ODS View Scenario/Lesson Plan Summary Page
Acids, bases and environment
Domain: alkalis and bases, Science>Chemistry>Chemical Reactions>Acids
|Learning objectives||Cognitive - Knowledge: |
Factual: Learn the pH scale.
Conceptual: Understand the concept of acid and base. Understand consequences of pollution at long terms.
Procedural: Improve experimental skills.
Cognitive - Process:
To remember: pH scale.
To understand: Acids and bases. Acid-base indicator.
To apply: Experimental activities.
To perform confidentially following instructions
|Grade & Age||13 to 15 years old. |
Grade: school education
|Keywords/subject||acid base pH laboratory security acidification |
|Prerequisites||The students need to understand what is a chemical reaction.
They will need some experimental skills and knowledge of basic laboratorial materials. |
|Author(s)||Name: Miguel Neta Organization: Agrupamento de Escolas Dra Laura Ayres Role: Physics and Chemistry teacher |
|Description/ main idea|| |
The teacher introduces the subject of acids, bases and the pH scale;
The students, with their parents help, analyze some materials at home to compare their acidity or basicity using a homemade pH indicator;
Students observe the relation between human behavior (polution) and ocean acidity.
Final presentation of some of the parents-students works.
- pH scale
- pH and Color Change
- Good Laboratory Practice video
- Good Laboratory Practice
- Homemade pH indicator
- Red cabbage indicator
- Experimental pH indicator activity
- Heureka Colourful Chemistry
- Water acidification
- Acidification of water
- Polution and ocean acidification
- Final presentation
Demonstrative activity of the pH scale.
Multimedia materials will be used to explain the modification of the acid-base indicator color.
pH and Color Change
"Students will see a demonstration of a color change using universal pH indicator. Students will see an animation showing that water molecules interact and separate into the H3O+ ion and the OH− ion. Students will see that the pH of a solution is related to the concentration of these ions in water."
Lesson plan available at: http://www.middleschoolchemistry.com/lessonplans/chapter6/lesson8
(The American Chemistry Society lesson plan should be adapted to be an demonstrative activity.)
Educational objects (as url):
1. pH and Color Change
2. Related multimedia
Good Laboratory Practice video
The students needs ot be prepared to use some laboratorial material with security.
A video should be seen by students with their parents, at home, before the next phase.
Good Laboratory Practice
Video about good laboratory practice:
Educational objects (as url):
1. Good Laboratory Practice Video
Homemade pH indicator
Students and their parents will be able to make a homemade pH indicator and use it to control the acidity/basicity of some daily use materials.
They should be instructed by the teacher to make pictures of their work for a presentation to others parents and students.
Red cabbage indicator
The students will work with their parents to make a pH indicator and then use it to see the kind of solutions they use at home (acids, bases or neutral).
The procedure is available at: http://chemistry.about.com/od/acidsbase1/a/red-cabbage-ph-indicator.htm
and a video at: http://video.about.com/chemistry/Cabbage-pH-Indicator.htm
Students and parents should take pictures of their work so they can present it later.
(Some laboratory material will be replaced with home materials... beakers for glass cups, for example.)
Experimental pH indicator activity
The students will use the 'Heureka Colourful Chemistry' (www.xplora.org) to make experimental use of pH indicator in laboratory materials/solutions.
Heureka Colourful Chemistry
Use (after adapte for a specific class and the materials of each school) the lesson plan available at: http://www.xplora.org/shared/data/pdf/chemistry_colour.pdf
Students should take photos during their work to present it later.
Duration1 Hours & 3 Minutes
After students understand the use of pH indicatores to test solutions they will observe the consequence of the solubility of CO2 in water.
Acidification of water
Students will observa the acidification of water by the presence of CO2.
The lesson plan 'Carbon dioxice can make water acid' is available at: http://www.middleschoolchemistry.com/lessonplans/chapter6/lesson10
Students can understand the reaction
Educational objects (as file):
1. CO2 reaction with water
Polution and ocean acidification
Students are asked to think about relation with previous activity and human behavior (polution) and ocean acidity.
This task is made in small grups for later presentation.
Parents are invited to present the work that they have done with their children at home at a non formal reunion.
A group of small students present a report about how human polution is changing ocean water pH and consequences of that change.
Teacher, parents and students can change ideas during a brief informal meeting (drinks and snacks are a good idea!).
Students and parents use the pictures that they have taken to make a brief presentation about how their work at home.
Each group organise the tested materials in grups (strong acids, weak acids, neutral solutions...).
They talk about difficulties that they have encontered.