1. S1 Science Acids and Bases
REVISION
I have investigated different
water samples from the
environment and explored
methods that can be used to
clean and conserve water and
I am aware of the properties
and uses of water.
SCN 2-18a
NEW LEARNING
Having taken part in practical
activities to compare the
properties of acids and bases,
I have demonstrated ways of
measuring and adjusting pH
and can describe the
significance of pH in everyday
life.
SCN 3-18a

7. Explain what the pH scale is
Learning what pH is used to measure. Colouring in a pH
scale to show the different values. Watch a video to show
us how to measure pH

8. What are acids and bases?
You may not have heard
of bases but you’ve
probably heard of acids
Acid – a substance with a pH less than 7
Bases – a substance with a pH more than 7

9. The pH Scale
The pH number of a substance is linked to how concentrated an acid or base is
Water is neither acid nor base so is pH 7, in the middle

10. The pH scale extends from pH 1 to pH 14.
To find out pH you must use an indicator like UNIVERSAL INDICATOR.
Most indicators change colour dependent on pH.
The diagram below shows how colour with universal indicator links to pH number and how acidic or alkaline a substance is.

11. What is an indicator?
Indicators work simply by changing colour when they come into contact with certain substances
They are used to show if a substance is acidic, alkaline or neutral

12. Indicators
Indicators in general come from plant materials .e.g. beetroot, blackcurrants or brightly coloured flower petals
Universal indicator is a mixture of several indicators.

13. How to test acids and alkalis

14. Explain what the pH scale is
Learning what pH is used to measure. Colouring in a pH
scale to show the different values. Watch a video to show
us how to measure pH

15. S1 Science Acids and Bases
REVISION
I have investigated different
water samples from the
environment and explored
methods that can be used to
clean and conserve water and
I am aware of the properties
and uses of water.
SCN 2-18a
NEW LEARNING
Having taken part in practical
activities to compare the
properties of acids and bases,
I have demonstrated ways of
measuring and adjusting pH
and can describe the
significance of pH in everyday
life.
SCN 3-18a

16. Starter Questions What does the pH scale measure?
It measures how acidic a substance is
What colour is a neutral solution on the pH scale?
Green

17. Measure how acidic substances are.
Learning what the pH of a substance is and doing
An experiment to measure the pH of some everyday
substances.

18. What is a hazard? A hazard is something that can cause you danger
We should use symbols to represent hazards because it’s easy to understand
Symbols are brightly coloured so that you notice them

20. Testing the pH of substances
For liquids use a dropper to put a few drops on a dimple tray
For solids use a spatula
Add 3 drops of universal indicator
Do not stir solids – this can change the colour

21. Note down the colour and compare this to the chart you’ve been given
Acids – red, orange, yellow
Neutral – green
Alkali – dark green, blue, purple
Substance
Colour
Acid, neutral or alkali

23.
Test the pH of common household substances

24. Measure how acidic substances are.
Learning what the pH of a substance is and doing
An experiment to measure the pH of some everyday
substances.

25. S1 Science Acids and Bases
REVISION
I have investigated different
water samples from the
environment and explored
methods that can be used to
clean and conserve water and
I am aware of the properties
and uses of water.
SCN 2-18a
NEW LEARNING
Having taken part in practical
activities to compare the
properties of acids and bases,
I have demonstrated ways of
measuring and adjusting pH
and can describe the
significance of pH in everyday
life.
SCN 3-18a

26. Starter Questions Name a household acid
Vinegar, tomato sauce, lemon juice etc.
Name a household base
Bleach, toothpaste, bicarbonate of soda

27. Describe how household acids are different from
laboratory acids
Learning the names of some common laboratory
acids, carry out an experiment with these acids

28. Acids
A household acid is something that we find at home e.g. vinegar, tomato sauce, orange juice etc.
A laboratory acid is one that is used in the laboratory. Common laboratory acids include hydrochloric acid, sulphuric acid and nitric acid

30. Experiment
Test the pH of some household acids and compare them to the pH of laboratory acids
Substance
pH number

31. Questions
Generally which is more acidic, household acids or laboratory acids?
You put vinegar on your chips, but would you put hydrochloric acid (or any laboratory acid) on food and eat it? Explain your answer.

32. Describe how household acids are different from
laboratory acids
Learning the names of some common laboratory
acids, carry out an experiment with these acids

33. Starter Questions
Is vinegar an acid or base?
Is cola an acid or base?

34. S1 Science Acids and Bases
REVISION
I have investigated different
water samples from the
environment and explored
methods that can be used to
clean and conserve water and
I am aware of the properties
and uses of water.
SCN 2-18a
NEW LEARNING
Having taken part in practical
activities to compare the
properties of acids and bases,
I have demonstrated ways of
measuring and adjusting pH
and can describe the
significance of pH in everyday
life.
SCN 3-18a

35. Describe what a base is, explain that an alkali is a
special type of base
Learning the names of some common laboratory bases, carry
out an experiment with these bases

36. Bases Most of you will have heard of acids before
How many of you have heard of bases?
They are used everyday too

37. Household bases Some cleaning products have a pH
MORE than seven. This means
that they are a base
Oven cleaner
Bleach
You wear gloves because bases
can be corrosive just like acids

38. Common Bases
Test the pH of some household bases and compare them to the pH of laboratory bases
Substance
pH number

39. What is an alkali? An alkali also has a pH of more than seven
How is it different from a base?
Both have a pH of more than seven, but alkalis also dissolve in water

40. Alkali
Also dissolves
in water
Base
pH more than 7

41. Try these two bases…
Add half a spatula of sodium oxide to a test tube then add water – what happens?
Add universal indicator and note the colour
Next add half a spatula of sodium carbonate to a test tube then add water – what happens?

42. Questions
Explain what happened when you added water to the sodium oxide
Can we call this an alkali as well as a base?
Explain what happened when you added water to the sodium carbonate

43. Put these alkalis into a table. Decide if they Are household
alkalis or
laboratory (lab)
alkalis
sodium hydroxide
lime water
ammonia solution
bicarbonate of soda
oven cleaner
dishwasher powder
bleach
hard soap
Household
Lab
sodium hydroxide
lime water
ammonia solution
bicarbonate of soda
oven cleaner
dishwasher powder
bleach
hard soap