Science 14
Acid and Bases Around You LAB
Unit 1
 In this activity you will use litmus paper to test whether a mixture is an acid or a base. Then you will
use universal pH paper to determine the exact pH of the mixture.
 Litmus paper changes colour depending on the substance being tested.
o
Litmus paper will change to a blue colour in the presence of a base.
o
Litmus paper will change to a red colour in the presence of an acid.
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Problem: Which common household solutions are acids? Which are bases? What is the pH of each?
Procedure:
1. Beside each substance being tested, predict if you think the substance is an acid or a base.
2. Gather 10 small strips of litmus paper.
3. Gather a couple pieces of paper towel.
4. At each station dip the litmus paper in the substance for about 10 seconds then remove
and observe any colour change.
Be sure to put the paper towel under the test strips so you do not spill any substances
on the counter tops.
5. Record the change in colour of the litmus paper in the correct column of the table.
6. Compare the change in colour to the pH key provided to determine the approximate pH of
the substance. Record this in the table.
7. Fill in the last column of the table, is the substance an acid or a base?
8. Repeat for the remaining substances
Science 14
Unit 1
Results Table:
Substance
Predication
Litmus Paper
Colour Change
pH According
to the pH key
Acid, Base, or
Neutral
Ammonia
Melted Snow
Soap
Vinegar
Tums Tablet
Baking Soda
Fruit Juice
Bleach
Milk
Answer the analysis questions #1-10 on page 67-68 of your textbook.