Acids and bases

Title: What is PH

Author: Cota

Subject: Science

Grade: 6

Week:

Unit/Lesson Plan #:

Unit theme:

Textbook references:

Learning objectives:

Acids are a class of compounds that have a sour taste and react with bases and metals.

Bases are a class of compounds that have a bitter trate and react with acids.

Acids and bases can be detected by natural dyes called indicators

Key Questions, Concepts, or Themes:

Acids

bases

indicators

neutralization

Stage 1:

Gettting started: Fill a large beaker halfway with lemon juice. Telll students that lemon juice is an acid. Add a few drops of universal indicator to the beaker. Ask them what they think will happen if you add an antacids tablet to the beaker? Grumble the antacids into the beaker.. the color will change. Explain that the acidic lemon juice was neutralized by the basic antacids tablet.

Stage 2:

The determination of the pH of a substance is the measurement of the H+ ions found in that particular substance. pH is determined and recorded as a number between 0 and 14. Pure deionized water has a pH of 7 which is neutral. This means that the level of H+ and OH- ions in pure water are equal If the level of H+ ions increases, the substance is considered an acid and the pH number is below 7. If the level of OH- ions increases, the substance is considered to be alkaline or base and the pH number is above 7.

An acid has a range of 0 to any numerical value below 7. For example, 6.9 would be a weak acid. A base has a range of any numerical value above 7 to 14 with 7 being a neutral value. A one-unit change in the pH, from 4 to 3, is a ten-fold change in how acidic the substance has become. This means that a pH of 3 is ten times more acidic than a pH of 4.

Stage 3:

How is PH determined?

Lab:

exploration 1 page 294-295

Homework: No homework in this class?

Assessments: (attach/link copies)

__ Group assessment

__ Observation of process/student work

__ Self-assessment by student

__ Teacher generated assignment

__ Written project

__ Test/Quiz

__ Other: ____________________________________