TEACHING RESOURCES TEST INFORMATION
NAME AND SURNAME
Brajkovic Divna
AFFILIATION
HELMo Ste Croix
ROLE IN THE PROJECT
Expert
TITLE OF TEACHING RESOURCE
A learning sequence “Discovering the chemical reaction” (3rd secondary year).
Topics related to the resource
This resource addresses the notion of chemical reaction at the qualitative (defining and identifying a chemical reaction) and quantitative (the law of conservation of mass).
Examples of learning objectives
The objectives are targeted for each activity in the document “sequence structure”. They are listed below for each paperboard (title in bold) according to the mission proposed to the student.
1. Situation
Objectives:
o Asking questions
2. How to define a chemical reaction?
Mission 1: reproduce the “magic trick”
Objectives:
o To design an experimental procedure from the products and material at one’s disposal
o To conduct the experiment respecting security rules
o To analyse the results
o To write a report
Mission 2: explain the “magic trick”
Objectives:
o To build molecule models with the help of molecular models (cfr. Tool sheet)
o To make hypotheses on the molecules obtained at the end of the phenomenon
o To design an experimental procedure to check the hypotheses
o To model a chemical phenomenon with the help of molecular models and boxes (cfr. Photo in the attached document)
o To translate the model into chemical equation
o To infer a temporary definition of the chemical reaction
3. Searching the chemical phenomena
Mission 3:
Objectives:
Among the following phenomena (7), detect the chemical reactions.
o To observe a phenomenon
o To describe the observations
o To observe a flash animation in order to model or explain what happens at the microscopic level
o To define a chemical phenomenon and a physical phenomenon
o To identify a chemical/physical phenomenon at the macroscopic and microscopic levels
o To use the IWB (videos, screen captures, flash animations...) to communicate one’s analysis of a phenomenon at the macroscopic and microscopic levels
4. Is mass conserved during a chemical phenomenon
Mission 4: check the law of conservation of mass
Objectives:
o To experiment following an operational mode and respecting security rules
o To analyse the results
o To write a report
o To think of a way to check the law of conservation of mass in an enclosed environment.
Mission 5: check the law of conservation of mass for the magician’s trick!
Objectives:
o To experiment following an operational mode and respecting security rules
o To analyse the results and compare two experimental processes
5. How to represent a chemical reaction?
Objectives:
o To define a chemical equation at the macroscopic and microscopic levels
o To write, read and balance a chemical equation
6. Exercises
Objectives:
The exercises are used to practise knowledge and skills acquired all along the sequence
At the end of the sequence, an evaluation is proposed in the form of a task (called “science journalist”)
This integration situation makes it possible to assess the skills of two families of tasks: FT1 and FT2
(FT1: To describe, explain a phenomenon or how an object works, to predict the evolution of a phenomenon
FT2: to carry out an experimental approach)
Practical information regarding the use
of the site/simulation...
Information about the class
The resource was tested in a 22 student class, first year Sciences “régendat” (future science teachers) at Haute Ecole Libre Mosane Sainte-Croix (HELMo Ste Croix).
Suggestion for use
Here is an analysis in a table (see attached document) to visualise in parallel the steps of the investigative approach, one part of the educational scenario and the use of ICT.
The first step, very important to develop the investigative approach, is questioning. A “show” experiment is used to raise questioning. A “magician” (a former third year student, Sandrine Charlier) make a piece of magnesium, a metal, disappear, in a clear and colourless solution.
Thanks to ICT, the situation can be presented from a video, allowing a first visualisation of this complex dynamic phenomenon at the macroscopic level.
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Then, the students’ preconceptions/questions phase to command questioning can be done on the IWB. The IWB allows to save date, go back and forth, which is important for the principle of unity and diversity of an investigative approach.
Now students are ready to reproduce the “magic trick”. They have several solutions and liquids at their disposal. They must design a protocol to reproduce the trick. This step is important so that students observe and analyse the studied phenomenon. This phase will help them imagine an experimental protocol and confront their preconceptions to reality. Thanks to the IWB, students can put their positive/negative results in common.
Within the framework of my experimentation, 1st bac student did not think it necessary to reproduce the phenomenon becau they know this reaction well.
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Then, they must make hypotheses on the products formed, modelling the substances obtained after the “vanishing” with non-virtual models. To do so, they have modular boxes (before and after the phenomenon), paper cotillons and toothpicks (that can be replaced by molecular models). This step is important because it is the first transition to abstraction.
It is a “conceptualisation” type modelling to make phenomena as simple as possible, in order to make out the concepts more easily (conceptual models) and thus help students build a mental representation of these. It is unavoidable in chemistry to help students overcome their understanding difficulties.
On the IWB, the different hypotheses can be put in common with the help of virtual models, models created thanks to the functionalities of the IWB. This confrontation of hypotheses is interesting to confront/enhance the points of view and clarify some students’ hypotheses.
Indeed, many students have difficulties during this step. I was astonished to see how difficult it was to model salt (MgCl2) and gaz (H2) produced while they should normally know this reaction. I think their mistake was not to entre directly in the investigative approach dynamics. They did not ask questions in the beginning and did not deem it necessary to reproduce the phenomenon they thought they knew. Should it be done again, I would ask them more questions related to their daily life (for instance: in everyday life, have you observed solids that “disappear” in solutions?) to check their preconceptions and go back to it during knowledge consolidation. Moreover, I would ask them to reproduce the reaction and to spray the water contained in the solution to view the formed salt. In this way, I hope they would keep in mind the necessary observations at the macroscopic level before they start modelling.
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Based on the resources (chemical tests to identify gas and ions in aqueous solution), the students propose written manipulations to confirm their hypotheses. This approach must be validated by the teacher before it is carried out.
This phase was produced in writing by the students. It did not cause particular problems. There is no ICT at this step.
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The investigative phase: the students test their hypotheses doing the planned manipulations at their own pace. If the identification tests do not confirm their hypotheses, they can do experiments again. There is no ICT in this mostly experimental phase but they could be considered for information research.
The students really carried out the investigation in a rigorous way, asking the right questions and going back to their hypotheses if necessary.
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The investigation analysis, in a table, is used to analyse the phenomenon at the temporal level as well as macroscopic, microscopic and symbolic levels. The student models/mimics with non-virtual models (before, during and after) the reaction to try and write the chemical equation of the reaction and define what a chemical reaction is. This step is important for the students to picture and integrate the gradation of the abstraction levels.
There is no ICT in the analysis. Indeed, animations are relevant to illustrate the dynamics of a phenomenon but they should not disturb the investigative approach [5].
In this step the students can structure what they have learnt. It is interesting to analyse the students’ productions because some go beyond the learning objective considering the ions present in the solution. However (cfr. photo), a major confusion remains concerning the chemical writing of solid magnesium. Either students write it as an ion, or they write Mg2 since magnesium has valence 2! They mix up the notions of ion, molecule and atom at the level of modelling and symbolic writing; experiencing this approach is therefore important.
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Structuring is done in the form of questioning with the help of videos and animations. The video makes it possible to view the macroscopic level, chemical tests carried out before making the link with the microscopic level. The flash animation makes it possible to view the complex dynamic phenomenon at the molecular level. Important moments of the phenomenon can be identified before, during and after (with screen capture) in order to gradually bring students to the symbolic writing of the chemical equation.
Thanks to those resources, it is possible to correct the analysis table created by the students and the conclusions conclusion, that is, the temporary definition of the chemical reaction. Moreover, during this phase the students discover new functionalities of the IWB (flash animations, screen captures, models on IWB) they will need to use during the next step.
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Based on this “temporary” definition of the chemical reaction, the students will analyse in groups other phenomena to ascertain they are chemical reactions. To do so, they must analyse videos and flash animations and present their analysis to the classroom using the IWB.
This step of knowledge consolidation was carried out successfully; the students could acquaint themselves with the functionalities of the IWB during the oral presentations in groups.
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At the end of the sequence, a task (integration situation) evaluates some of the skills achieved.
This task was party proposed to the students during the chemistry training exam one month after the experiment.
Insights into student
use / thinking
After the experiment, a questionnaire on e-learning was used to review the strengths and weaknesses of the scenario.
Here is a short review of the answers:
1. What did you discover you did not know at the beginning of this sequence?
- 2 main answers: using the IWB and refreshing/exploring knowledge.
- 1 answer on didactics: a student feels this scenario gives her possibilities to address chemical reactions with her future students.
2. At which specific moment of the process?
- 8 answers mention knowledge consolidation, thus during the presentation in front of the peers with the IWB.
3. What in particular helped you discover it?
- The answers are varied but experimentation and the IWB slightly prevail.
4. What was the most difficult for you in this sequence?
- 2 difficulties are mentioned: sorting chemical and physical everyday life phenomena and modelling (atomic level) thus making hypotheses.
5. Have you got comments for the teacher?
- 6 very positive answers (it was a nice activity and it helped me remember; all the steps of the sequence are important and help students better understand)
It is interesting to see the usefulness of this experimentation that solicits knowledge normally achieved at the end of secondary school.
Generally speaking, students point out this scenario helped them refresh the subject and learn how to use the IWB Those learnings were built especially during the oral presentations in group supported by the IWB. According to them, learning is made easier by experimentation and the use of ICT. Mentioned obstacles to learning correspond to my observations. They concern modelling during hypotheses. Besides, during knowledge consolidation exercises, some students had difficulties to analyse everyday life examples.
Teacher’s conclusions
According to those first experimentations, based on a limited number of students, I will sum up temporary conclusions:
Regarding the creation of learning scenarios integrating ICT:
To foster chemistry learning, learning scenarios should specifically integrate ICT (videos, animations, IWB…) to support the investigative approach for a gradation of abstraction levels. Those learning scenarios would help develop scientific, technical and transversal skills.
In the experimented learning scenario, ICT resources, integrated in the IWB, are mainly used:
- In the beginning during the phases of questioning and common gathering of students’ hypotheses,
- At the end for structuration and knowledge consolidation.
However, depending on the topics, ICT can be used at other moments of the process. Without replacing real experimentation, ICT can support the investigative approach at different moments of the process. Indeed, the main asset of ICT to support the investigative approach is the improved analyses of complex dynamic phenomena at the macroscopic level (with videos) and their modelling at the atomic and molecular levels (flash animations or others) to make the transition from the macroscopic to the microscopic level easier.
ICT integrated to the IWB have other assets to support the investigative approach.
Regarding the assets of the IWB:
Bétrancourt’s (2007) typology on the use of ICT makes it possible, when adapted, to present the assets of the IWB in relation to the investigative approach. The four main categories are built on a student-centred educational approach.
The diagram in the attached document shows the most specific asset of the IWB, in the centre, interactivity, to which other assets, to be moderated, can be added: information stocking and use; information visualisation; production and creation process; automatic processing of complex information.
