Reaction rates

The Reaction rates SAILS inquiry and assessment unit uses effervescent vitamin C tablets to introduce students to the concepts of gas production in the reaction of acid with carbonate, and rates of reaction and factors influencing reaction rate. Three activities aimed at lower second level are outlined, although they can be further extended and adapted for upper second level. The activities can be carried out in a sequence of lessons, which would require about ten class periods, or a specific activity can be targeted, requiring about two class periods depending on the skills to be assessed.

The first activity seeks to challenge students with collecting and identifying a gas, while the second activity explores quantitative measurements and graphical representation of data. The final activity explores identification of variables that may affect measurements. Students can develop a number of inquiry skills, in particular planning investigations and working collaboratively. They furthermore have the chance to progress their scientific reasoning capabilities and scientific literacy, through critiquing experimental design, interpreting and analysing data and graphical interpretation, and thus develop skills in forming coherent arguments.

This unit was trialled in Hungary, Ireland, UK, Turkey and Germany, with students aged 11-16 years (5 classes in total, mixed ability and gender). The teaching approach in all case studies was that of an open/guided inquiry. Inquiry skills assessed were planning investigations, and working collaboratively, as well as assessment of scientific reasoning (drawing conclusions). A broad range of assessment methods was used, ranging from in-class observation to evaluation of artefacts after the lessons, and including peer- and self-assessment.

Unit booklet

Key content / concepts

Rates of reaction
Acid and carbonate reactions
Factors influencing rates of reaction
Properties of gases

Level

Lower
Upper

Inquiry skills and competencies assessed

Planning investigations
Forming coherent arguments
Working collaboratively
Scientific reasoning
Scientific literacy

Assessment methods

Classroom dialogue
Teacher observation
Peer-assessment
Self-assessment
Worksheets
Student devised materials
Presentations
Other assessment items

The teaching and learning activities described in the Reaction rates SAILS unit were developed for the SAILS project by the team at Dublin City University (DCU). There are three activities in this unit; each activity is described, with its rationale, suggested lesson sequence and some teacher questions. Proposed methods for assessment during this unit are included, which may be used by teacher/peers to make judgements on student performance. Activity A: Designing an investigation is a preliminary activity to challenge the students with collecting and identifying a gas. Activity B: Determining reaction rate explores quantitative measurements, and graphical representation of data. This introduction to quantitative measurement leads into Activity C: Altering reaction rates, in which students identify variables that may affect measurements.

When dealing with the unit activities, it is important that the assessment is in line with the objectives of the topic and with the curriculum. It is also important that students know before they commence their work how to report their results and how they will be judged. The draft unit proposed that planning investigations was a key inquiry skill for development during implementation, but opportunities for assessment of other skills and competencies have been identified for each of the unit activities. For each of the activities, some suggested skills for assessment and criteria for success are outlined.

The Reaction rates SAILS inquiry and assessment unit is suggested for implementation with lower second level students. However, a further activity is proposed for use with upper second level students, in which the rate of reaction between sodium carbonate and citric acid is investigated and compared to that between sodium carbonate and ascorbic acid. In addition, a post-unit assessment is proposed, which can be used to evaluate students’ understanding and ability to transfer knowledge.

Below you can find the full inquiry and assessment unit for download, as well as an archive with classroom materials, including student worksheets and assessment tools for teachers to be used during the activities if available.

Unit booklet Classroom materials

Activity A: Designing an investigation

Concept focus	Production and properties of CO2 Acid-carbonate reaction
Inquiry skills focus	Planning investigations Working collaboratively
Scientific reasoning	Argumentation
Scientific literacy	Critiquing experimental design
Assessment methods	Classroom dialogue Worksheets Student devised materials

Students are asked to identify what is in the bubbles that are released when an effervescent vitamin C tablet is placed in water. The intention is that students need to design a way to trap the gas and identify it through an investigation of its properties. On completion of their investigation, students share and discuss their experimental design and results with their peers. They justify their conclusions based on the evidence that they have collected.

Activity B: Determining reaction rate

Concept focus	Acid-carbonate reaction Distinguish between reacting and dissolving Handling of gases
Inquiry skills focus	Planning investigations
Scientific reasoning	Proportional reasoning
Assessment methods	Student devised materials

Students are provided with a challenge, such as: “In the morning, I take an effervescent vitamin C tablet; however I usually have to drink it while there is still solid in the bottom of the cup. Can you measure the time it takes for the reaction to finish?” This activity can build on Activity A in that students are now familiar with handling gases and in this activity they now determine a way of measuring the rate of reaction. In Task 1 they must devise a way of measuring the rate experimentally, and in Task 2 they execute their chosen method to generate data for interpretation.

Activity C: Altering reaction rate

Concept focus	Effect of variables
Inquiry skills focus	Forming coherent arguments Working collaboratively
Scientific literacy	Presenting scientific conclusions
Assessment methods	Student devised materials Presentations

In this activity students quantitatively explore the variables affecting rates of reaction through experimentation. Students complete a final challenge investigation – “Can I speed up this reaction?” Students provide quantitative data and include graphical representations of their data. Working collaboratively is a key skill that is addressed in this activity. After this activity, students develop, explain and defend a public presentation. Through this activity it is intended to enhance their scientific literacy and scientific reasoning skills.

This unit was trialled in five countries, producing five case studies of its implementation – CS1 Hungary, CS2 Ireland, CS3 United Kingdom, CS4 Turkey, CS5 Germany. All the case studies were implemented by teachers who had some experience of teaching through inquiry, but the students involved had generally not been taught through inquiry, except for CS3 United Kingdom and CS5 Germany.

CS2 Ireland, CS3 United Kingdom, CS4 Turkey and CS5 Germany detail implementation at lower second level, with students aged 11-15 years, and students were 15-16 years old in CS1 Hungary. The students in each class were mixed ability, and mixed gender in all case studies, except CS2 Ireland, where students were all boys. In CS5 Germany, the students were participating in an elective interdisciplinary science course. Generally the case studies describe an implementation duration of approximately 90 minutes (two 40-minute lesson periods or one double lesson); CS4 Turkey describes a single 40-minute lesson.

All case studies focused on assessing students’ skill in planning investigations. Some focus as well on evaluating their scientific reasoning capabilities and skill in working collaboratively, as well as other skills. Assessment was achieved through classroom dialogue, evaluation of students’ written materials and peer- and self-assessment.

The inquiry approach used in all the case studies was that of bounded inquiry, i.e. it was guided in the sense that the teacher posed the initial question but there were open inquiry opportunities in that students had freedom in addressing the question. In CS3 United Kingdom, the teacher implemented the initial part of the activity (designing an investigation) as a purely open inquiry.

The students in all the case studies worked in groups at various stages throughout the lessons, but there was variation in both how the groups were chosen and the group size.

Within the five case studies, the inquiry skills of planning investigations, forming coherent arguments and working collaboratively were assessed in different ways. Additionally content knowledge, evidence of scientific reasoning and scientific literacy were assessed. While the case studies highlighted the development of several inquiry skills, the assessment was only described for a few of these skills. For some skills, the assessment was carried out after class and was based on a written artefact produced in class. In other situations, formative assessment guided the student learning during the class.

Below you can find the full inquiry and assessment unit for download (excluding the case studies), as well as an archive containing all the case studies.

Unit booklet Case studies

CS1 Hungary

Concept focus	Determining rate of reaction – altering rate of reaction
Activities implemented	Determining reaction rate Altering reaction rate
Inquiry skills assessed	Planning investigations Forming coherent arguments Working collaboratively
Scientific reasoning	Data entry Drawing conclusions
Scientific literacy	Presenting scientific data
Assessment methods	Classroom dialogue Teacher observation Worksheets Student devised materials
Level	Upper
Age	15-16
Prior experience with inquiry	No experience

This case study describes an after-school activity in which a cohort of students with no prior experience in inquiry or kinetics, who planned and carried out investigations using vitamin C tablets. Formative assessment was carried out at the group level, using a rubric to identify three performance levels in the skills of planning investigations, scientific reasoning, forming coherent arguments and graphical representation of data, a component of scientific literacy. Assessment methods included classroom dialogue, teacher observation and evaluation of student artefacts.

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CS2 Ireland

Concept focus	Introduction to IBSE Designing an investigation Production and properties of CO2
Activities implemented	Designing an investigation
Inquiry skills assessed	Planning investigations Working collaboratively
Scientific literacy	Critiquing experimental design
Assessment methods	Classroom dialogue Teacher observation Worksheets Student devised materials Other assessment items
Level	Lower
Age	14
Prior experience with inquiry	Some experience

In this implementation, the focus of the lesson was on collection and identification of gases. The teacher chose to assess students’ skills in planning investigations and working collaboratively, as well as their scientific literacy, as evidenced by their ability to use prior knowledge of gases in this new context, as well as their ability to critique experimental design. The skills were to be assessed formatively in two ways – evaluation of worksheets and group work placemats and teacher observation of classroom dialogue.

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CS3 United Kingdom

Concept focus	Factors influencing rates of reaction
Activities implemented	Designing an investigation Altering reaction rate
Inquiry skills assessed	Planning investigations Working collaboratively
Scientific reasoning	Trouble-shooting
Scientific literacy	Critiquing experimental design
Assessment methods	Classroom dialogue Teacher observation Self-assessment Student devised materials
Level	Lower
Age	11-12
Prior experience with inquiry	Some experience

Two activities from the Reaction rates SAILS inquiry and assessment unit were implemented in two lesson periods. Students’ skills in planning investigations and working collaboratively were assessed formatively through in-class observation, evaluation of students’ written work and a student survey on teamwork. Scientific reasoning and scientific literacy were also evaluated, looking at students’ ability to critique experimental design, identify potential problems in experimental plan and critical thinking.

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CS4 Turkey

Concept focus	Methods for collection of gases
Activities implemented	Designing an investigation
Inquiry skills assessed	Planning investigations Forming coherent arguments
Assessment methods	Classroom dialogue Student devised materials
Level	Lower
Age	12-13
Prior experience with inquiry	No experience

In this case study, the teacher evaluated student skills at the group level, focusing on planning investigations and forming coherent arguments. The teacher did not explicitly assess students’ inquiry skills during the activity and instead focused on providing guidance and trouble-shooting where required. However, formative assessment was provided during the inquiry activity through question and answer sessions. The teacher also assessed the written student artefacts after the lesson.

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CS5 Germany

Concept focus	Determining rate of reaction – altering rate of reaction Handling and identifying gases
Activities implemented	Designing an investigation Determining reaction rate Altering reaction rate
Inquiry skills assessed	Planning investigations
Scientific reasoning	Identifying variables
Assessment methods	Classroom dialogue Teacher observation Peer-assessment Student devised materials Presentations
Level	Lower
Age	14-15
Prior experience with inquiry	Some experience

Students’ skills in planning investigations and their ability to define and control variables were assessed formatively during this implementation. Assessment was achieved through a combination of teacher observation, evaluation of students’ written protocols and peer-assessment of posters outlining experimental plans.

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Reaction rates

Why wait for my vitamin C tablet to dissolve – how can I save time?