Acids, bases and pH are core chemistry concepts that are introduced in elementary level chemistry or science courses and expanded upon in more advanced courses. This chemistry lesson plan covers essential acids and bases terminology and offers students hands-on experience testing common home chemicals to determine whether they are acids, bases or neutral.
Time RequiredThis lesson can be completed in 1-3 hours, depending how in-depth you decide to get.
Educational LevelThis lesson is best-suited for students at the elementary to middle school level.
- red (purple) cabbage
- coffee filters
- household chemicals with a variety of pH levels. You can use this pH scale for ideas. Good choices include diluted ammonia, laundry detergent, milk, vinegar, water, soft drinks and lemon juice.
Acids and Bases Lesson Plan
- Explain what is meant by acids, bases and pH. Describe characteristics that are associated with acids and bases. For example, many acids taste tangy. Bases often feel soapy when rubbed between your fingers.
- List the materials that you've gathered and ask students to predict, based on their familiarity with these substances, whether they are acids, bases or neutral.
- Explain what is meant by a pH indicator. Red cabbage juice is the indicator used in this project. Describe how the color of the juice changes in response to pH. Demonstrate how to use pH paper to test pH.
- You can prepare pH solution or strips in advance or make this into a class project. Either way, have students test and record the pH of a variety of household chemicals.
- You may wish to provide an "unknown" and have students determine approximate pH. Based on the pH, is this an acid or a base? From a list of three chemicals with different pH values and characteristics, ask students to select the identity of the "unknown" sample.
- Have students research pH indicators and identify other common household chemicals they might use to test pH instead of using red cabbage juice.
- Ask students to explain, in their own words, the difference between acids and bases. What is meant by "neutral"? What does pH measure?