The following is a lesson sequence which modified the above experiment to promote inquiry based learning process.
The aim of the experiment: Students use the change in the colour of red cabbage indicator to classify substances as either acid or base.
Note: This activity may take more than one lessons. On the first lesson, students group, discuss and prepare their experiment. On the second lesson, students will have opportunities to carry out the investigation, then record, process, and evaluate their data.
Preparing materials
In the original experiment, hydrochloric acid and sodium hydroxide solutions have been used as acidic and basic solution, respectively. However, year 9 students might know that hydrochloric acid solution is an acid and …show more content…
For instance, how can you tell if a substance is an acid, a base or neutral?. Teacher could then assist students to apply their prior knowledge to answer the questions and further explore the issues through a series of questions which relate the role of indicator to the identifying of acidic/basic/neutral substances. For example, how indicator is used to identify acidic/basic/neutral substances? What is the colour of indicator in acidic/basic/neutral solutions? At the end of the discussion, teachers should provide students the summary that when a certain chemical are added to an indicator, its colour will be changed. It turns pinkish when it is mixed with acids. It turns green when it is mixed with bases. And it does not change the colour when it is mixed with neutral substances. Moreover, teachers should then show students the materials for the experiment and question to make them to predict the purpose of each material. For example, what is the cabbage used for? What is the state of the indicator? What would be the colour of the cabbage? How could you extract the cabbage’ colour? How do you use the cabbage solution to test the acidity/basicity of unknown substances? Teachers then have students to discuss to write up a procedure for the experiment. It should be noted that teachers have to make sure that they check the proposed procedure of each student group. Teacher should also …show more content…
What do we add in the control test tube?
How do you add household substances in to the test tube?
How do we remember our observation for each reaction?
Section 2. Have students prepare for and perform the activity
While students are doing the activity, teachers need to walk around in the classroom to supervise and help students in case that they need more clarification for the issue. Furthermore, teachers can make formative assessment processes while observing the students’ performance of the investigation.
Section 3. Have students process, analyse and share their conclusion.
Students should discuss with their group about their observations and how they described their observations. They should also work together share the answers and explanation for the questions in the Discussion section of the original experiment. Teachers can also add some more questions such as “What is the relationship between the colour of red cabbage indicator and strength of acid/base in the household substances?” to support students develop their understanding of the topic more deeply. Moreover, students must provide a conclusion based on their result.
Section 4. Problems/accidents in the
The aim of the experiment: Students use the change in the colour of red cabbage indicator to classify substances as either acid or base.
Note: This activity may take more than one lessons. On the first lesson, students group, discuss and prepare their experiment. On the second lesson, students will have opportunities to carry out the investigation, then record, process, and evaluate their data.
Preparing materials
In the original experiment, hydrochloric acid and sodium hydroxide solutions have been used as acidic and basic solution, respectively. However, year 9 students might know that hydrochloric acid solution is an acid and …show more content…
For instance, how can you tell if a substance is an acid, a base or neutral?. Teacher could then assist students to apply their prior knowledge to answer the questions and further explore the issues through a series of questions which relate the role of indicator to the identifying of acidic/basic/neutral substances. For example, how indicator is used to identify acidic/basic/neutral substances? What is the colour of indicator in acidic/basic/neutral solutions? At the end of the discussion, teachers should provide students the summary that when a certain chemical are added to an indicator, its colour will be changed. It turns pinkish when it is mixed with acids. It turns green when it is mixed with bases. And it does not change the colour when it is mixed with neutral substances. Moreover, teachers should then show students the materials for the experiment and question to make them to predict the purpose of each material. For example, what is the cabbage used for? What is the state of the indicator? What would be the colour of the cabbage? How could you extract the cabbage’ colour? How do you use the cabbage solution to test the acidity/basicity of unknown substances? Teachers then have students to discuss to write up a procedure for the experiment. It should be noted that teachers have to make sure that they check the proposed procedure of each student group. Teacher should also …show more content…
What do we add in the control test tube?
How do you add household substances in to the test tube?
How do we remember our observation for each reaction?
Section 2. Have students prepare for and perform the activity
While students are doing the activity, teachers need to walk around in the classroom to supervise and help students in case that they need more clarification for the issue. Furthermore, teachers can make formative assessment processes while observing the students’ performance of the investigation.
Section 3. Have students process, analyse and share their conclusion.
Students should discuss with their group about their observations and how they described their observations. They should also work together share the answers and explanation for the questions in the Discussion section of the original experiment. Teachers can also add some more questions such as “What is the relationship between the colour of red cabbage indicator and strength of acid/base in the household substances?” to support students develop their understanding of the topic more deeply. Moreover, students must provide a conclusion based on their result.
Section 4. Problems/accidents in the