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Acid or alkali? Acidic or alkaline?

Description

This simple experiment involves testing a variety of substances to see if they are acidic or alkaline, using litmus paper as the indicator.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
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Apparatus Chemicals

Eye protection

Watch glasses, 1 per sample (Note 1)

White tiles, 1 per sample (Note 1)

Red and blue litmus paper, 3 pieces of each per working group

Access to small amounts of common everyday substances such as (Note 2)

fizzy drinks

tap water

de-ionised/distilled water

toothpaste

shampoo

soap

vinegar

lemon juice

Refer to Health & Safety and Technical notes section below for additional information.

 






This simple experiment involves testing a variety of substances to see if they are acidic or alkaline, using litmus paper as the indicator.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology.

If you teach primary science, click the headings below to find out how to use this resource:

Skill development

Children will develop their working scientifically skills by:

  • Selecting and planning the most appropriate ways to answer science questions, recognising and controlling variables where necessary, including:
    • grouping and classifying things.
  • Recording data and results using scientific diagrams, labels, classification keys and tables.
  • Using appropriate scientific language and ideas to explain, evaluate and communicate their methods and findings.

Learning outcomes

Children will:

  • Make predictions and test a variety of substances to determine if they are acidic, alkaline or neutral.

Concepts supported

Children will learn:

  • Substances can be acidic, alkaline or neutral
  • Substances can be grouped according to their properties including whether they are acidic, alkaline or neutral

Suggested activity use

You could carry out this activity as a carousel of different stations, allowing the children to work in pairs or threes to make predictions and then test a range of common everyday substances to see if they are acidic or alkaline. Children can then decide how to record this information and discuss their findings as a plenary activity.

Practical considerations

Various equipment and resources are needed for this practical, including litmus paper and watch glasses.

To get the most out of the activity, children will need some simple understanding of the terms acid (noun), acidic (adjective), alkali (noun), alkaline (adjective), neutral (adjective) and indicator.