7th Grade Science Unit: ABC: Acid Base · PDF file7th Grade Science Unit: ABC: Acid Base Chemistry ... and also test water ... will not be assessed at grade 7

Columbus City Schools

Curriculum Leadership and Development Science Department June 2013

1

7th Grade Science Unit:

ABC: Acid Base Chemistry Unit Snapshot

Topic: Conservation of Mass and Energy

Grade Level: 7 Duration: 9 days

Summary: The following activities engage students in exploring the acidity or

alkalinity of substances (pH), through investigations involving pH

testing and analysis. Students will then use their knowledge of pH

values to analyze components of the natural world.

CLEAR LEARNING TARGETS

“I can”…statements

____ use the pH scale to compare and evaluate the acidity or alkalinity of a

compound

____measure pH values in the natural world (e.g. soil, water).

Activity Highlights and Suggested Timeframe

Day 1 Engagement: The objective of this activity is to engage students and formatively

assess their knowledge related to properties of acids and bases through a

discrepant event acid/base demonstration called the Witch’s Potion.

Day 2 Exploration: The objective of the following activity is to give students the

opportunity to work with and begin to develop a basic understanding of the

acidity or alkalinity of a substance through on-line simulation GIZMO: pH Analysis.

Days 3-4 Explanation: The objective of the following activity is to give students the

opportunity to develop their knowledge of pH scale values through close reading

and the CPO Lab Investigation 16B: Acids, Bases, and pH.

Days 5-7 Elaboration: The objective of the following activities is to give students the

opportunity to gain deeper understanding of pH values through close reading and

pH investigations involving substances in our natural world (e.g. water, soil).

Day 8 and on-

going

Evaluation: Formative and summative assessments are used to focus on and

assess student knowledge and growth to gain evidence of student learning or

progress throughout the unit, and to become aware of students misconceptions

related to thermal energy transfer. A teacher-created short cycle assessment will

be administered at the end of the unit to assess all clear learning targets (Day 8).

Day 9 Extension/Intervention: Based on the results of the short-cycle assessment, facilitate

extension and/or intervention activities.



2

LESSON PLANS

NEW LEARNING STANDARDS: 7.PS.1 The properties of matter are determined by the arrangement of atoms.

Substances are classified according to their properties, such as metals and acids.

SCIENTIFIC INQUIRY and APPLICATION PRACTICES: During the years of grades K-12, all students must use the following scientific inquiry and application practices with appropriate laboratory

safety techniques to construct their knowledge and understanding in all science content areas:

Asking questions (for science) and defining problems (for engineering) that guide scientific

investigations

Developing descriptions, models, explanations and predictions.

Planning and carrying out investigations

Constructing explanations (for science) and designing solutions (for engineering)that conclude

scientific investigations

Using appropriate mathematics, tools, and techniques to gather data/information, and analyze and

interpret data

Engaging in argument from evidence

Obtaining, evaluating, and communicating scientific procedures and explanations

*These practices are a combination of ODE Science Inquiry and Application and Frame-work for K-12 Science

Education Scientific and Engineering Practices

COMMON CORE STATE STANDARDS for LITERACY in SCIENCE: *For more information: http://www.corestandards.org/assets/CCSSI_ELA%20Standards.pdf

CCSS.ELA-Literacy.RST.6-8.1 Cite specific textual evidence to support analysis of science and technical texts.

CCSS.ELA-Literacy.RST.6-8.2 Determine the central ideas or conclusions of a text; provide an accurate

summary of the text distinct from prior knowledge or opinions.

CCSS.ELA-Literacy.RST.6-8.3 Follow precisely a multistep procedure when carrying out experiments, taking

measurements, or performing technical tasks.

CCSS.ELA-Literacy.RST.6-8.4 Determine the meaning of symbols, key terms, and other domain-specific words

and phrases as they are used in a specific scientific or technical context relevant to grades 6–8 texts and

topics.

CCSS.ELA-Literacy.RST.6-8.9 Compare and contrast the information gained from experiments, simulations,

video, or multimedia sources with that gained from reading a text on the same topic.

STUDENT KNOWLEDGE: Prior Concepts Related to Properties of Matter

PreK-2: Properties can be used to sort objects. Changes, including phase changes are explored.

Grades 3-5: Objects are composed of matter which has mass* and volume. Properties of solids, liquids and

gases are explored. Phase changes are reversible and do not change the identity of the material. The total

amount of matter and mass* remains the same when something changes.

Grade 6: All matter is made up of atoms that are in constant random motion. Elements, compounds and

molecules are introduced. The properties of solids, liquids and gases, and changes of phase are explained

by the motion and spacing of the particles.

Future Application of Concepts

High School: Metalloids and pH calculations are introduced. Mixtures are classified as homogenous or

heterogeneous. Trends in the properties and atomic structure of elements are related to the periodic table.

The role of valence electrons in reactivity is explored, balanced chemical equations are written and

stoichiometric problems are solved.

http://www.corestandards.org/assets/CCSSI_ELA%20Standards.pdf



3

MATERIALS: Engage

5 500mL beakers or glasses

Vinegar and Ammonia

Phenolphthalein Indicator – provided by CCS

Science Department

Water

pH Analysis GIZMO Student Exploration Sheet

Page 1

Blue and Red Litmus Paper

Lemon Juice and Soap

Explore

Computers/Internet

GIZMO lesson materials and Student

Exploration Sheet

Explain

CPO Lab Investigation 16B Lab Materials

Elaborate

pH: A Balancing Act Student WS

Soil and Water samples

pH testing paper

pH in Our Natural World: Water and Soil

Student WS

VOCABULARY: Primary

Acidic

Acidity

Alkalinity

Basic

Neutral

pH

pH Scale

Secondary

Indicator

Litmus Paper

Phenolphthalein

SAFETY During testing and investigation of chemicals/substances, students should

wear safety glasses/goggles, and take other lab safety precautions.

ADVANCED

PREPARATION

If possible, reserve computers lab/laptops for www.explorelearning.com

GIZMO: pH Analysis.

Gather and prepare materials for witch’s potion demo and CPO

Investigation lab 16B.

ENGAGE (1 day)

(What will draw students into the

learning? How will you determine

what your students already know

about the topic? What can be

done at this point to identify and

address misconceptions? Where

can connections are made to

the real world?)

Objective: The objective of this activity is to engage students and formatively

assess their knowledge related to properties of acids and bases

through a discrepant event demonstration.

What is the teacher doing?

THE WITCH’S POTION DEMO (Day 1)

PREPARATION: See Teacher

Information Sheet. The teacher

should set-up the

demonstration without

students seeing what is being

done. NOTE: Do not prepare

too far in advance, as the

liquids may evaporate causing

the demonstration to not work

properly. (5 minute maximum)

It is suggested that you

practice this demo before

showing to students.

The teacher chooses 4

volunteers to read the poem

and assist in the demo.

Ask students to hypothesize

what may have occurred to

cause the color changes.

What are the students doing?

THE WITCH’S POTION DEMO (Day 1)

1. 4 students are involved in assisting

during the teacher demonstration.

2. All students observe the

demonstration and hypothesize

what may have occurred to cause

the color changes.

http://www.explorelearning.com/



4

Project the

www.explorelearning.com

GIZMO: pH Analysis on a

screen or SMARTboard.

If you are unfamiliar with

GIZMO’s or do not know your

username/password, see your

Math CCIT or call the CCS

science office @ x5297.

Distribute Page 1 of the pH

Analysis GIZMO Student

Exploration Sheet. Additional

lesson materials are available

on the


website.

Facilitate as students answer

and discuss prior knowledge

questions.

Small group activity or teacher

demonstration - Use blue and

red litmus paper to

demonstrate the use of an

indicator to determine if a

substance is an acid or base

by testing lemon juice and

soap.

-Lemon Juice is an acid and

will turn blue litmus to red.

-Soap is a base and will turn

red litmus to blue.

Facilitate the GIZMO Warm-up

as a class, and also test water

and vinegar.

Relate the pH of ammonia,

water and vinegar to the

witch’s potion demo.

Optional: Use litmus paper to

show that ammonia is a base,

and vinegar is an acid and

water is neutral.

3. Students complete prior knowledge

questions on the WS.

4. Students test lemon juice and soap

using litmus paper to determine if

the substance is an acid or base.

-This can also be a teacher

demonstration.

5. As a class, students work together

to learn how to use the GIZMO

through the GIZMO Warm-up.

-In addition to ammonia, also test

water and vinegar.

6. Relate the results of the tests to the

Witch’s Potion Demo.

7. Optional: Use litmus paper to show

that ammonia is a base, and

vinegar is an acid and water is

neutral.

8. Exit Ticket suggestion: Explain how

the witch’s potion worked, and

how it relates to acids, bases, and

indicators.





5

EXPLORE (1 day)

(How will the concept be

developed? How is this relevant

to students’ lives? What can be


address misconceptions?)

Objective: The objective of the following activity is to give students the

opportunity to work with and begin to develop a basic understanding

of the acidity or alkalinity of a substance through on-line simulation

GIZMO: pH Analysis


GIZMO: pH Analysis

www.explorelearning.com (Day 2)

Activity A & B can be

completed as a whole group

class instruction with teacher

facilitation or if possible,

students working individually or

partners on computers, laptops,

or IPads.

Additional lesson materials are

available on the


website.

If you are unfamiliar with

GIZMO’s or do not know your

username/password, see your

Math CCIT or call the CCS

science office @ x5297.

Follow-up with a class discussion


GIZMO: pH Analysis

www.explorelearning.com (Day 2)

1. Students work individually, with a

partner, or as a class to test various

substances to determine their pH

value.

-Complete Activity A & B

EXPLAIN (2 days)

(What products could the

students develop and share?

How will students share what they

have learned? What can be


address misconceptions?)

Objective: The objective of the following activity is to give students the

opportunity to develop their knowledge of pH scale values through

the CPO Lab Investigation: Acids, Bases, and pH.


CPO LAB INVESTIGATION 16B (Days 3-4)

Using the CPO textbook pp.

394-395, have students

compare the properties of

acids and bases.

Facilitate a close reading of

CPO textbook p. 397

NOTE: The discussion of hydroxide

and hydrogen ions as they relate to the

pH scale is reserved for high school and

will not be assessed at grade 7.

Facilitate CPO Lab Investigation

16.B.


CPO LAB INVESTIGATION 16B (Days 3-4)

1. Using the CPO textbook pp. 394-395,

compare the properties of acids and

bases.

2. Engage in a close reading of CPO

textbook p. 397.

3. Complete Lab Investigation 16B.






6

ELABORATE (3 days)

(How will the new knowledge be

reinforced, transferred to new

and unique situations, or

integrated with related

concepts?)

Objective: The objective of the following activities is to give students the

opportunity to gain deeper understanding of pH values through pH

investigations involving substances in our natural world.


pH in our Natural World(Day 5)

Facilitate a close reading of

CPO textbook pp. 398-399

and/or Show the

www.unitedstreaming.com

video clip: The pH in the

Chemistry of Nature [3:19]

Distribute the WS – pH: A

Balancing Act.

Split students into 4 groups and

facilitate a close reading on

pp. 402-403 in the CPO

textbook.

Facilitate the sharing of

answers.

Administer a quick write in

student journals or on a

separate piece of paper:

“Summarize how pH plays an

important role in your body.”


pH in our Natural World (Day 5)

1. Students engage in close reading of

CPO textbook pp. 398-399 and/or

watch the www.unitedstreaming.com

video clip: The pH in the Chemistry of

Nature [3:19]

2. Using the CPO Textbook pp. 402-403,

students either read the sections

aloud or silently.

3. Each group of students is assigned a

set of questions to answer using their

reading section and then present

their findings to the class.

4. All students are responsible for

summarizing the answer to each

question on their WS.

5. Students perform a quick write

summarizing how pH plays an

important role in the body either in

journals, or on the back of their

paper.


pH in our Natural World: WATER (Day 6)

PREPARATION: Teacher collects

water samples from various

parts of the school (i.e. water

fountain, bathroom sink, fish

tanks, bottled water, etc.) or

asks students to gather the

water samples.

It is recommended that

students develop their own

investigation for testing the pH

of the water samples. However,

a lab sheet template has been

provided for those students that

need a more guided

experience: pH in Our Natural

World: WATER WS.

Teacher facilitates pH testing

and investigation.

OPTIONAL Extension: Test the

effects of water pH on an

Elodea plant (aquatic plant).


pH in our Natural World: WATER (Day 6)

1. Students gather water samples

from either home or different

parts of the school

yard/building

2. Students develop and

investigate the pH of the water

samples and complete lab

sheet.

http://www.unitedstreaming.com/




7


pH in our Natural World: SOIL (Day7)

PREPARATION: Teacher collects

soil samples from various

sources, asks students to bring in

soil samples, or students gather

soil samples from around the

schoolyard. Include a fertilized

potting soil sample, as fertilizer is

a strong base.

Teacher facilitates the

gathering of soil samples and

students pH testing. NOTE: Use

distilled water to create soil

solutions.

It is recommended that

students develop their own

investigation for testing the pH

of the soils. However, a lab

sheet template has been

provided for those students that

need a more guided

experience: pH in Our Natural

World: SOIL WS

NOTE: Students will be

completing a similar lab using

outside water sources during

the Earth Science Unit.

OPTIONAL Extension: Test the

effects of soil pH on plant

growth.


pH in our Natural World: SOIL (Day 7)

1. Students gather soil samples

from either home or different

parts of the school yard.

2. Students develop an

investigation to test and

compare the pH of the soil

samples and complete a lab

report.

EVALUATE (on-going)

(What opportunities will students

have to express their thinking?

When will students reflect on

what they have learned? How

will you measure learning as it

occurs? What evidence of

student learning will you be

looking for and/or collecting?)

Objective: The objective of the assessments is to focus on and assess student

knowledge and growth to gain evidence of student learning or

progress throughout the lesson, and to become aware of students

misconceptions related to the alkalinity/acidity of substances and the

pH Scale.

Formative

How will you measure learning as it occurs?

Consider developing a

teacher-created formative

assessment.

1. Student’s hypotheses based on the

Witch’s Potion Demo as well as prior-

knowledge/warm-up GIZMO

questions can be used to formatively

assess students’ prior knowledge of

acids and bases.

2. GIZMO and Lab 16B

questions/answers – These can be

used to assess the student’s ongoing

understanding of the pH scale.

Summative

What evidence of learning will demonstrate to

you that a student has met the learning

objectives?

1. pH in our Natural World Investigations

can be used to assess the students

ability to test and relate pH values to

various aspects of the natural world.

2. Teacher-created short cycle

assessment will assess all clear

learning targets (Day 8).



8

EXTENSION/

INTERVENTION (1 day or as needed)

EXTENSION

1. Test acids/bases of various strengths

to determine rates of corrosion on

metal pennies.

2. CPO Chapter Activity: Acid Rain and

Stone Structures on CPO textbook p.

404.

3.GEO STAC: Acid Precipitation Lesson:

http://gis.lanecc.edu/geostac/tyser_f/

acid-precipitation

4. pH and plant growth/survival

investigation:

http://www.ncsu.edu/sciencejunction/

depot/experiments/water/lessons/pH/

pHlesson2.htm

INTERVENTION

1. www.unitedstreaming.com related

videos

2. BBC KS3 Bitesize Interactive: Acids,

bases, and metals -

http://www.bbc.co.uk/bitesize/ks3/scie

nce/chemical_material_behaviour/aci

ds_bases_metals/activity/

2. GEMS Alien Juice Bar -

http://scienceview.berkeley.edu/show

case/flash/juicebar.html

3. The pH Factor -

http://www.miamisci.org/ph/

COMMON

MISCONCEPTIONS

All acids are corrosive.

-Students can use litmus paper to test common foods to discover that

many of the things they eat are acids.

A base (alkalinity) is the opposite of an acid (acidity) and therefore not

harmful or corrosive.

-Bases have various strengths and can also be corrosive.

The acidity/alkalinity strength is based on how much of the substance is

present (e.g. the more substance there is, the stronger the

acidity/alkalinity.)

-pH is based on the chemical make-up of the substance, not the amount

there is.

Strategies to address misconceptions:

Misconceptions can be addressed through the use of Discovery Ed video clips,

and litmus/pH tests of various substances.

DIFFERENTIATION

Lower-level: Consider partnering lower-level students with higher-level students

while working on GIZMO simulation or investigation activities;

Consider assigning specific substances for testing during

investigations; Consider performing a read-aloud during close

reading assignments.

Higher-Level: Consider providing opportunities for higher-level students to test

other substances that they may choose; Consider allowing students

to complete extension activities; Consider having students create

assessment questions for review.

Strategies for meeting the needs of all learners including gifted students, English

Language Learners (ELL) and students with disabilities can be found at the

following sites:

ELL Learners:

http://www.ode.state.oh.us/GD/DocumentManagement/DocumentDownload.

aspx?DocumentID=105521

Gifted Learners:

http://www.ode.state.oh.us/GD/DocumentManagement/DocumentDownload.

aspx?DocumentID=105522

Students with Disabilities:

http://www.education.ohio.gov/GD/DocumentManagement/DocumentDownlo

ad.aspx?DocumentID=105523

http://gis.lanecc.edu/geostac/tyser_f/acid-precipitation

http://gis.lanecc.edu/geostac/tyser_f/acid-precipitation

http://www.ncsu.edu/sciencejunction/depot/experiments/water/lessons/pH/pHlesson2.htm




http://www.bbc.co.uk/bitesize/ks3/science/chemical_material_behaviour/acids_bases_metals/activity/



http://scienceview.berkeley.edu/showcase/flash/juicebar.html

http://scienceview.berkeley.edu/showcase/flash/juicebar.html

http://www.miamisci.org/ph/

http://www.ode.state.oh.us/GD/DocumentManagement/DocumentDownload.aspx?DocumentID=105521




http://www.education.ohio.gov/GD/DocumentManagement/DocumentDownload.aspx?DocumentID=105523

http://www.education.ohio.gov/GD/DocumentManagement/DocumentDownload.aspx?DocumentID=105523



9

ADDITIONAL

RESOURCES

Textbook Resources:

CPO Physical Science Textbook

Chapter 16.2: Acids, Bases, and pH pp. 394-406

CPO Lab Investigation 16B

Websites:

Phet Interactive Simulation: http://phet.colorado.edu/en/simulation/acid-

base-solutions

Acid-base basics: http://www.chem4kids.com/files/react_acidbase.html

Acid-base chemistry: http://www.shodor.org/unchem/basic/ab/

Acids, bases:

http://www.files.chem.vt.edu/RVGS/ACT/notes/Notes_on_acids_and_bas

es.html

The pH scale: http://www.hbci.com/~wenonah/hydro/ph.htm

Natural indicators: http://www.pharmainfo.net/reviews/natural-ph-

indicators-review,

http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/household-

indicators.shtml

Pickle science: http://ezinearticles.com/?Pickles---Science-in-Your-

Kitchen&id=1051549

Discovery Ed (www.unitedstreaming.com):

Elements of Chemistry: Acids, Bases, and Salts [20:00]

Literature:

Brent, Lynette. (2009).Acids and Bases. Crabtree Pub.Co.

Baldwin, Carol. (2006). Acids & Bases. Raintree Publishers.

Oxlade, Chris. (2007). Acids and Bases. Heinemann Library.

http://phet.colorado.edu/en/simulation/acid-base-solutions

http://phet.colorado.edu/en/simulation/acid-base-solutions

http://www.chem4kids.com/files/react_acidbase.html

http://www.shodor.org/unchem/basic/ab/

http://www.files.chem.vt.edu/RVGS/ACT/notes/Notes_on_acids_and_bases.html

http://www.files.chem.vt.edu/RVGS/ACT/notes/Notes_on_acids_and_bases.html

http://www.hbci.com/~wenonah/hydro/ph.htm

http://www.pharmainfo.net/reviews/natural-ph-

http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/household-indicators.shtml

http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/household-indicators.shtml

http://ezinearticles.com/?Pickles---Science-in-Your-Kitchen&id=1051549

http://ezinearticles.com/?Pickles---Science-in-Your-Kitchen&id=1051549




10

ENGAGE - THE WITCHES POTION DEMO Teacher Info…

PREPARATION: Prepare the following without letting students see what you are doing.

However, do not prepare too far in advance, as the liquids may evaporate causing the

experiment to not go as planned.

Materials:

5 beakers (500 mL) or glasses

Container of water

Vinegar (Acid)

Ammonia (Base)

Phenolphthalein Indicator (turns pink in the presence of a base)

Eye droppers

Witch’s Potion Poem Sheet

1. Prepare 4 beakers or glasses and label them:

2. In #1 and #3 put 5 drops of phenolphthalein

3. In #2 and #4 put 5 drops of ammonia

(If you prepare these ahead of time, then be sure to stack them, one inside the other,

with an empty one inside the top one. This prevents your drops from evaporating.)

4. In #5 put 20 drops of vinegar.

5. Fill a large container with water.

6. Choose 4 volunteers to be the 4 witches. These students will read their sections of the

poem and do their section of the experiment.

Teacher Background: What is actually happening?

Phenolphthalein is a chemical indicator that turns pink in the presence of a base.

Therefore when beaker #1 is added to beaker #2 and beaker #3 is added to beaker

#4, the phenolphthalein reacts with the ammonia(base) and turns the solution bright

pink. When the phenolphthalein/ammonia solutions are added to beaker #5, the

ammonia (base) is neutralized by the vinegar (acid) and the solution turns clear again.

5 drops

phenolpthalein 5 drops

ammonia

5 drops


ammonia

20 drops

vinegar

BEAKER #1 BEAKER #2 BEAKER #3 BEAKER #4 BEAKER #5



11

The Witches Potion Poem – Teacher Information:

Teacher/Narrator: “Four witches made quite a commotion. When I invited

them to create a potion. Into four glasses went the magic brew...”

Experiment…Fill beakers #1-4 ¼ full with water.

Teacher/Narrator: "And into a rage the first witch flew: She shrieked,”

Witch #1: “There's no magic in this drink. To cast a

spell, it must be pink!"

Teacher/Narrator: “The second witch laughed,”

Witch #2: "The pink is here. Pour your brew in--the color

will appear!"

Experiment…Witch #1 pour water into the glass of Witch #2.

5 drops


ammonia

5 drops


ammonia

20 drops

vinegar


5 drops


ammonia

20 drops

vinegar

5 drops

phenolpthalein

5 drops

ammonia




12

Teacher/Narrator: "The third witch shrieked,”

Witch #3: “We need more!”

Teacher/Narrator: “And gave her brew to Witch number Four."


Witch #4"Now there are two glasses of pink, But no one

asked me what I think! I'll invoke my powers to make it

clear. Be Gone Pink! Watch it disappear!"

Experiment…Pour both glasses with the pink solution into Beaker #5.

4 Student Witch’s Sheet:

5 drops

phenolpthalein

5 drops

ammonia


20 drops

vinegar

5 drops

phenolpthalein

5 drops

ammonia


20 drops

vinegar

10 drops

phenolpthalein

10 drops

ammonia



13

THE WITCHES POTION

Teacher/Narrator: "Four witches made quite a commotion. When I invited them

to create a potion. Into four glasses went the magic brew..."

Experiment…Fill each beaker ¼ full with water.

Teacher/Narrator: "And into a rage the first witch flew: She shrieked,”

Witch #1: “There's no magic in this drink. To cast a

spell, it must be pink!"

Teacher/Narrator: “The second witch laughed,”

Witch #2: "The pink is here. Pour your brew in--the color

will appear!"


Teacher/Narrator: "The third witch shrieked,”

Witch #3: “We need more!”

Teacher/Narrator: “And gave her brew to Witch number Four."


Witch #4:"Now there are two glasses of pink, But no one

asked me what I think! I'll invoke my powers to

make it clear. Be Gone Pink! Watch it

disappear!"

Experiment…Pour both glasses with the pink solution into the large container.



14

Name: __________________________________Date: _____________________Period____________

Student Exploration: pH Analysis www.explorelearning.com

Vocabulary: acid, acidic, alkaline, base, indicator, neutral, pH

Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Acids are substances that produce hydrogen ions (H+) when dissolved in water. Lemon juice is an

example of an acid.

A. What does lemon juice taste like? ________________________________________ B. What does it feel like if lemon juice gets in your eye? _________________________

2. Bases are substances that produce hydroxide ions (OH-) when dissolved in water. Hand soap is an

example of a base.

A. What does soap feel like? ______________________________________________ B. What does soap taste like? _____________________________________________ C. What does it feel like if soap gets in your eye? ______________________________

Gizmo Warm-up The strength of an acid or base is measured on the pH scale. The term “pH” is short for “potential of hydrogen.” It is a measure of how many excess H+ ions there are in a solution. The pH scale runs from 0 to 14, with 0 representing the highest concentration of hydrogen ions. Acidic substances have a pH below 7, while alkaline substances (bases) have a pH above 7. Pure water has a pH of 7 and is considered neutral. The pH Analysis Gizmo™ allows you to find the pH of a variety of liquids. In the Gizmo, check that the Substance in the tube is Ammonia, and click Test. Wait until the animation is finished. 1. Indicators change color in acids or bases. What is the color of the pH paper? ___________

2. Compare the paper to the pH color chart. What is the pH of ammonia? _____________

3. Is ammonia acidic or alkaline? _____________




15

Name: __________________________________Date: _____________________Period____________

Activity A:

Measuring pH

Get the Gizmo ready:

Click Reset.

Check that the 0-14 paper is selected.

Goal: Find the pH of 18 common substances. 1. Test: Use the Gizmo to find the pH of each of the available substances. Classify each substance as acidic

(pH < 7), alkaline (ph > 7), or neutral (pH = 7).

0-14 pH indicator paper

Material in the tube pH value Acidic, alkaline, or neutral?

Baking soda

Bleach

Coffee

Cola

Drain cleaner

Hand soap

Juice (lemon)

Juice (orange)

Juice (tomato)

Milk

Milk of magnesia

Oven cleaner

Saliva (human)

Shampoo

Stomach acid

Vinegar

Water (distilled)

Water (ocean)

2. Summarize: Compare all the acidic substances and all the alkaline substances.

A. In general, what types of substances tend to be acidic? _______________________

___________________________________________________________________

B. What types of substances tend to be alkaline? ______________________________ ___________________________________________________________________

Name: __________________________________Date: _____________________Period____________



16

Activity B:

More accurate pH


Click Reset.

Select the 4.5-7.5 paper.

Goal: Find the pH of substances in a more accurate way. 1. Test: Before you begin testing with the 4.5-7.5 paper, list the pH values of the substances below that you

found using the 0-14 pH indicator paper. Then find the pH of each substance with the 4.5-7.5 paper.

4.5-7.5 pH indicator paper

Material in the tube pH value (0 to 14 paper) pH value (4.5 to 7.5 paper)

Coffee

Milk

Oven cleaner

Saliva (human)

Shampoo

Stomach acid

Water (distilled)

2. Analyze: Compare the pH values in each column.

A. How do these values compare? _________________________________________

___________________________________________________________________ B. What is an advantage of using the 4.5-7.5 paper? ___________________________

___________________________________________________________________ C. What is a disadvantage of using the 4.5-7.5 paper? __________________________

___________________________________________________________________ D. Given the results from two kinds of indicator paper, which substances appear to be neutral (pH =

7)? _____________________________________________________



17

pH Analysis Answer Key Vocabulary: acid, acidic, alkaline, base, indicator, neutral, pH

Prior Knowledge Questions (Do these BEFORE using the Gizmo.) [Note: The purpose of these questions is to activate prior knowledge and get students thinking. Students are not expected to know the answers to the Prior Knowledge Questions.]

1. Acids are substances that produce hydrogen ions (H+) when dissolved in water. Lemon juice is an

example of an acid.

A. What does lemon juice taste like? Lemon juice has a sour taste. B. What does it feel like if lemon juice gets in your eye? A burning sensation.

2. Bases are substances that produce hydroxide ions (OH-) when dissolved in water. Hand soap is an

example of a base.

A. What does soap feel like? Soap has a slippery texture. B. What does soap taste like? Soap has a bitter taste. C. What does it feel like if soap gets in your eye? A burning sensation.

Gizmo Warm-up The strength of an acid or base is measured on the pH scale. The term “pH” is short for “potential of hydrogen.” It is a measure of how many excess H+ ions there are in a solution. The pH scale runs from 0 to 14, with 0 representing the highest concentration of hydrogen ions. Acidic substances have a pH below 7, while alkaline substances (bases) have a pH above 7. Pure water has a pH of 7 and is considered neutral. The pH Analysis Gizmo™ allows you to find the pH of a variety of liquids. In the Gizmo, check that the Substance in the tube is Ammonia, and click Test. Wait until the animation is finished. 1. Indicators change color in acids or bases. What is the color of the pH paper? Dark green

2. Compare the paper to the pH color chart. What is the pH of ammonia? 11

3. Is ammonia acidic or alkaline? Alkaline



18

Activity A:

Measuring pH


Click Reset.

Check that the 0-14 paper is selected.

Goal: Find the pH of 18 common substances. 1. Test: Use the Gizmo to find the pH of each of the available substances. Classify each substance as acidic

(pH < 7), alkaline (ph > 7), or neutral (pH = 7).

0-14 pH indicator paper

Material in the tube pH value Acidic, alkaline, or neutral?

Baking soda 8 Alkaline

Bleach 11 Alkaline

Coffee 5 Acidic

Cola 2 or 3 Acidic

Drain cleaner 13 Alkaline

Hand soap 9 or 10 Alkaline

Juice (lemon) 2 or 3 Acidic

Juice (orange) 3 Acidic

Juice (tomato) 4 Acidic

Milk 6 or 7 Acidic or neutral

Milk of magnesia 10 Alkaline

Oven cleaner 13 or 14 Alkaline

Saliva (human) 6 or 7 Acidic or neutral

Shampoo 6 or 7 Acidic or neutral

Stomach acid 1 Acidic

Vinegar 4 Acidic

Water (distilled) 6 or 7 Acidic or neutral

Water (ocean) 8 Alkaline

2. Summarize: Compare all the acidic substances and all the alkaline substances.

A. In general, what types of substances tend to be acidic?

Fruit juices and other beverages or food (cola, coffee, vinegar) tend to be acidic.

B. What types of substances tend to be alkaline? Most of the alkaline substances are cleaners. These include hand soap, oven cleaner, bleach, and drain cleaner.



19

Activity B:

More accurate pH


Click Reset.

Select the 4.5-7.5 paper.

Goal: Find the pH of substances in a more accurate way. 1. Test: Before you begin testing with the 4.5-7.5 paper, list the pH values of the substances below that you

found using the 0-14 pH indicator paper. Then find the pH of each substance with the 4.5-7.5 paper.

4.5-7.5 pH indicator paper

Material in the tube pH value (0 to 14 paper) pH value (4.5 to 7.5 paper)

Coffee 5 5

Milk 6 or 7 6.5

Oven cleaner 13 or 14 7.5*

Saliva (human) 6 or 7 6.5

Shampoo 6 or 7 7

Stomach acid 1 4.5*

Water (distilled) 6 or 7 7

*Substances with a pH below 4.5 or above 7.5 cannot be measured accurately with the 4.5-7.5 indicator paper.

2. Analyze: Compare the pH values in each column.

A. How do these values compare?

Most of the values are the same or nearly the same, but some are very different. B. What is an advantage of using the 4.5-7.5 paper?

It gives a more accurate pH value for substances with a pH between 4.5 and 7.5. C. What is a disadvantage of using the 4.5-7.5 paper?

The pH paper does not work for substances whose pH is not between 4.5 and 7.5. D. Given the results from two kinds of indicator paper, which substances appear to be neutral (pH =

7)? Shampoo and distilled water appear to be neutral.



20

Name_________________________________________Date________________Period_______________

pH: A Balancing Act CPO Textbook pp.402-403

Directions: Using the CPO Textbook pp.402-403, read Acids, bases, and YOU as a class. Then,

read your assigned section of pH: A Balancing Act. Answer your assigned questions and

share your findings with the class.

Group 1: Imbalances

What is an acid-base balance?

What two organs regulate this

balance? How do they do this?

Group 2: Acidosis and its causes

What is acidosis?

What are some causes of

acidosis?

Group 3: Alkalosis and its causes

What is alkalosis?


alkalosis?

Group 4: Balancing Act: food, drink,

exercise, calm, acid, base…

Is our body’s pH perfectly

neutral?

In what ways can our diet affect

the pH in our bodies?

http://chemistryhelp.net/files/the-ph-scale.png



21

Name_________________________________________Date________________Period_______________

pH: A Balancing Act CPO Textbook pp.402-403

TEACHER-KEY Directions: Using the CPO Textbook pp.402-403, read Acids, bases, and YOU as a class. Then,

read your assigned section of pH: A Balancing Act. Answer your assigned questions and

share your findings with the class.

Group 1: Imbalances

What is an acid-base balance?

What two organs regulate this

balance? How do they do this?

An acid-base balance is the pH

balance that occurs within the human

body. A balance is required for our

organs and body to function properly.

The two organs that regulate this

balance are:

1) Lungs: dispose of excess CO2

2) Kidneys: remove excess acid in our

blood and dispose of it as urine,

Group 2: Acidosis and its causes

What is acidosis?


acidosis?

Acidosis is a pH imbalance in which the

body has too much acid.

Causes:

1) Lung Disease

2) Smoking

3) Diabetes

4)Severe Diarrhea

5)Heart/Liver Failure

6)Kidney Disease

7) Prolonged Exercise

Group 3: Alkalosis and its causes

What is alkalosis?


alkalosis?

Alkatosis is a pH imbalance in which the

body has too much base in the body’s

fluids.

Causes:

1) Hyperventilation

2) Altitude

3)Any disease that causes the bod to

lose too much CO2.

Group 4: Balancing Act: food, drink,

exercise, calm, acid, base…

Is our body’s pH perfectly

neutral? What is the normal pH of

a healthy person?

In what ways can our diet affect

the pH in our bodies?

No,the body’s pH is slightly alkaline

(7.35-7.45)

Too much meat and not enough

veggies will cause pH to become too

acidic.

http://chemistryhelp.net/files/the-ph-scale.png



22

Name_______________________________________Date________________________Period_____

pH in Our Natural World: WATER Guiding questions:

What is the pH of the water in the school?

Does all water have the same pH?

Hypotheses:

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

Procedures:

1) Gather water samples.

Water Test Site: _____________________________________________________________________

2) Dip pH strips in your water solution and leave submerged for at least 2 seconds.

Place your strips here. Observe color.

Compare your strips to the pH key to approximate the pH of your water sample.

Estimating to the nearest decimal, what is the pH? ______

3) Using graph paper, create a data table and record the results of all pH tests.

Develop a graph using your data to show the comparison between various water

samples and their pH levels.



23

Name_______________________________________Date________________________Period_____

Post-lab questions:

1) Compare and contrast the pH values of the various samples. Summarize the results.

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

2) Were your hypotheses correct?

What is the average pH of the water in the school? ________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Do all soils have the same pH? _______________

3) What factors can affect the pH of water? _________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Extension

Guiding Question:

How does the pH of water affect aquatic plant growth and survival?

Develop an investigation that tests the growth of Elodea (an aquatic plant) in varying

pH levels to determine which water pH level is best growth and survival.



24

Name_______________________________________Date________________________Period_____

pH in Our Natural World: WATER – TEACHER KEY Guiding questions:

What is the pH of the water in the school?

Does all water have the same pH?

Hypotheses:

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

Procedures:

1) Gather water samples.

Water Test Site: _____________________________________________________________________

2) Dip pH strips in your water solution and leave submerged for at least 2 seconds.


Compare your strips to the pH key to approximate the pH of your water sample.



Develop a graph using your data to show the comparison between various water

samples and their pH levels.

Answers Will Vary

Examples: Water Fountain, Bottled Water, Sink Water, Fish tank, etc.

Answers Will Vary

Data will vary depending on samples



25

Name_______________________________________Date________________________Period_____

Post-lab questions:


__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________


What is the average pH of the water in the school? ________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Does all water have the same pH? _______________

3) What factors can affect the pH of water? _________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Extension

Guiding Question:

How does the pH of water affect aquatic plant growth and survival?

Develop an investigation that tests the growth of Elodea (an aquatic plant) in varying

pH levels to determine which water pH level is best growth and survival.

Answers Will Vary

Answers Will Depend on Location

Filtration systems (Treatment plant); pipes, organisms in water, pollution, run-off,

soil composition through which water moves, etc.)

No



26

Name_______________________________________Date________________________Period_____

pH in Our Natural World: SOIL Guiding questions:

What is the pH of the soil around the school?

Do all soils have the same pH?

Hypotheses:

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

Procedures:

1) Gather soil samples.

Soil Test Site: _____________________________________________________________________

2) Create a soil solution by mixing your soil sample with distilled water.

3) Dip pH strips in your soil solution and leave submerged for at least 2 seconds.


Compare your strips to the pH key to approximate the pH of your soil solution.



Develop a graph using your data to show the comparison between various soils and

their pH levels.



27

Name_______________________________________Date________________________Period_____

Post-lab questions:


__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________


What is the average pH of the soil around the school? ______________________________

__________________________________________________________________________________

__________________________________________________________________________________


3) What factors can affect the pH of soil? ____________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Extension

Guiding Questions:

Do you think all plants grow and survive in the same pH level soil?

Develop an investigation that tests the growth of a particular plant in soils with varying

pH levels to determine which soil is best for that particular plant.



28

Name_______________________________________Date________________________Period_____

pH in Our Natural World: SOIL – Teacher Key Guiding questions:

What is the pH of the soil around the school?

Do all soils have the same pH?

Hypotheses:

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

Procedures:

1) Gather soil samples.

Soil Test Site: _____________________________________________________________________

2) Create a soil solution by mixing your soil sample with distilled water.

3) Dip pH strips in your soil solution and leave submerged for at least 2 seconds.


Compare your strips to the pH key to approximate the pH of your soil solution.



Develop a graph using your data to show the comparison between various soils and

their pH levels.

Answers Will Vary

Examples: Soil near trees, Garden, Fertilized potting soil, Flower beds, Soil

under grassy area, Soil near road, etc.

Answers Will Vary

Data is dependent upon soil samples



29

Name_______________________________________Date________________________Period_____

Post-lab questions:


__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________


What is the average pH of the soil around the school? ______________________________

__________________________________________________________________________________

__________________________________________________________________________________


3) What factors can affect the pH of soil? ____________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

Extension

Guiding Questions:

Do you think all plants grow and survive in the same pH level soil?

Develop an investigation that tests the growth of a particular plant in soils with varying

pH levels to determine which soil is best for that particular plant.

Answers Will Vary

Answer Will Depend on Location

Soil Composition, Acid Rain/Pollution in Area, Fertilizer, Animals in the Area,

Vegetation, Soil forming factors, Rainfall and temperature,

No

Documents

7th Grade Science Unit: ABC: Acid Base · PDF file7th Grade Science Unit: ABC: Acid Base Chemistry ... and also test water ... will not be assessed at grade 7