P2P
Partnering to Progress
5th grade structure and transformation of matter
July 2009 (Revised June 2010)
Begin with the following probes: Comparing Cubes and Sugar Dissolving
1
Days 1
Big Idea: Objects may be sorted into groups based on the characteristic properties
of the materials from which they are made.
FP: What categories for sorting give us the most useful information?
Learning Targets:
I can sort a set of objects into categories.
I can tell if a category for sorting is based on the material from which
something is made.
I can distinguish between sorting categories that represent characteristic
properties versus non-characteristic properties.
Word Bank: Object, use, material, property, characteristic property, noncharacteristic property, fair test
Materials needed: buckets with many objects for sorting. These should
include wooden, glass, plastic, and metal objects; objects with similar shape
or size but different colors and materials (and
Note that material and
vice versa); objects with different uses but
composition mean similar
made of the same materials; and so forth, to
things, but here we prefer the
use of the term material.
give students a broad choice of sorting rules.
Discuss possible categories for sorting: what is meant
by the following – properties, object, use, material?
Whether you use one or the
other, you should be consistent.
For this discussion, consider any materials: earth materials or manufactured
materials.
In groups, do the sorting into property groups, being sure to state a clear rule for
each sorting. Then share the rules with the class.
Are some rules creating property groups that is true for all samples of a given
material? List which these are, and brainstorm for others.
Assessment: Did/learned debriefing.
2
Day 2:
Big Idea: Objects may be sorted into groups based on the characteristic properties
of the materials from which they are made.
FP: What categories for sorting give us the most useful information?
Learning Targets:
I can sort a set of objects into categories.
I can tell if a category for sorting is based on the material from which
something is made.
I can distinguish between sorting categories that represent characteristic
properties versus non-characteristic properties.
Activity: Teacher will show students a solid rubber ball and discuss a list of
properties. Cut the ball in half and again list the properties of the halves. Continue
cutting the ball into smaller sections and continue discussing the properties.
Make a chart to list properties of each
Rubber ball
Half ball
Pieces of ball
Have students identify the properties that the samples have in common. Introduce
these as characteristic properties (properties that are the same no matter what size
the sample). Name the properties they don’t have in common (Non-characteristic
properties). **Suggestion Vocabulary Frayer Model for Characteristic property**
How could someone determine if a particular property was characteristic or not?
Ask students to devise a fair test to tell if a property was characteristic, and discuss
whether the test is fair – how can you tell?
Students will conduct fair test using various materials (aluminum foil, foam cubes,
card stock, clay, etc) to determine characteristic or non-characteristic properties.
Assessment: Did/learned debriefing.
3
Day 3
Big Idea: Some properties are characteristic.
FP: Testing whether a property is characteristic or not
Learning Targets:
I can test whether a property is characteristic.
I can tell if a test is carried out fairly or not.
Conductivity may be
new, so will need to
show how to measure
using the conductivity
testers. Also, discuss in
a general way how to
observe and measure
solubility and boiling
points.
Word Bank: Conductivity, boiling point, solubility, color, clarity, fair test
Materials needed: water, alcohol, Go temp, computer, salt, wood, plastic,
aluminum each in small and larger samples, 250 mL beakers, hot plate, scale,
conductivity tester
List the following properties and make a data chart – weight, volume, boiling point,
color, clarity, solubility, conductivity. Choose those properties that were listed
before, then add the other properties as items to test. Ask again how to conduct fair
tests, and write down student-generated rules for fair tests – include the need for
different amounts of the materials to test.
State that both liquids and solids will be tested. Students will do tests in groups,
each group doing different tests, keeping track of their data, and recording it in their
notebooks. While 3 groups are listed below, group size should be about 3 students,
and so there might be several of each of the groups.
The following liquid samples will be used: 20 mL, 50 mL, 100 mL of each of water
and alcohol, small and large wooden spheres, small and large aluminum pieces, and
small and large plastic pieces.
Group 1: Determine weight, color, and clarity of each.
Group 2: Determine volume and conductivity of each item, solid and liquid.
Group 3: Determine whether 1 g of salt can dissolve into each of the liquids.
Demo for whole class to observe (using projector): Determine boiling point of
liquids only using the GoTemps with your computer. Do not boil the alcohol
for more than several seconds, and cover the beaker with aluminum foil
immediately after the demo, to keep the fumes from filling up the room. Also
be sure there are no open flames around.
Share observations with the class, and state whether the property is characteristic
or not and the data supporting the claim.
Assessment: Did/learned debriefing.
4
Day 4
Big Idea: Measure lines are ways to compare the amount of a measurement of
different objects made of the same material.
FP: Making a measure line
Learning Targets:
I can make a measure line and use it to compare various objects.
I can make a set of rules and use them to make a good measure line.
Word Bank: Measure line
Materials needed: adding machine paper roll, cut into several 100 cm
lengths, concept cartoon showing types of weight lines (some proper some
not proper), 4 rocks with quite different masses, and labeled with their
corresponding masses, 2 g, 5 g, 25 g, and 100 g. Four sets of 4 lightweight
(e.g. cardboard) cutouts of dog biscuits, labeled as weighing 5 g, 10g, 20g, and
100g (16 biscuits total) with sticky tape on the back.
Reprise of the Darwin the Dog activity from 4th grade
Have the 4 rocks lined up side-by-side, equally spaced from lightest to heaviest, on a
blank strip of adding machine paper. Point out to the students that the weights are
all different.
Ask: “Does this arrangement show how much heavier some rocks are than others?”
“Could you think of a way to arrange them differently so that someone could tell,
just by looking, which ones are closer or further apart in weight?”
Ask a volunteer to spread the rocks along the blank strip to show how the weights of
the materials actually compare. Ask whether students agree with the result. Do
others have different suggestions?
“Is there something that can make this job of spreading out the rocks a lot easier?”
[Since the weights are known, you can use a line marked at intervals – a measure
line – instead of a blank strip of paper.]
Introduce the main question: What does a measure line show us about this set of
objects?
Explain that students will make their own measure lines so they can use them in
later activities. But first, they will learn what makes a good weight line, and then
they will apply this idea to other measurement types.
Provide an example showing several types of weight lines using the concept cartoon.
There are 5 characters: Darwin the dog, and four students. Darwin wants a weight
line that will allow him to compare the weights of his four dog biscuits. The biscuits
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weigh 5 g, 10 g, 20 g, and 100g. In the cartoon, the four students show Darwin their
weight lines.
Using volunteers, Have students place the biscuits on each of the weight lines on the
cartoon. Students should discuss in their groups about what is good and what is
problematic about each character’s weight line. Individually they should write
responses to each character on the notebook page (Dear Darwin activity).
After students finish with their responses, discuss the strengths of and problems
with each weight line, in order to prepare a set of criteria for the best possible
weight lines. Use the following dialog with the students:
Would someone read to us what you wrote to Darwin about (student 1)’s
weight line?”
Are there other points you’d like to add?
Etc.
Then ask groups of students to develop a
set of rules that would be followed to
make good weight lines. Have students
explain what makes a good weight line;
how does a rule improve a weight line.
Ask what would be a problem if a weight
line did not follow that rule.
Possible rules:

Ask, besides weight lines, what other sort
of measures could be used for comparing
different objects. Have students discuss
this in their groups, then share with the
larger class.



Marks should be evenly spaced
and the distance between marks
should represent the same
amount of weight (or other
measure.)
The line should start at zero.
The line end should have a value
higher than the largest object.
The line should show the
information clearly (e.g. a line
that is too short would not be
effective.
As students generate rules, write them on
the board, then have them copy the best
rules into their notebooks. Explain that
they will use these rules when they develop their own measure lines in later
activities.
Assessment: Did/learned debriefing.
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Day 5
Big ideas: Determine heaviness for size.
Heaviness for size is called density.
Density is a characteristic property.
FP: How can heaviness for size be determined for a given material?
Word bank: Heavy-for-size, density, characteristic property
Learning targets:
I can determine heaviness for size for a given material.
I can show that heaviness for size is the same value for a given material no
matter how much of it is present.
Materials needed: marbles, cm cubes, Large tootsie roll, 6 adding machine strips
(40 cm) per group, scales, water, 100 cc graduated cylinders
Show how to make a table for the data, leaving the final two columns unnamed for
now:
Number of
marbles
5
10
15
20
Weight of
marbles
Volume of
marbles
Each group should make the measurements: use the
scales with a small dish to hold the marbles. Check they
know how to tare the scale appropriately to determine the
correct mass. They should use the graduated cylinder
with water to determine volume by displacement, again
check to be sure they know, for example, to gently add the
marbles to the cylinder to keep water from splashing out.
Explain how to use
graduated cylinders
to measure volume
to remind students
who may be unsure.
Also should go over the idea and rules for measure lines. They will make both
weight lines and volume lines from their data.
Have the students collect the data first for the marbles only. Prepare measure lines
for their data. On each line, they should indicate where 0, 5, 10, 15, and 20 marbles
would be positioned.
Have them place their mass and volume lines side-by-side, with the data lined up,
and observe whether the data tracks well. In other words, they should recognize
that the spacing between each data set is similar between the two measurements.
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Assessment: Did/Learned: Debriefing
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Day 6
Big ideas: Determine heaviness for size.
Heaviness for size is called density.
Density is a characteristic property.
FP: How can heaviness for size be determined for a given material?
Word bank: Heavy-for-size, density, characteristic property
Learning targets:
I can determine heaviness for size for a given material.
I can show that heaviness for size is the same value for a given material no
matter how much of it is present.
Activity: Repeat this activity using the cm cubes. Repeat it exactly and have them
compare measure lines as before.
Have the students repeat this activity using the tootsie rolls. But here, they should
cut the tootsie rolls us as follows: Cut the whole thing in half, then one of the halves
cut in half, and one of those pieces should be cut in half – model this with a tootsie
roll. In the end, there should be the following sizes: a half, a quarter, and an eighth.
Then measure weight and volume on each of these three fragments. Again prepare
measure lines for the data and see if it tracks well.
Ask: which of the objects, the glass marbles, the cm cubes, or the tootsie rolls feel
like they have the largest and smallest heaviness-for-size, based on their feel. Get
answers from the students, and have them defend their feelings for this.
Assessment: Did/Learned: Debriefing
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Day 7:
Big ideas: Determine heaviness for size.
Heaviness for size is called density.
Density is a characteristic property.
FP: How can heaviness for size be determined for a given material?
Word bank: Heavy-for-size, density, characteristic property
Learning targets:
I can determine heaviness for size for a given material.
I can show that heaviness for size is the same value for a given material no
matter how much of it is present.
Add titles to the final two column for the data tables they have been creating:
weightvolume and volumeweight.
Using their calculators, they should carry out these operations for each of their data
pairs for the marbles, the cm cubes, and the tootsie rolls.
1: Do the calculated ratios indicate whether this produces an additional property
that could be considered characteristic? What evidence do you have for this?
2: Which operation is more consistent with the feeling of heaviness for size? Why is
the other operation not as helpful?
Say – dividing mass by volume is called density. This property of density
corresponds to the feeling we get of heaviness for size. Share different objects, for
example from a density set, with the students and have them tell which have greater
and lesser heaviness for size, based on their sense by feeling them, and tell them
they will measure their density in a subsequent activity.
Assessment: Did/learned debriefing.
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Day 8
Big Idea: All materials have density, and this allows us to tell whether they can sink
or float in water.
FP: What is the density of a variety of materials? How does density let us
predict whether some materials float in water and others sink in water?
Learning Targets: I can determine the density of a variety of solid materials.
-This means I can determine an object’s weight and its volume by
water displacement, and then I can calculate its density by dividing
the weight by the volume.
Word Bank: Density
Materials needed: graduated cylinders and beakers large enough to
measure the largest of the items listed below, scales, water, droppers, several
objects, including some that float and some that sink in water, such as a
variety of the density blocks, some metal hex nuts, density cylinders, iron
bars, ice cubes, and other objects as available.
Tell the students they will determine the density of several solid objects using water
displacement and weight, then dividing weight by volume. Ask – some of these
objects may float in water. What are some ways you could determine their volume
using displacement?
They should first get a sense of heaviness-for-size for each of the objects then
determine their density. They should prepare a table listing each object, its weight,
its volume, and then its calculated density.
Ask – which of these objects float in water? How do their densities compare to those
that sink in water? List on a table in front of the class data for a couple of objects
from each category, and these will be used in the next session.
Assessment: Did/learned debriefing.
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Day 9
Big Ideas: Measuring liquid density and showing that things float because their
density is less than the density of the fluid they are floating in.
FP: Do liquids possess density? Why do some things float and others sink?
Learning Targets:
I can measure the density of a variety of liquids.
I can predict whether something can sink or float in a specific liquid by
comparing densities.
Word Bank: Density
Materials needed: the same tools as before, and in addition the following
liquids: water, alcohol (ethyl alcohol or ethanol, use 95%), molasses or corn
syrup, mineral oil, vinegar, coke, diet coke; objects to float, such as plastic
and wood – choose such that some objects that sink in water (many plastics)
will float in the molasses, and others (such as ice and some woods) will float
in water, but sink in oil or alcohol.
Ask: how we might measure the density of liquids such as water, and what
differences might be needed? Why would the procedures need to be changed? Note
that the simplest way to do density of these liquids would be to place the graduated
cylinder onto a balance, tare it, add the liquid to test, and record the resultant mass
and the volume from the cylinder, and there is no need for displacement.
(Be sure they have a sense that only solids must use water displacement to
determine volume).
Set up a table as before for these liquids, record weight and volume, and have them
calculate densities.
Do any of the liquids float on water? Is their density consistent with what had been
seen on the previous session with materials that float?
Compare the densities of objects that float with the density of the liquid they are
floating in.
Compare the densities of objects that sink with the density of the liquid they sink in.
In groups, students should write a rule that predicts in all cases whether a particular
object will float in a particular liquid. Each group should share its rule with the
whole class.
Assessment: Did/learned debriefing.
12
Day10
Big Idea: Solutions are mixtures of two or more materials that may be separated
into their component parts.
FP: How can I tell that something is dissolving? How do different conditions
such as temperature affect the rate of dissolving?
Learning Targets:
I can distinguish a pure substance from a mixture.
I know that all solutions are mixtures.
I can show that when something dissolves, it is still present in the
solution and can be recovered through evaporation.
I can describe how a change in temperature or particle size will affect
the rate of dissolving.
Word Bank: mixture, pure substance, dissolving, solubility, solution, conductivity
Materials needed: 3-250 mL beakers, distilled water, plastic spoons, 3 small
(1”) pieces of aluminum foil, salt, sugar, copper sulfate, 100 cc graduated
cylinder, dropper
First day:
Direct students to do the following in
small groups where they can observe
closely and record observations in their
notebooks (especially with the crystals
at the top of the pile in the bottom of the
beaker, and water immediately above
the crystals).
Remind students that tasting
chemicals in any form during a
laboratory investigation is strictly
forbidden. Even though the chemicals
may seem friendly to our bodies, it is
always very possible some toxic
materials accidentally got into them,
so tasting would likely be harmful to
you.
Place 50 cc water into a 250 mL beaker.
Add about 1 gram of sugar and without
stirring examine the sugar at the bottom
of the water for a minute.
Read orally to the students while they are observing the mixture:
Many of the materials in this unit have been pure substances: the distilled water
you have been working with contains water only and nothing else. The alcohol you
used is 95% pure, only because it is hard to make purer. The salt contains only salt
and the sugar was only sugar. Objects composed of only one substance are termed
pure substances, and are distinguished from mixtures, which contain two or more
materials. At the beginning of this unit, you sorted materials into groups. Before
you sorted, the variety of materials present indicated it was a mixture of all those
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items. One thing scientists may do with a mixture is to separate it into all its
component parts, using the properties of those parts to make it easier to separate it.
The reason for such a separation is to make it easier to study one of the components
without all the other materials present. In any case, it is often easy to separate a
mixture, because the properties of each component are not changed by the presence
of the other components. In other words, none of the characteristic properties is
changed in a mixture.
One type of mixture is a solution. In this activity, solutions will be investigated.
While you were reading the above sections, the mixture of sugar and water were
changing. Describe in your notebooks any changes to the mixture of sugar and
water now compared to when you first looked at it.
Now stir the mixture until all the sugar particles have disappeared, if they have not
already done so. Describe what you see now. What are its state, its color, and its
clarity? Can you easily tell the difference between this and pure water? Suggest a
way to tell if it is the same or different from pure water. Suppose you would be
allowed to taste it, what do you think it would taste like?
This sort of mixture is called a solution. In a solution, there are several things to
look for:
1. A solution is generally clear.
2. In a solution, some or all of the added particles will not be seen.
3. In a solution, you can see or measure some of the properties of the
material that was added.
4. All solutions are mixtures, and there are ways to tell apart the different
components of a solution by careful examination of the properties.
5. Solutions may be separated into their component parts.
Set your beaker with the sugar-water, and again add 50 cc of water to a second
beaker. Now obtain about 1 gram of copper sulfate. Before adding it, check what it
looks like: specifically, what is its color? Now add this to the water, and stir until it
seems to vanish. Now what color is the water? Which properties of the copper
sulfate blended with the water? Are the properties of the copper sulfate present in
the solution? Set this beaker aside for now.
In the following activity, you will provide further evidence that the dissolving
material is still present after it dissolves.
Prepare a third beaker with 50 cc of water and about 1 g of salt. Stir until the salt
dissolves and note the properties of this solution.
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Using the dropper, place 2-3 drops of each solution into the middle of a piece of
aluminum foil. Set the foil aside to let the water evaporate overnight. You should
label the foil with the name of your group.
Assessment: Did/Learned/Debriefing
15
Day 11:
Big Idea: Solutions are mixtures of two or more materials that may be separated
into their component parts.
FP: How can I tell that something is dissolving? How do different conditions
such as temperature affect the rate of dissolving?
Learning Targets:
I can distinguish a pure substance from a mixture.
I know that all solutions are mixtures.
I can show that when something dissolves, it is still present in the
solution and can be recovered through evaporation.
I can describe how a change in temperature or particle size will affect
the rate of dissolving.
Students begin by observing the piece of aluminum foil which was set aside from the
previous day. Observations will be recorded in notebook and will be discussed
orally.
Activity:
The rate of dissolving is influenced by several factors: size of the particles
dissolving, whether the solution is in motion or not (for example by stirring or
swirling), and by the temperature of the solution.
In the next activity, each group will first design fair tests to determine what factors
influence the rate of dissolving, and then your group will try one of these tests for
yourselves. Depending on the size of the class, there may be more than one of each
of the following groups. 3 students per group is the recommended size.
Group 1: Particle size
Group 2: Temperature
Group 3: Solution in motion
Share the procedures you developed for a fair test with the whole class, and then
explain the conclusion you made from your results. In other words, what evidence
did you use to support your conclusion?
Assessment: Did/learned debriefing.
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Day 12
Big Idea: Dissolving is not the same as melting.
FP: What is the difference between dissolving and melting?
Learning Targets:
I can compare dissolving and melting.
I can tell what is similar and what is different about each.
Word Bank: melting, mixtures, pure substances, solutions
Materials needed: distilled water, 2-250 mL beakers, sugar, ice (made from
distilled water), 100 cc graduated cylinder, 2 1” square pieces of aluminum
foil.
In both dissolving and melting, simple observation suggests the same thing is taking
place, but is it? In this investigation, you will look at some similarities and
differences between the two.
Place 2-3 small ice chunks into a beaker with about 50 mL of water and observe
what takes place as the ice melts into the water. Of what is the ice composed? Of
what is the liquid composed? Is the final product (the fully melted liquid) a mixture
or a pure substance?
Place a spoonful of sugar into a second beaker with about 50 mL of water and
observe what takes place as the sugar dissolves into the water. Of what is the final
product (the liquid in the beaker) composed? Is it a mixture or a pure substance?
Can the solution of sugar and water be separated from each other? Can the water
the ice melted into be separated from the melted ice? Defend your answers based
on your explorations in this unit.
Test your ideas by placing a few drops of each into the middle of separate pieces of
aluminum foil. Be sure the foil is labeled! Allow to evaporate overnight, and then
check the next day. Record your observations.
Describe one way melting is different from dissolving, and one way they are the
same, based on this exercise.
Assessment: Did/learned debriefing.
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Day 13 (may take 2 days)
Big Idea: Substances can be identified using characteristic properties.
FP: How can the characteristic properties of the materials in an object be used
to identify the materials?
Learning Target:
I can identify an unknown material by using characteristic properties.
Word Bank: Forensic investigation
Materials needed: 1-qt containers with 500 mL each of distilled water,
molasses or corn syrup, 95% ethyl alcohol (ethanol), mineral oil or vegetable
oil, vinegar, salt water (dissolve 50 g into 500 mL distilled water), and a 1-qt
container with one of the liquids marked as “unknown,” scale, 100 cc
graduated cylinder, conductivity tester, aluminum foil
Teacher will incorporate a review here that
includes characteristic properties and how
they are used in the real world setting. (e.g.,
forensic investigations, CSI, etc.)
Give Students a Miranda’s Doll handout (see
attached page) and go over story with them,
not giving them any hints.
Remind students that tasting
chemicals in any form during a
laboratory investigation is strictly
forbidden. Even though the chemicals
may seem friendly to our bodies, it is
always very possible some toxic
materials accidentally got into them,
so tasting would likely be harmful to
you.
Miranda has a favorite doll. She keeps it in
a small crib in her room, but one day she noticed that the doll was missing! It had
been under a baby blanket, and there was still a bump where the doll had been, but
now the bump under the blanket was made by a bag filled with a strange liquid to
make it about the same size as the doll. She suspected one of her brothers was being
mean to her, but she has 6 brothers, so it would be hard to tell which one was the
culprit.
She called on a group of her friends to help. She explained the situation to them and
they suggested they explore the brothers’ rooms to see what they can find out. They
waited until each boy was gone, and went into the rooms and collected some items.
They found the following items in their rooms:
Brother
Aaron
Bill
Charles
Dave
Edmond
Fritz
Materials in room
Partly empty jug of water
Partly empty jug of molasses
Partly empty jug of alcohol
Partly empty jug of vinegar
Partly empty jug of olive oil
Partly empty jug of salt water
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Miranda’s friend Nancy asked why would anyone have a jug of molasses, and
Ophelia asked why, for that matter, would anyone have a jug of oil, but Miranda
simply responded that her brothers were really weird and this is the sort of thing
they do.
Petunia suggested that probably the guilty brother just used the liquid in his room
to disguise the crime, and that they should compare the properties of the liquid in
the crib to small samples of liquids from the rooms. Quinsi asked whether they
should test all of the liquids in the jugs and not just samples, but Roberta said that
the only properties that can help identify the evil brother would be characteristic
properties, and these do not depend on how much they used. The other girls all
agreed, so each set out to a different room to quietly collect small amounts of the
liquids for testing.
The friends need some help in deciding what to do next. Your group has been called
in as a consulting team to help them design tests to determine which liquid was in
the crib. You then need to carry out tests to determine the make-up of the unknown.
(Give students supplies to carry out their tests)
What is your conclusion? What reasons do you have for your conclusion? What
should you do next?
Have whole-class discussion about forensic examination of objects to determine the
make-up of them.
Assessment: Did/learned debriefing.
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Name:_________________________________________Date:_______________________
Miranda’s Doll
Miranda has a favorite doll. She keeps it in a small crib in her room, but one day she
noticed that the doll was missing! It had been under a baby blanket, and there was
still a bump where the doll had been, but now the bump under the blanket was
made by a bag filled with a strange liquid to make it about the same size as the doll.
She suspected one of her brothers was being mean to her, but she has 6 brothers, so
it would be hard to tell which one was the culprit.
She called on a group of her friends to help. She explained the situation to them and
they suggested they explore the brothers’ rooms to see what they can find out. They
waited until each boy was gone, and went into the rooms and collected some items.
They found the following items in their rooms:
Brother
Aaron
Bill
Charles
Dave
Edmond
Fritz
Materials in room
Partly empty jug of water
Partly empty jug of molasses
Partly empty jug of alcohol
Partly empty jug of vinegar
Partly empty jug of olive oil
Partly empty jug of salt water
Miranda’s friend Nancy asked why would anyone have a jug of molasses, and
Ophelia asked why, for that matter, would anyone have a jug of oil, but Miranda
simply responded that her brothers were really weird and this is the sort of thing
they do.
Petunia suggested that probably the guilty brother just used the liquid in his room
to disguise the crime, and that they should compare the properties of the liquid in
the crib to small samples of liquids from the rooms. Quinsi asked whether they
should test all of the liquids in the jugs and not just samples, but Roberta said that
the only properties that can help identify the evil brother would be characteristic
properties, and these do not depend on how much they used. The other girls all
agreed, so each set out to a different room to quietly collect small amounts of the
liquids for testing.
The friends need some help in deciding what to do next. Your group has been called
in as a consulting team to help them design tests to determine which liquid was in
the crib. You then need to carry out tests to determine the make-up of the unknown.
What is your conclusion? What reasons do you have for your conclusion? What
should you do next?
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