Name: ______________________________________ Date: ________________________
Student Exploration: pH Analysis: Quad Color Indicator
Vocabulary: acid, acidic, alkaline, base, indicator, neutral, pH
Prior Knowledge Questions (Do these BEFORE using the Gizmo
1. Acids are substances that produce hydrogen ions (H
) when dissolved in water. Lemon
juice is an example of an acid.
A. What does lemon juice taste like? ________________________________________
B. What does it feel like if lemon juice gets in your eye? _________________________
2. Bases are substances that produce hydroxide ions (OH
) when dissolved in water. Hand
soap is an example of a base.
A. What does soap feel like? ______________________________________________
B. What does soap taste like? _____________________________________________
C. What does it feel like if soap gets in your eye? ______________________________
The strength of an acid or base is measured on the pH scale.
The term “pH” is short for “potential of hydrogen.” It is a measure
of how many excess H
ions there are in a solution. The pH scale
runs from 0 to 14, with 0 representing the highest concentration
of hydrogen ions. Acidic substances have a pH below 7, while
alkaline substances (bases) have a pH above 7. Pure water has
a pH of 7 and is considered neutral.
The pH Analysis: Quad Color Indicator Gizmo™ allows you to
find the pH of a variety of liquids. In the Gizmo, check that the
Substance in the tube is Ammonia, and click Test.
1. Indicators change color in acids or bases. What are the colors of the pH paper?
2. Compare the paper to the pH color chart. What is the pH of ammonia? ________________
Is ammonia acidic or alkaline? ________________________________________________
orange, coral pink, blue, yellow