Acids, Bases and pH: Test Virtual Liquids
Understand that pH measures how acidic or basic a solution is on a logarithmic scale from 0 to 14, that indicators change colour over a range, and that dilution moves a solution toward neutral without crossing it.
Before you try
What if you kept adding water to lemon juice? Could you turn it into a base?
Try it out
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What happened?
Move a control to see what changes and why.
The pH values are typical figures at room temperature. Real samples vary, and warming a liquid shifts its pH.
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Try these ideas
- Test lemon juice with red litmus and then with blue litmus. Which one changes?
- Add water to bleach and watch how far the pH moves toward 7.
- Use phenolphthalein on an acid and on a base and compare.
Why it works
Acids have more hydrogen ions than pure water, bases have fewer, and pH is a compact way of saying how many. The scale runs from 0 to 14 with 7 as neutral, and it is logarithmic, so each step of one means ten times more or fewer hydrogen ions. That is why pH 2 is a hundred times more acidic than pH 4, not twice as much.
In this simulator you pick a liquid, choose an indicator and add water. The beaker colour, the pointer on the pH scale and the hydrogen ion concentration all update together. The pH values are typical ones for these liquids rather than measurements, and the dilution rule is simplified: real weak acids move less than a full unit for each tenfold dilution.
Check your understanding
Question 1 of 4
How much more acidic is pH 3 than pH 5?
You keep diluting vinegar with water. What happens to its pH?
Blue litmus paper turns red. What did you test?
Which of these is a base?
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
What will you discover next?
Try Solutions and Solubility: How Much Will Dissolve? next.
For parents & teachers
- Test kitchen liquids with red cabbage water and compare the colours.
- Ask why toothpaste is slightly basic.
- Discuss why farmers test the pH of their soil before planting.