Living with acids and bases
Unit of work contributed by Kerrith McGrath, Sacred Heart College, Vic
Context
The Year 9 course is divided into three themes over the year; Medicine, The World and Technology.
These themes are supported by manuals that are written and revised each 'trimester' by the three
teachers who teach the five classes at our school. Each theme runs for approximately 10-12 weeks.
Medicine begins the year and is divided into three broad sections: Study of microbes, Responding
and controlling, and Living with acid and bases.
Purpose
By studying acids and bases, the students will become aware of the basic concepts, both terminology
and practical components, involved with acids and bases. The focus is not on the in-depth and
detailed chemical understandings, rather common applications and real life scenarios. As this section
is in the Medicine unit, the initial focus is on stomach acid, which leads into basic acid and base
concepts then onto household substances.
The digital content was used in the later part of the section after the students had explored, in a hands
on way, the experimental side of studying pH. The digital resource pH: What is pH? (L5815) allowed
for a comprehensive review of the areas that were covered during this section, including theory,
experimentation and deductions. Using this as a review to this topic was a different and engaging way
to see and hear the terms and language used in this area of science, as well as an introduction to the
more complex understanding of the in depth chemistry and basis of the pH scale. The digital resource
was supported, not only by the teacher, but also with a worksheet that encouraged students to record
data and make inferences and deductions.
As this unit had already been revised and published for this year, the digital resource and
accompanying worksheet were incorporated as an extra activity. As it is a visual interactive, it was
presented on an interactive whiteboard and strongly enhanced the unit. It also gave a very good
introduction to the mathematics around pH.
By simulating practical activities that were similar to the experiments that the students had performed,
the students were given a chance to practice forming hypotheses, thinking about method and making
inferences from results. By talking to students as the digital resource progresses, the teachers were
able to guide the students through experimental design and theory.
The reason I chose to use a hardcopy worksheet rather than just allow the students to work through
the digital resource individually was to allow for class discussion, pair and share and hope that all the
students would be able to understand the content at the same pace.
Duration
The Living with acids and bases component of the Medicine Theme runs over three weeks or
approximately 10 lessons. It is taught after the other topics outlined below.
What are acids?
Acids and teeth
Acids in food and drink
What is a base?
What is neutralisation?
The pH scale
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'Living with acids and bases' by Kerrith McGrath, Vic.
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Indicators
pH in your life
Homework Sheet 5 – Acid and Bases
Activity 9 - Common Indicators
Activity 10 - Natural Indicators
Activity 11- Measuring solids – Soil
Formal Practical Report 3 - Household Substances
The lesson in which the digital resource is used will take between 80-100 minutes (a double period).
Implementation
Context for learning
There are several contexts for learning within this unit and the digital resource, specifically
practice/consolidation, enquiry, application, assessment and formalisation.

Enquiry
This will be facilitated by students posing questions and being asked to explore, analysis and
predict what results would occur with each test.

Formalisation
The students will be writing answers on the worksheet.

Practice/consolidation
As the students have conducted some of the test in practical class, the digital resource will
allow the student to consolidate this knowledge.

Application
Students applied their understandings acquired from the digital resource by completing the
questions on the worksheet and answering verbal questions from the teacher

Assessment
The worksheets were marked, particularly the final question, where the students have to apply
the practical results to the unknown solutions. This section was not discussed in class and was
used as an indicator of which students fully understood the concepts that were covered.
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'Living with acids and bases' by Kerrith McGrath, Vic.
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Activity structure
This lesson was conducted in the laboratory with access to the Interactive Whiteboard. L5815 ph: what is pH? was on the screen when the students arrived.
Assessment
Time
Activity
Teacher Activity
Student Activity Resources
Preparation
Set up
3 mins
Introduction to
lesson
Handout
Digital resource
Start the interactive whiteboard and load the digital
resource. Mute the Data projector. Photocopy student
worksheets.
1. Asked directed questions about the activity we
conducted last lesson, guiding students to remember
about looking at acids in the stomach and the role of
indicators.
2. Outline of today's double period: Using the smart board
and an interactive simulation to introduce some of the
science in acid and bases and discuss how we are
going to use these substances and consolidate the
learning from the previous experiments during the next
few weeks.
Hand out worksheet and explain that as we go though the
lesson, they will need to fill in tables, write hypothesis and
predict what will happen. Also outline the rules of using the
smart board when they are asked to come up.
Open L5815 ph: what is pH?. Read out loud the instructions
and prompt students when to fill out sections of the
worksheet. Using strong questioning techniques, including
direct questions such as what colour would this indicator go
in an acid.
Also invite students to the Smartboard to conduct the
experiments outlined in L5815 ph: what is pH?
L5815 ph: what is pH?
Student worksheet
Active Listening
Informal question and
answer
Receive handout
and name
Ask students their
hypothesis/predictions
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'Living with acids and bases' by Kerrith McGrath, Vic.
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Learning resources
The digital resource
pH: What is pH?
TLF ID L5815
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Worksheet: What is pH?
Year 9 Science Manual – Medicine (school developed and published book.
Authors: K. McGrath, A. McMeeken and M. Payne)
Technologies
Interactive Whiteboard
Teacher reflection
The lesson progressed well. The students had not seen one of digital resources at Year 9 before, so
were engaged with the visual format. They were also excited about using the Smartboard; however
this became difficult to manage as the lesson progressed. Managing which student was to use the
board to conduct each test used considerable time, so in the end working through the digital resource
was entirely teacher led.
The questioning was a valuable tool to, not only in keeping students focused, but also in gauging the
existing knowledge of the students. For example, 'what colour should this indicator go in this particular
solution?' allowed student to show their understanding. Also predicting the order of the pH's
individually then in pairs was a valuable and non-threatening tool. As white out is not allowed, it is
easy to see which students were correct or incorrect when the worksheets were collected.
As the digital resource covered some concepts and equipment that the students had not been
exposed to in the lab, it allowed for, not only consolidation of ideas, but for students to learn concepts
in an established context. The digital resource complemented and enhanced our manual extremely
well and allowed us to introduce the concepts of hydronium ions (H3O+) and the ph meter. In future, it
would be good to then revisit these concepts, particularly the ph meter, by using the new data logger
pH meter.
The most valuable component of the digital resource was the last section in which the students were
asked to predict which solution matched with which pH. This allowed the students to apply their
knowledge to a new situation. As the teacher, I found that the digital resource presented the
foundation ideas and concepts very thoroughly and in very easy to understand terms, making this last
section a very good indicator of student understanding. Using real life solutions also assisted the
students in realising the application of the pH concept, which is a strong focus in Year 9 Science.
© Education Services Australia Ltd, 2010, except where indicated otherwise
'Living with acids and bases' by Kerrith McGrath, Vic.
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Other teachers subsequently utilized the lesson and found it very valuable as a revision and
consolidating tool. Due to the success of this resource, the worksheet and digital resource will be fully
incorporated into the manual for 2009, which will allow for easier collection and feedback, rather than
having separate sheets. Ideally a colour worksheet would have been better, but this will not be
possible.
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'Living with acids and bases' by Kerrith McGrath, Vic.
5
Worksheet: What is pH?
Name: ___________
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As you have recently discovered, acids and bases are chemicals that are in many everyday
substances, including inside your body. You will use this worksheet to record data,
predictions and facts about acids and bases as we go through L5815 pH: What is pH?
1. Properties of acids and bases
Acids






Base

Taste bitter

Change red litmus to blue

Change phenolphthalein indicator to
deep pink
Can be corrosive
Don't change red litmus – it remains
red
Don't change phenolphthalein
It remains colourless
Release hydrogen gas when added
to certain metals
2. Testing substances
Blue litmus
Red Litmus
Phenolphthalei
Metal test
n
Drain cleaner
Apple juice
Bicarbonate of
Soda solution
Battery acid
Salty water
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© Education Services Australia Ltd, 2010, except where indicated otherwise
'Living with acids and bases' by Kerrith McGrath, Vic.
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3. Predict the order of the substances from most acidic to most basic.
Refer to the above tables for information.
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4. What are the differences in results you get when using litmus and
phenolphthalein and universal indicator?
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'Living with acids and bases' by Kerrith McGrath, Vic.
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5. Fill in the gaps.
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6. Draw and label a hydronium ion (H3O+)
7. Fill in the following:
Concentration of hydronium
ions
pH
Acid or base?
1 x 10 -7
1 x 10 -12
1 x 10 -1
1 x 10 -8
8. Fill in the following finding table:
A
B
C
D
E
pH
Universal
indicator
colour
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'Living with acids and bases' by Kerrith McGrath, Vic.
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9. Work with the person next to you, using all the information and results, to predict
which solution is the unknown substance and justify why you have chosen this.
© Education Services Australia Ltd.
© Education Services Australia Ltd, 2010, except where indicated otherwise
'Living with acids and bases' by Kerrith McGrath, Vic.
9