Science Class 7
Exploring Substances: Acidic, Basic, and Neutral
Acid, base or neutral? Test with litmus and turmeric — never by tasting.
14 lessons · ~61 min total
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Lessons in this topic
- 0 Start here Every substance is acidic, basic or neutral — and a paper strip finds out which. · 3 min You are here
- 1 Three groups, and no tasting Every substance is acidic, basic or neutral, and a litmus strip tells you which. · 4 min
- 2 Acids in our food Sour foods tend to hold an acid. Each has its own common acid. · 4 min
- 3 Bases around us A base turns red litmus blue. Bitter taste alone does not make a base. · 4 min
- 4 Turmeric paper and red rose Turmeric turns red in a base only. Red rose shows red, green or no change. · 5 min
- 5 No change is an answer too A neutral substance changes neither litmus. One unchanged strip is not enough. · 5 min
- 6 An acid and a base cancel each other Add just enough base to an acid and it turns neutral. Add more and it turns basic. · 5 min
- 7 Checkpoint: groups, strips and neutralisation A quick graded check on the first six ideas. · 4 min
- 8 Indicators from plants Every indicator has its own colours. Learn them first. · 5 min
- 9 Indicators you can smell Some indicators change smell. Onion fades in a base. · 4 min
- 10 Neutralising soil and waste Lime fixes acidic soil. Treat acidic waste first. · 5 min
- 11 Checkpoint: plant indicators, smell and soil A quick graded check on plant indicators, smell and soil. · 4 min
- 12 The big picture The whole chapter on one screen. · 3 min
- 13 Track quiz Eleven quick questions on acids and bases. The nine rules are at the top. · 6 min
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