 Present these results to the rest of the class. (final 25 minutes of class)
At the end of class, each group will have 3 minutes to present their scenario, their
proposed solution to their scenario, and the results of their research. Additionally, each
group must identify the mixture in their scenario as either heterogeneous or a
homogeneous, and explain how they know that.
Differentiation:
Students of all cognitive levels will participate in these assessment activities.
However, group formation and assignment of scenarios should be done strategically. The
scenarios below are roughly listed in order of expected difficulty (least difficult to most
difficult). Expected difficulty level is based on the material presented in class. Students
should be grouped so that the more difficult scenarios can be tackled by the more creative
and imaginative students.
Mixture Separation Scenarios (taken from the Manitoba’s science curriculum):
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Scenario A: Pens were confiscated from three people suspected of forging a
signature. How could one determine which pen was used to forge a signature on
the given document? (Use chromatography.)
Scenario B: You are stranded on a deserted island in the Pacific Ocean. There is
no fresh drinking water, only salt water from the ocean. How could you obtain
drinking water? (Distill the water.)
Scenario C: A community by the ocean would like to establish a small business
that sells salt and pepper. Farmers are already growing peppers to be dried and
used in the business but there are no salt mines within the vicinity. Someone has
suggested obtaining the salt from the salt water of the ocean. How would this be
done? (Evaporate the water and collect the salt that remains.)
Scenario D: A person would like to make a glass of fresh pulpless orange juice.
What method could the person use? (Strain and filter the juice.)
Scenario E: A gardener would like to use some soil from the backyard to start
some seeds but there are a lot stones in it. How could the stones be removed?
(Use screens for sifting.)
Scenario F: Minute metal shards have fallen onto the sandy floor of a workshop.
How could the owner clean the sandy floor of the dangerous metal pieces? (Use a
magnet.)
Scenario G: To improve the icy road conditions, a sand-salt mixture has been
used on the highways all winter. The spring cleanup crew has scooped up the
mixture and would like to use the sand for road construction but the workers must
first remove the salt. How could this be achieved? (Add water to dissolve salt and
decant liquid.)
Assessment Rubric (Total Points = 40):
Scenario
Solution (10
points)
Group
Participation (10
points)
Research (10
points)
Presentation (10
points)
Poor
Good
Very Good
Excellent
Students did not
correctly identify
the scenario
mixture as
homogeneous or
heterogeneous and
did not develop a
reasonable
solution to their
scenario. (0-1)
Some group
members did not
actively participate
in the assignment.
(0-1)
No real-life
examples were
identified where
the mixture
separation method
was used. (0-1)
Students correctly
identified the
scenario mixture as
homogeneous or
heterogeneous, but
did not develop a
reasonable solution
to their scenario.
(2-4)
Students correctly
identified the
scenario mixture as
homogeneous or
heterogeneous,
developed a
reasonable solution
to their scenario.
(8-10)
Presentation
disorganized and
difficult to
understand. (0-1)
Significant
portions of the
scenario solution
and research
results were not
presented in a clear
and concise
manner. (2-4)
Students
developed a
reasonable solution
to their scenario,
but did not identify
the scenario
mixture as
homogeneous or
heterogeneous. (57)
All members
participated, but
division of labor
was not well
balanced. (5-7)
At least one reallife example was
identified where
the mixture
separation method
was used and a
detailed
description was
given on how it is
done. (7-10)
Most of the
scenario solution
and research
results were
explained clearly
and simply.
Completed near
the allotted time.
(5-7)
Participation from
some members
was minimal. (2-4)
One real-life
example was
identified where
the mixture
separation method
was used. (2-6)
All group members
participated
equally in the
assignment. (8-10)
More than one
real-life example
was identified
where the mixture
separation method
was used. (2
BONUS MARKS)
Scenario solution
and research
results were
explained clearly
and simply.
Presentation
completed within
allotted time. (810)