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Mixtures and Solutions: Particle Theory of Matter

Science Resource Package: Grade 7

Mixtures and Solutions:

Particle Theory of Matter

New Brunswick Department of Education

September 2009

Acknowledgements

The Department of Education of New Brunswick gratefully acknowledges the contributions of the

following groups and individuals toward the development of the New Brunswick Science

Resource Package for Grade 7 Mixtures and Solutions: Particle Theory of Matter:

The Science Resource Package Development Team:

• Chris Piers, School District 18 • Grant Williams, School District 18

Science East:

• Michael Edwards, Director of Programming • Karen Matheson, Director of Education

Kathy Hildebrand, Learning Specialist, Science and Mathematics, NB Department of Education

Science Learning Specialists and science teachers of New Brunswick who provided invaluable input and feedback throughout the development and implementation of this document.

Note that at the time of posting, all URLs in this document link to the desired science

content. If you observe that changes have been made to site content, please contact

Kathy Hildebrand [email protected], Science Learning Specialist, at the

Department of Education.

2009

Department of Education

Educational Programs and Services

mailto:[email protected]

TABLE OF CONTENTS

RATIONALE ........................................................................................................................................................ 1

BACKGROUND INFORMATION ....................................................................................................................... 3

PRIOR KNOWLEDGE: ................................................................................................................................................. 3

COMMON MISCONCEPTIONS: .................................................................................................................................... 3

DID YOU KNOW? ....................................................................................................................................................... 3

INSTRUCTIONAL PLAN .................................................................................................................................... 5

ACCESS PRIOR KNOWLEDGE ................................................................................................................................... 5

1ST

CYCLE .................................................................................................................................................................. 6

Separating Mixtures Activity ............................................................................................................................. 7

Reflection: Class Discussion ............................................................................................................................ 9

Reflection: Individual ........................................................................................................................................ 10

Think like a scientist ......................................................................................................................................... 10

2ND

CYCLE ............................................................................................................................................................... 11

Heterogeneous or Homogeneous Activity .................................................................................................... 11

Reflection: Class discussion ........................................................................................................................... 14

3RD

CYCLE ............................................................................................................................................................... 15

Activity – Smaller than the eye can see ........................................................................................................ 15

Activity – Matter’s Particles ............................................................................................................................. 16

Reflection: Class discussion ........................................................................................................................... 16

Reflection: Journal ........................................................................................................................................... 17

SUPPORTING CLASS DISCUSSION ............................................................................................................. 19

MATERIALS LIST ............................................................................................................................................. 21

STUDENT VERSION OF OUTCOMES ........................................................................................................... 22

SEPARATING MIXTURES ............................................................................................................................... 23

HETEROGENEOUS OR HOMOGENEOUS ACTIVITIES ............................................................................. 24

MATERIALS: ..................................................................................................................................................... 24

OBSERVATION CHART SHEET .................................................................................................................... 25

CHECKLIST SHEET ......................................................................................................................................... 26

OBSERVATION CHECKLIST .......................................................................................................................... 27

STUDENT RECORD ......................................................................................................................................... 28

1


New Brunswick Science Resource Package: Grade 7

Rationale

This resource package models current research in effective science instruction and

provides an instructional plan for one topic selected from the Grade 7 Atlantic Canada

Science Curriculum. This curriculum includes STSE (Science, Technology, Society and

Environment) outcomes, Skills outcomes, and Knowledge outcomes – all of which are

important for building a deep understanding of science and its place in our world.

As has been true of our ancestors, we all develop “explanations” about what we observe

which may or may not be valid. Once ideas are established, they are remarkably

tenacious and an alternate explanation rarely causes a shift in thinking. To address

these misconceptions or alternate conceptions, students must be challenged with

carefully selected experiences and discussion.

A key part of this instructional plan is accessing prior knowledge. It is recorded in a

way that it can and will be revisited throughout the topic. The intent is to revise, extend,

and/or replace students’ initial ideas with evidence-based knowledge.

Science is not a static body of facts. The process of exploring, revising, extending, and

sometimes replacing ideas is central to the nature of science. Think of science as an

ongoing evidence-based discussion that began before our time and that will continue

after it. Science is often collaborative, and discussion plays a key role. Students’

learning of science should reflect this as much as possible.

The intent of this instructional plan is to encourage a constructivist approach to

learning. Students explore an activity, then share, discuss and reflect. The telling of

content by the teacher tends to come after, as an extension of the investigation (or

experience) explored by the students.

The learning is organized into cycles. The partial conceptions and misconceptions are

revisited in each cycle so that students’ ideas will be revised. Each cycle will result in

deeper and/or extended learning.

2



Hands-on activities are part of the instructional plan. Inquiry activities tend to be most

structured in the first cycle. The teacher provides the question to investigate and gives a

procedure to follow. In subsequent cycles, less structure tends to be given. For

example, students may be given a question and asked to develop an experimental plan

which they then implement. The goal is to move towards open inquiry in which

students generate a testable question, develop an experimental plan using available

materials, implement the plan, record relevant observations, and make reasonable

conclusions. The included activities are meant to start this journey.

Discussion and written reflections are key parts of the lessons. Discussion (both oral

and written) is a vehicle that moves science forward. For example, when scientists

publish their evidence and conclusions, other scientists may try to replicate results or

investigate the range of conditions for which the conclusion applies. If new evidence

contradicts the previous conclusions, adjustments will be required. Similarly, in this

instructional plan students first do, then talk, then write about the concept. A section on

supporting discussion is included in this resource package.

Assessment tasks are also included in the instructional plan and assess three types of

science curricular outcomes: STSE, Skills, and Knowledge. These tasks are meant to

be used as tools for letting the teacher and the students know where they are in their

learning and what the next steps might be. For example: Has the outcome been met or

is more learning required? Should more practice be provided? Is a different activity

needed?

When assessment indicates that outcomes have been met, it will provide evidence of

achievement. This evidence may be sufficient and further formal testing (paper-pencil

tests) may not be required to demonstrate that outcomes have been met.

3



Background Information

Prior Knowledge:

In grade five students studied a unit on properties and changes in materials. They would

have experience:

observing and describing physical properties of materials

describing properties of solids, liquids, and gases

identifying and describing physical changes

identifying and describing chemical changes

Common Misconceptions:

Student ideas concerning matter being made of small particles will be unclear.

Individuals may have very different misconceptions about small bits.

There could be some confusion between the smallest unit of life, the cell, and the

smallest unit of matter, the atom.

When thinking about the word “mixtures”, students may only think about chemistry and

mixing chemicals as opposed to things they may use and see every day.

Students may think that a material is called a “mixture” when the different parts are

evident to the eye. In fact, some heterogeneous mixtures may appear as if they are

“solutions” (e.g. milk, orange juice...)

Did You Know?

Properties: characteristics or attributes used to describe matter (such as colour, odour,

and density)

Mixture: made up of two or more different types of materials

Mixtures can be heterogeneous: made up of parts that retain their own properties.

Taking multiple samples from different locations within a heterogeneous mixture will

result in non-identical samples.

Mixtures can be homogeneous – are the same throughout and the different parts are

combined in a way that there is one set of properties. Taking multiple samples from

different locations within a homogeneous mixture will result in identical samples.

Homogeneous mixtures are called solutions.

4



Pure substances: are composed of only one type of particle

matter

mixtures pure substances

e.g. sugar

heterogeneous homogeneous calcium carbonate

water

Particle Theory

The particle theory of matter says that all matter consists of many, very small particles

which are in a constant state of motion. The particles might be molecules, atoms or ions.

The behaviour and properties of materials can be explained by using a particle model

which helps us visualize what is happening on a very small scale. Models help us

understand, but should also be recognized to have limitations.

Solids Liquids Gases

The particles are held close together The particles are in fixed positions but they do vibrate

The particles are fairly close together with some attraction between them The particles are able to move around in all directions but movement is limited by attractions between particles

The particles have little attraction between them The particles are free to move in all directions and collide with each other and with the walls of a container and are widely spaced out

5



Instructional Plan

Access Prior Knowledge

Ask: What are mixtures? What are not mixtures? List some mixtures. List substances

that are not mixtures (pure substances).

Have students discuss these questions in pairs or small groups using a placemat activity

and record their ideas. To do a placemat activity, students fold a sheet of paper into

halves or fourths (depending on number of students in the group). All at the same time,

each student puts what they think and know in their section of the sheet. They can write

in words and/or draw pictures. Students share their ideas with other members of their

group.

Placemat: folds shown with dotted lines

Each student writes their ideas in

one section of the sheet.

Have students share their answers with the class. Make a large class T-chart so ideas

may be revisited in other lessons. These ideas may include facts, characteristics and

examples of mixtures and pure substances. (Accept misconceptions; do not attempt to

correct students at this time. Students may, however, convince each other to change

their minds. Look at the tips for facilitating class discussion on pages 19-20)

mixtures not mixtures

Provide labels for students to look at the ingredients of various products (for example:

food, clothing). Items with more than one ingredient are mixtures; if there is only one

ingredient then the item is a pure substance. These labels can be added to the T-chart.

Post student versions of curricular outcomes on chart paper (see page 22).

Inform students that these outcomes will be addressed over the next portion of

the unit. Point out to students which outcomes are being addressed in each

activity.

6



1st Cycle

Have a class discussion: Ask: Why would people want to separate mixtures?

What mixtures get separated in real life and how are they separated?

Have students write a journal entry about the separation of mixtures in real life

Some examples of separating mixtures in the real world include:

sorting change to roll coins

to obtain desired minerals from mined ore

filtering and treating water/sewage

cleaning up oil spills in the ocean

sorting recyclable materials

separating blood into plasma, red blood cells, and so on

Assessment:

Can students determine real life situations where it is useful to separate mixtures?

Curriculum Outcomes

109-7 Identify different approaches taken to answer questions, solve problems, and make decisions.

112-7 Provide examples of how science and technology affect their lives and their community.

209-6 Use tools and apparatus safely. 210-16 Identify new questions and problems about mixtures that arise from what is

learned. 307-2 Identify and separate the components of mixtures.

7



Separating Mixtures Activity

The focus of this activity is different methods of separating mixtures and introducing the

definitions of heterogeneous and homogeneous mixtures.

Materials:

Different tools for separating each mixture such as tweezers, plastic cups, forks,

magnets, filter paper, bowls, colanders, and spoons.

Different types of mixtures of two or three items

Possible separation methods and examples of mixtures:

Separation method Example of mixture

Colander

or containers with different sized holes

Rice and beans

Marbles and tennis balls

Cheerios® and Rice Krispies®

Scooping with slotted spoons or forks Styrofoam peanuts and water

Magnetism Metal nuts/washers and rubber bands

Iron filings and water

Decanting (carefully pouring a solution

from a container in order to leave the

precipitate in the bottom of the original

container)

Cooking oil and water

Evaporation Salt and water

Floating, dissolving, static (using a

balloon) Salt and pepper

Filtration Sand and water

Manually (by hand) Different colour or size beads

Different colour bread ties

Not easily separated Salt and sugar

Vinegar and water

Students working in small groups are presented with three or four different

mixtures from the list in the materials section. (Each group should have 1 or 2

different mixtures in common with other groups, and 1 or 2 mixtures which are

unique to them. This will allow some comparison during the post activity

discussion.)

Students are first asked to examine the mixture, writing down their descriptions

of the properties of the mixture – what do the constituents of the mixture looks

like, what shape are they, what colour are they, are they hard or soft, etc.

8



Students need to be made aware

that inability to separate a mixture

is not being unsuccessful.

Negative results give important

information to scientists and

should not be considered a waste

or failure.

Using a three quarter foldable, each student will draw a picture and label the

parts for one of their mixtures (with visible components). Make the foldable by

folding a sheet of paper into fourths and cutting the top left quarter off. (see

diagram)

After cutting off the top left quarter,

students will draw a picture and label the parts for

this same mixture.

Students should attempt to separate each mixture in

turn, using whatever method they feel will be most

successful. They can use some of the apparatus

provided or devise their own method, although

these should be discussed with a teacher prior to

using them for safety reasons.

Students indicate their separation method and draw the different components of

the separated mixture under the flap of the folded paper. Both the back of the

flap and the bottom fourth may be used.

For all their assigned mixtures, students should record what method(s) they used

for separation and how successful their attempts were.

Compared to the uses of the original mixture, what is different about the ways we

can use the separated components of the mixture? Explain.

9



Options for storing foldables:

in a large zippered plastic bag. The bag can be hole-punched and put inside

a duotang or binder. A strip of wide tape folded over the left edge of the bag

before punching the holes will keep the bag from ripping.

glue into notebooks or duotangs

display them on bulletin boards

Reflection: Class Discussion

Students will share which mixtures they had and the method used to separate their

mixtures with the other groups. Taking the mixtures one at a time, ask questions like:

Did your group have this mixture? How did you separate it? Did anyone separate it a

different way? Were any other mixtures separated using that method?

Revisit the T-chart on mixtures (see page 5). Ask: Are there any items that should be

added to or revised. Is there other information we could add? Remind your class about

respectful discussion. See the tips on page 19-20.

Question for the class: Can everything be separated?

This video clip made by NB grade 7 students describes distillation as a method of

separating a mixture https://studycasts.wikispaces.com/Distillation

Assessment: During student activity, make notes on outcomes (or parts of outcomes) you observe being addressed. Process skill outcomes are part of the curriculum and should be assessed. Using the observation chart or the checklist (on page 25-27) on a clipboard may be helpful to you. This is sometimes called clipboard cruising. Develop your own code for quick notes.

A suggested code: √ observed and appropriate, WD with difficulty, RTT refused to try, A absent.

This chart may be used on multiple days, using a different coloured pen or pencil each day and putting the date in the corner. You may not have a symbol or note for every child every day. Some teachers like to focus on a group or two each time. However you choose to make note of your observations, you will always have a sense of who you need to take more notice of and who might need extra support. The information will also help you when it is reporting time.

https://studycasts.wikispaces.com/Distillation

10



Reflection: Individual

After discussion, have individuals write a journal entry. Can everything be separated?

Explain.

Think like a scientist

Asking good questions is an important skill in science. Initially students will need

support. Model the skill with the whole class and students will begin to have the

confidence to contribute. After some practice, students will be able to generate

questions successfully individually.

Present students with a situation and ask them to generate questions that could be

investigated scientifically. (These situations and questions do not have to be limited to

those that can be done in a classroom.)

Situation:

Canadian Blood Services collects donations of blood from the public and makes

blood products available to hospitals. In some cases whole blood is not needed

and patients are given platelets, red blood cells, plasma, or another component

found in blood.

Write a question concerning the separation of blood into useful components that

could be investigated scientifically.

For example:

Would a coffee filter separate one or more components from the rest of blood?

What is the ratio of the different components in blood?

Assessment:

Journal entries should not receive a score or mark. A positive comment followed by a

question to refocus attention or suggest the next step in learning is very effective.

Read journal entries to determine students’ understanding of mixtures - consist of two

or more components, components may be easy to distinguish or not, and the

properties of the components may make them easy to separate or very difficult to

separate.

11



2nd Cycle

Introduce the idea of heterogeneous and homogeneous materials.

Heterogeneous mixtures – more than one type of material observable in the

mixture and not uniformly spread throughout.

Homogenous– appears to be one substance spread uniformly throughout. One

set of properties will describe all components of the mixture.

This video created by Grade 7 students may be helpful

https://studycasts.wikispaces.com/Homogeneous+Mixtures

As a class, and using the drawings from the last activity, sort the mixtures from Cycle 1

into heterogeneous and homogeneous mixtures. (If students could observe the

components and separate them, the mixtures would be heterogeneous.)

Make a list of products used every day in the kitchen. (dish soap, hand soap, cooking oil,

lemon juice, ketchup, salsa).

Ask students to classify the items as homogeneous or heterogeneous.

Heterogeneous or Homogeneous Activity

In small groups:

Have students work in groups to explore and classify the following (or mixtures/solutions

similar to these) as homogeneous or heterogeneous.

Curriculum Outcomes

209-3 Use instruments effectively and accurately for collecting data. 209-6 Use tools and apparatus safely. 307-1 Distinguish between pure substances and mixtures, using the particle model of matter. 307-2 Identify and separate the components of mixtures.

https://studycasts.wikispaces.com/Homogeneous+Mixtures

12



Materials:

At least 3 of: orange juice with pulp; chicken noodle soup; homogenized milk;

salsa; relish; jam; soda water; chocolate chip cookie.

Plus at least 3 of: shampoo; toothpaste; mustard; Kool-Aid; ketchup; dish

detergent.

Glass or clear plastic containers

Magnifying glasses

Microscopes or dissecting scopes

Dropper

Slides and cover slips if available

Flashlight

For each sample, the students:

make observations without any optical aid and sort the containers into 2 groups

make observations using a hand magnifier. Are there any samples they would

reclassify?

Using microscopes (if available), have the students decide if there are some samples in

the solutions group that they should look at more closely. Are there any samples they

would reclassify?

Assessment:

On observation chart (or other record), note how students are performing on the skill

outcomes.

13



To record their results, students could use a layered book.

Layered book instructions:

Fold one sheet of paper

unevenly so there is a flap

Fold a second sheet more

unevenly

Place the folds inside each

other to create 4 layers.

Then cut up the middle of

the top 3 layers to create

flaps.

The top flaps can be labelled: heterogeneous mixtures,

homogeneous mixtures (solutions).

The second layer would list the mixtures on the

appropriate side using observations with the eye –

drawings or reasons for classifying the mixture could be

required

The third layer would list the mixtures on the appropriate

side using a hand lens - drawings or reasons for changing

a classification could be required

The fourth layer would list the mixtures on the appropriate side using the

microscope - drawings or reasons for changing a classification could be required

Note: Remind students that reclassifying an item when seen under higher

magnification doesn’t mean they were wrong the first time. As technology improves

and we are able to see smaller and smaller things, scientists’ understanding changes.

This sometimes results in changing models and theories.

14



Reflection: Class discussion

Facilitate a discussion about what students observed and their reasoning for

reclassification of mixtures as greater magnification was used.

Here is a video clip made by grade 7 students about the differences between

heterogeneous and homogeneous mixtures

https://studycasts.wikispaces.com/Beverage+Lab+-+Homogeneous+and+Heterogeneous



respectful discussion. The tips on pages 19-20 may be helpful.

Assessment: Mixtures foldable can be collected. Note classification of materials and whether observations with increased magnification resulted in changes.

https://studycasts.wikispaces.com/Beverage+Lab+-+Homogeneous+and+Heterogeneous

15



3rd

Cycle

Activity – Smaller than the eye can see

1. In small groups, have students brainstorm and record a list of the smallest things

they can think of. Each group can organize their items from largest to smallest. You

could have students print ideas on index cards or on pieces of paper with markers.

(These can be tacked to a bulletin board as they are shared.)

2. Then as a whole class, share one item that is the “smallest item” from each group

(round robin style) and record on the board or on chart paper. As each item is

named, decide where the item fits in the list of largest to smallest. Those items that

no other group has can earn that group a point.

Note: Even if students say atoms or molecules as their first item, work to elicit items of

different sizes to try to help students conceptualize how small particles are. Parts of the

atom, such as protons, electrons and/or neutrons may also be named, but not all

students will be able to visualize these. This activity also provides an opportunity to

discuss how the cell is the smallest unit of life and that it also is made of smaller

particles.

Option: Powers of 10 video – famous video to help demonstrate size and scale. It can

be found on YouTube at http://www.youtube.com/watch?v=A2cmlhfdxuY but if that link

is removed at some point, the official website is www.powersof10.com where the video

can be watched but it requires an e-mail address registration to be accessed. There is

no charge at this time.

Curriculum Outcomes

307-1 Distinguish between pure substances and mixtures, using the particle model of matter.

307-3 Describe the characteristics of solutions, using the particle model of matter.

http://www.youtube.com/watch?v=A2cmlhfdxuY

http://www.powersof10.com/

16



Activity – Matter’s Particles

Revisit a variety of the heterogeneous and homogeneous mixtures (solutions) from the

first two cycles.

To contrast mixtures and pure substances:

1) a) Refer to the diagram students drew in Cycle 1 of one of their mixtures and the

separated components (page 8). Introduce students to the particle model of matter

by having them imagine the particles (molecules). Choose one of the heterogeneous

mixtures and ask students to re-draw and label the diagram of their “chosen”

solution from Cycle 2 showing how the particles are distributed. This diagram

should have different types of particles spread randomly and irregularly throughout.

b) Now have them re-draw a diagram of their separated components showing how

the particles are distributed. This diagram should have one type of particle.

Students should use the terms heterogeneous, mixture and pure substance.

To contrast homogeneous and heterogeneous mixtures:

2) Choose one of the heterogeneous mixtures from Cycle 2. Draw and label a diagram

of the heterogeneous mixture showing how the particles are distributed.

3) Choose one of the homogeneous mixtures (solutions) from Cycle 2. Draw and label

a diagram of the solution showing how the particles are distributed.

Reflection: Class discussion

Have a class discussion highlighting the types and distribution of particles in the pure

substances and heterogeneous and homogeneous mixtures.



respectful discussion.

Assessment:

Student diagrams -

For heterogeneous mixtures, is there more than one type of particle identified and are

the particles spread randomly throughout the mixture?

For homogeneous mixtures, is there more than one type of particle identified and are

the particles spread evenly throughout?

17



Reflection: Journal

1. What characteristics are necessary for a material to be considered a pure

substance?

2. What characteristics are necessary for a mixture to be considered a heterogeneous

mixture?

3. What characteristics are necessary for a mixture to be considered a homogeneous

mixture (solution)?

Possible Extensions:

Give students the choice of one of the following:

1) Draw a cartoon that demonstrates your understanding of what happens to particles

during dissolving.

2) Create and act out a brief skit or interpretive dance that demonstrates your

understanding of what happens to particles during dissolving.

This site shows a representation of salt dissolving: http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/thermochem/solutionSalt.html This links to a clip of salt dissolving: http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf

Assessment:

Journal entries should not receive a score or mark. A positive comment followed by a

question to refocus attention or suggest the next step in learning is very effective.

When reading the journal entries, note which students are getting the idea of the

differences between pure substances and mixtures and heterogeneous and

homogeneous mixtures.

https://exchange.gnb.ca/exchweb/bin/redir.asp?URL=http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/thermochem/solutionSalt.html

https://exchange.gnb.ca/exchweb/bin/redir.asp?URL=http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/thermochem/solutionSalt.html

https://exchange.gnb.ca/exchweb/bin/redir.asp?URL=http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf

18



Possible Next Steps:

Take an in-depth look at the differences between soluble and insoluble in terms of

attraction between particles, and examples of solutes and solvents.

Introduce and use vocabulary and possibly reinforce with simple diagrams:

solution, solute, dissolving, solvent, soluble, insoluble

Have the students dissolve sugar in water.

Questions (Have the students work in small groups to discuss these questions):

What happens in terms of particles?

Imagine the particles. Where are the particles?

What are the particles doing?

What are the particles looking like?

Have students diagram dissolving, labelling solute, solvent, insoluble

This video clip made by NB grade 7 students may be helpful

https://studycasts.wikispaces.com/Solute+and+Solvent+-+Dissolving

And

https://studycasts.wikispaces.com/Soluble+and+Insoluble

https://studycasts.wikispaces.com/Solute+and+Solvent+-+Dissolving

https://studycasts.wikispaces.com/Soluble+and+Insoluble

19



At first, discussions are apt to seem somewhat

artificial. Initially, a bulletin board featuring

carton talk bubbles with suggested sentence

starters may be helpful.

I respectfully disagree . . .

I had a different result . . .

Could you show how you got that

information?

When I was doing ___, I found that . . .

Even though you said ___, I think . . .

The data I have recorded in my

notebook is different from what you

shared. I found . . .

Supporting Class Discussion

No one person is as smart as all of us together.

Page Keeley, in the book “Science Formative Assessment” (2008), uses the analogy of

ping-pong and volleyball to describe discussion interaction. Ping-pong represents the

back and forth question-answer pattern: the teacher asks a question, a student answers,

the teacher asks another question, a student answers, and so on. Volleyball represents

a different discussion pattern: the teacher asks a question, a student answers, and

other students respond in succession; each building upon the previous student’s

response. Discussion continues until the teacher “serves” another question.

A “volleyball” discussion encourages deeper student engagement with scientific ideas.

Students state and give reasons for their ideas. Through the interaction, ideas may be

challenged and clarified. Extensions and applications of ideas may arise as well.

Discussions should avoid the personal and always revolve around ideas,

explanations and reasons. The goal is for students to achieve better understanding.

Share the ping-pong and volleyball analogies with your students. Good discussion takes

practice. You and your students will improve. Many teachers find discussion works best

if all students can see each other, such as in a circle, at least until they become

accustomed to listening and responding to each other.

As the teacher, you will need to:

o establish and maintain a respectful and supportive environment;

o provide clear expectations;

o keep the talk focused on the science;

o carefully orchestrate talk to provide for equitable participation.

It is important to establish discussion

norms with your class. Your expectations

may include:

o Everyone has a right to participate and

be heard.

o Everyone has an obligation to listen

and try to understand.

o Everyone is obliged to ask questions

when they do not understand.

o The speaker has an obligation to

attempt to be clear.

20



It is helpful if teacher questions refer to a big idea rather than specifics. (Could

humans and chickens move their bones without muscles?) Questions should be

phrased so that anyone can enter into the conversation. Opinion questions are

especially good for this (What do you think . . . ?

How do you think . . . ? What if . . . ? Why . . . ?).

Provide plenty of wait time for students. Students give more detailed and complex

answers when given sufficient wait time. Allow wait time after student responses. When

students are engaged and thinking, they need time to process other responses before

contributing. If the discussion is not progressing, have students engage in partner talk.

Partner talk enables the teacher the opportunity to insert “overheard” ideas.

Helpful teacher prompts:

1. What outcome do you predict?

2. Say more about that.

3. What do you mean by . . . ?

4. How do you know?

5. Can you repeat what ____ said in another way?

6. Does anyone agree or disagree with . . . ?

7. Does anyone want to add to or build on to . . . ?

8. Who understands ___’s idea and can explain it in their own words?

9. Let me see if I have got your idea right. Are you saying . . . ?

10. So you are saying that . . .

11. What evidence helped you to think that?

12. Okay, we do not agree. How does each position fit the evidence? What else could

we find out?

References:

Keeley, Page (2008). Science Formative Assessment. Thousand Oaks, CA: Corwin

Press and Arlington, VA: NSTA Press

Michaels, Sarah, Shouse,Andrew W., and Schweingruber, Heidi A. (2008). Ready, Set,

SCIENCE! Washington, DC: The National Academies Press

21



Materials List Different tools for separating each mixture such as:

tweezers, plastic cups, forks, magnets, filter paper, bowls, colanders, and

spoons.

Different types of mixtures of two or three items – some of:

rice and beans

marbles and tennis balls

Cheerios® and Rice Krispies®

styrofoam peanuts and water

metal nuts/washers and rubber bands

iron filings and water

cooking oil and water

salt and water

salt and pepper

sand and water

different colour or size beads

different colour bread ties

salt and sugar

vinegar and water

At least 3 of:

orange juice with pulp; chicken noodle soup; homogenized milk; salsa;

relish; jam; soda water; chocolate chip cookie.

At least 3 of:

shampoo; toothpaste; mustard; Kool-Aid; ketchup; dish detergent.

Glass or clear plastic containers

Magnifying glasses

Microscopes or dissecting scopes

Droppers

Slides and cover slips if available

Flashlight

22



Student Version of Outcomes

109-7 Tell different ways that questions are answered,

problems are solved or decisions are made

112-7 Tell how science and technology affects your life and community

209-3 Use instruments accurately for collecting data.

209-6 Use instruments and materials safely

210-16 Write new questions about mixtures that could

be investigated scientifically.

307-1 Use the particle model of matter to explain the difference between pure substances and mixtures.

307-2 Identify and separate the components of

mixtures

307-3 Describe the characteristics of solutions, using

the particle model of matter

23



Separating Mixtures Examine each mixture and describe the properties (such as shape,

colour, odour, hardness) of each material that makes up the mixture

in the table.

Choose one of your mixtures that has 2 or 3 visible materials. On a

separate piece of paper, draw the mixture and label the parts.

Using the available materials, devise and carry out a way to separate

each mixture. Start with the mixture you drew a picture of. Once the

mixture has been separated, draw a picture of the components.

Mixture Properties of the mixture Method of Separation

24



Heterogeneous or Homogeneous

Activities

Materials:

Mixtures provided by your teacher

Magnifying lens

Microscope

Slides and cover slips

Dropper

Flashlight

Table or foldable to record observations

Procedure:

For each sample:

1) Make observations without any optical aid and sort the containers into 2 groups –

heterogeneous and homogeneous. Record the results on your table or foldable.

2) Make observations using a magnifier. Are there any samples that should be

reclassified? Group the mixtures and record your results.

3) If available, decide if there are some samples in the homogeneous group that should

be examined more closely. Take a drop of the mixture, drop it on a slide. Use another

slide or a cover slip and examine under the microscope. Repeat this step 3 times, taking

samples from different parts of the container. Are there any samples that should be

reclassified? Group the mixtures and record the results.

4) Shine a flashlight through each mixture. Can you see the beam of light in the

mixture? If you can, it means there are little bits floating in the mixture, causing the light

to scatter inside the solution. The mixture is likely heterogeneous.

Remember: Reclassifying an item when seen under higher magnification doesn’t mean

you were wrong the first time. As technology improves and we are able to see smaller

and smaller things, scientists’ understanding changes and models and theories change

too.

25



Observation Chart Sheet Outcomes:

name name name name name

name

name name name name





26



Checklist Sheet

Outcomes Correlations with

Cycles

Yes No

STSE

109-7 Identify different

approaches taken to answer

questions, solve problems, and

make decisions

1st cycle: Journal entry on pre-activity

discussion; mark/record observations

during Separating Mixtures activity and

class discussion; foldable; journal entry;

Think Like a Scientist response

112-7 Provide examples of how

science and technology affect

their lives and their community

1st cycle: Mark/record observations

during pre-activity discussion; Think Like

a Scientist response

SKILLS

209-3 use instruments effectively and accurately for collecting data

2nd

cycle: Mark/record observations

during pre-activity and activity; foldable

209-6 Use tools and apparatus safely


during Separating Mixtures activity

2nd


during activity

210-16 Identify new questions and problems about mixtures that arise from what is learned


during class discussion; Think Like a

Scientist activity

KNOWLEDGE

307-1 Distinguish between pure substances and mixtures, using the particle model of matter

2nd


during pre-activity, activity and class

discussion; foldable

3rd


during the activity and class discussion;

student diagrams; journal entry

307-2 Identify and separate the

components of mixtures


during Separating Mixtures activity and

class discussion; foldable; Think Like a

Scientist response

2nd


during pre-activity, activity and class

discussion; foldable

307-3 Describe the characteristics of solutions, using the particle model of matter

3rd


during the activity and class discussion;

student diagrams; journal entry

27



Observation Checklist

names

109-7

Identify

diffe

rent

appro

aches

taken to a

nsw

er

questio

ns, solv

e

pro

ble

ms, and m

ake d

ecis

ions

112-7

Pro

vid

e e

xam

ple

s o

f how

scie

nce a

nd t

echnolo

gy a

ffect th

eir

lives a

nd their c

om

mu

nity

209-3

use instr

um

ents

effectively

and

accura

tely

for

colle

ctin

g d

ata

209-6

Use t

ools

and a

ppara

tus s

afe

ly

210-1

6 I

dentify

new

questio

ns a

nd

pro

ble

ms a

bout m

ixtu

res that arise

from

what is

le

arn

ed

307-2

Identify

and s

epara

te t

he

com

ponents

of m

ixtu

res

307-1

Dis

tin

guis

h b

etw

een p

ure

substa

nces a

nd m

ixtu

res,

usin

g t

he

part

icle

mo

del of m

atter

307-3

Describ

e the c

hara

cte

ristics o

f

solu

tio

ns, usin

g t

he p

art

icle

mo

del of

ma

tter

28



Student Record Outcome goal Evidence

I can tell different ways that questions are

answered, problems are solved or decisions are

made.

I can tell how science and technology affects my

life and community.

I can use instruments accurately for collecting data.

I can use instruments and materials safely.

I can write new questions about mixtures that could be investigated scientifically.

I can use the particle model of matter to compare pure substances and mixtures.

I can identify and separate the components of mixtures.

I can describe the characteristics of solutions, using the particle model of matter.

Documents

Mixtures and Solutions: Particle Theory of Matter - …and+Solutions... · Mixtures and Solutions: Particle Theory of Matter Science ... Grade 7 Mixtures and Solutions: Particle Theory