9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Syllabus
Content
Key Concepts
Lesson 1
Indicators
Indicators identified
by observation
colour changes in
flowers on soil
composition
Timeline: Acids &
bases
Key
Outcomes
Integrated teaching , learning and assessment
Link to 8
ways
Story Telling: Bush Tucker
H1
Classify common
substances as acidic,
basic or neutral.
Australia’s Aboriginal peoples have always been very perceptive about bush foods and tucker.
With the help of sensory organs for taste, vision and touch they have selectively picked seeds,
fruits and berries to meet their dietary requirements. Fruits contain sugars, organic acids, and
flavonoids that are highly nutritious. We have come a long way in selecting and testing acids,
sugars and other compounds in fruits and vegetable.
https://bushtuckerchem.wordpress.com/
http://www.news.com.au/lifestyle/food/indigenous-plants-fruits-and-vegetables-could-be-keyto-human-nutrition-in-the-future/story-fneuz8wn-1227033953259
Acidic environment using concept map:
Briefly explain the learning structure of the whole topic using the concept map
Identify data and
choose resources to
gather information
about the colour
changes of a range
of indicators.
Tests for acids &
bases.
Indicators to test
acid/bases.
Natural and
synthetic indicators
H2
Testing of acids and bases:
A large fruit bowl of native fruits and berries is placed on the table. Students are asked to use
their sense of smell, taste, sight and touch to identify acids sugars and aromatic compounds.
An antacid tablet is dropped in a glass filled with lemon and students after a brief discussion
explain their observations.
Hand-out: Using the table, students differentiate some common household acids, bases and
neutral substances. The results are added to the table and brought in the next day.
Indicators (pH):
Students learn that substances change colours in the presence of acids and bases (natural and
artificial).
Students Identify few natural indicators such as red cabbage, beets, turmeric, hydrangeas and
blue berries.
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 1
9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Syllabus
Content
Key Concepts
Key
Outcomes
Lesson 2
Perform a first-hand
investigation to
prepare and test a
natural indicator.
Integrated teaching , learning and assessment
Link to 8
ways
Red cabbage experiment
Extraction and
characterization of a
natural indicator.
H11
Conduct the “Red Cabbage Cocktail” experiment
https://bushtuckerchem.wordpress.com/natural-indicators/
http://www.abc.net.au/science/surfingscientist/pdf/lesson_plan16.pdf
Display a red cabbage and ask students to brain storm ways to extract a natural colour
indicator?
Discuss on an optimal approach to extract anthocyanin from red cabbage.
Students demonstrate how to extract the natural, acid-base indicator from cabbage.
Students compare household acids and bases using cabbage extract colour chart with other pH
Indicators. They learn that pH below 7 is acidic and above 7 is basic.
Students collect information on anthocyanin as the active ingredient of red cabbage. They learn
that there are over 300 different types of anthocyanin’s present in many other flowers and
fruits. Students learn that anthocyanin’s in fruits and berries are strong antioxidants and very
beneficial to human health.
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 2
9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Syllabus
Content
Key Concepts
Lesson 3
Indicators
Identify that
indicators such as
litmus,
phenolphthalein,
methyl orange
and bromothymol
blue can be used
to determine the
acidic or basic
nature of a
material over a
range, and that
range is identified
by change in
indicator colour.
Using a range of
various indicators,
test for acids &
bases and compare
colour change to pH
scale.
Integrated teaching , learning and assessment
Key
Outcomes
H2
Link to 8
ways
Relationship between pH and change in colour
List different types of indicators using PowerPoint and show the relationship between pH
/acid/base and colour change.
https://bushtuckerchem.wordpress.com/natural-indicators/
pH indicator simulation
Students complete online simulation activity using the simulation program from “Interactive Lab
Primer”.
Students work in groups and each group is allowed to complete at least one activity.
Compare pH to
colour
Change
http://chem-ilp.net/labTechniques/AcidBaseIdicatorSimulation.htm
Scientific review
Students research and then list using a graphic organiser the advantages and disadvantages of
various indicators and compare their properties to red cabbage indicator. They research on the
applications of pH indicators in science and industry.
H3
Distinct
characteristics of
various indicators
for applications in
science and
industry.
Example graphic organiser table:
Indicator
Acid or base
Advantages
Disadvantages
reaction
litmus
phenolphthalein
methyl orange
bromothymol blue
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 3
9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Syllabus
Content
Key Concepts
Key
Outcomes
Integrated teaching , learning and assessment
Link to 8
ways
Lesson 4
Solve problems by
applying
information about
the colour
changes of
indicators to
classify some
household
substances as
acidic, neutral or
basic.
Compare pH and
colour change of
household
chemicals/natural
products using
various indicators.
H2
Review pH/indicator colour
Students learn the relationship between pH, colour change of various indicators and properties of
household chemicals.
H11
Experiment: pH/indicator colour/compound
Students conduct an experiment to investigate pH of household chemicals and natural compounds
by observing pH and colour change of various indicators.
Students in groups collect 48-well microplates and find the pH of unknown solution by comparing
colour chart and predicting unknown acid or base.
https://bushtuckerchem.wordpress.com/natural-indicators/
Students gain skills to demonstrate how to use indicators to classify household substances (acids
and bases) and natural compounds with the help of pH and indicators.
Indicator
Laundry powder alkylbenzenesulfonates
• sodium bicarbonate NaHCO3
• lemon juice or citric acid C6H8O7
• vinegar or acetic acid CH3COOH
• antacid tablets bicarbonate of Mg, Al, Ca, K,
and Na, alkaline ions
• soda water or carbonic acid
Acid or base reaction
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 4
9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Syllabus
Content
Key Concepts
Integrated teaching , learning and assessment
Key
Outcomes
Link to 8 ways
Lesson 5
Identify and describe
some everyday uses of
indicators including the
testing of soil
acidity/basicity.
Indicators
Testing pH in
soil, food and
industry.
Story telling:
H4
Students learn the importance of testing soil, water and air to control man made environmental
pollution. They understand the significance of using indicator kits to determine acidity in water
and soil. Students learn how tests are conducted that helps in reducing pollution.
Soil testing experiment
H11
Students collect soil samples from their school ground and test the pH of soil using colour code
chart or pH meter.
https://bushtuckerchem.wordpress.com/natural-indicators/
Students learn the importance of maintaining an optimal soil pH Soil that enhances healthy
growth of plants and vital for agriculture. Also, they learn that any change in pH can alter fruit
bearing ability and result in the loss of production.
H3
Students gain knowledge on the importance of pH to the environment and how testing is
carried out in other areas such as in swimming pools, research labs in the University, chemical
industry, pharmaceutical companies, food industry and health sectors.
http://www.abc.net.au/gardening/stories/s3171693.htm
http://www.webmd.com/heartburn-gerd/guide/esophageal-ph-test
https://www.contractlaboratory.com/labclass/industries
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 5
9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Syllabus
Content
Key Concepts
Integrated teaching , learning and assessment
Key
Outcomes
Link to 8 ways
Lesson 6
Identify other natural
indicators in your daily
life (flowers, tea, spices
and drinks)
Linking science
to natural
environment.
Look around you
H2
Students are encouraged to engage in a group activity to search for other natural indicators
around them. They learn about a wide range of natural pH indicators. Students are able to
explain the relationship between pH, colour change and the electronic structure of the
molecule.
Some examples: Blueberries, beets, curcumin, coffee etc
* Curcumin is the active ingredient of turmeric.
http://chemistry.about.com/cs/acidsandbases/a/aa060703a.htm
Assessments
Formative and Summative assessment
Assess student’s knowledge and understanding on “indicators” from lesson 1 to lesson 6.
Students are able to distinguish the properties of different indicators. Students are able to
explain how indicators work and the influence of pH to the environment. Students develop
problem solving skills in extracting and characterising a natural pH indicator. Students are able
to test and identify pH of household chemicals. Students are able to explain the advantages and
disadvantages of various indicators.
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 6
9.3 The Acidic Environment 1. Indicators were identified with the observation that the colour of some flowers depends on soil composition.
Additional Teaching materials can be located at https://bushtuckerchem.wordpress.com/natural-indicators/
Additional research and references:
Merne Altyerre-ipenhe (Food from the Creation time) Reference Group, Douglas J and Walsh F. 2011. Aboriginal people, bush foods knowledge and products
from central Australia: Ethical guidelines for commercial bush food research, industry and enterprises. DKCRC Report 71. Ninti One Limited, Alice Springs.
http://www.nintione.com.au/resource/NintiOneResearchReport_71_BushFoodGuidelines.pdf
Indigenous Gardens Resources
http://www.artssmart.sa.edu.au/files/links/indigenous_gardens_resourc.pdf
Indigenous Food Garden & Native Riverina Birds
http://www.csu.edu.au/__data/assets/pdf_file/0003/752358/2012-Elisa-Bartholomaeus-Final-Report-SoE-Garden-130503.pdf
Nutrition in Aboriginal and Torres Strait Islander Peoples
http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n26.pdf
©2015 Fabian Rozario and Shirley Gilbert UWS PE3 Projects. 7