Young Macdonald's Farm PH -- Lesson Plan #2 Checking different pH levels Introduction Students will use the pH scale to check water samples that contain a range from 2.2 (lemon Juice) to 12.4 (lime Juice) Objective To show students how to use a pH scale and test comminuted water Materials pH Kit Lemon Vinegar Distilled water Tap water Baking soda Ammonia Lime Beakers Procedure Demonstrate how to use a pH kit Give students a sample of distilled water and have them check the pH level 7.0 Draw a pH scale on the chalk board numbered 0 to 14 Showing students 7 is neutral on the pH scale pH Base 0-------------------neutral 7------------------Base 14 Make Mixtures of sampled water With the following ingredients: Setup 5 separate beakers each with 8 oz of water add- 3 drops of lime juice to beaker #1 3 drops of lemon juice to beaker #2 3 drops of vinegar to beaker #3 3 drops of ammoniate beaker #4 1/2 table spoon of baking soda to beaker #5 Have students use pH kit to sample all of the water in beakers 1 through 5 Have student s record their answers on data table Have students clean up work area Start to have students explain their results Use the pH scale on the chalk board to label students results Discussion questions 1. Which was the lowest reading you had on the pH scale? (2.2 lemon juice) Is this and acid or a base? Then explain why. 2. Which was the highest reading you had on the pH scale? (12.4 lime juice) Is this and acid or a base? Then explain why. 3. Why do we need to know is something is an acid or a base from the pH scale? 4. Why is it important to understand the difference between acid, neutral or base when it comes to rain? Science Teacher: Mark Talty