Framework Chemistry 10 An Inquiry Based Science Teaching and Learning Framework

Topic/Learning Activity

Separate mixtures using a variety of techniques OC2 Student Cohort Student Level First Year - Mixed ability

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Prior Knowledge States of matter and changes in state

Stimulus to Engage How do you get the students interested in the topic to start? ‘Sabotage on the international space station’ Activity 1 – A work sheet compiled by Sarah Gavigan, Colaiste Lorcain and available on the Discover Sensors Forum, Autumn 2010, Kildare VEC Schools. http://www.discoversensors.ie/forum/topic/sep-mixtures-worksheet This resource helped to develop the principles of filtration and evaporation. To explore distillation and chromatography, the discovery of a note on the space ship indicating that the drinking water had also been contaminated opened a discussion on how to purify the water and how to determine which astronaut on the space station wrote the note and is the saboteur.

Science Questions Initial questions leading to the questions students will work on during the activity: ■■

Can you find a way to separate the iron, and sand from the food that has been contaminated?

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The liquid that has contaminated the water has a boiling point of 78oC. Based on the information that you have, explain how you might purify the water.

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If each member of the crew is issued with their own personal marker pen, how can the note, written by the saboteur, be used to determine the guilty crew member?

Leading to questions that you want the students to investigate ■■

What is common to all the material that has rusted?

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What conditions are necessary for rust to occur?

Learning Outcomes Content Knowledge At the end of this activity students will be able to ■■

Define Filtration, Evaporation, Distillation and Paper Chromatography

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Distinguish between the terms Soluble and Insoluble, Solvent and Solute

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Understand the difference between filtrate and residue

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Explain what a mixture is

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Recognise the composition of a mixture can change

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Distinguish between evaporation and condensation

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Explain the role energy plays in changes of state

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Framework Chemistry 10 An Inquiry Based Science Teaching and Learning Framework

Process At the end of this activity students will be able to

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Predict the outcome of the investigation

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Design, prepare and set up an investigation to complete the task

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Select and use a variety of equipment in the process

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Separate the required components

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Record data

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Compare results with prediction

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Redesign investigation if necessary

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Analyse Results

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Compare results to rest of class groups

Skills At the end of this activity students will be able to ■■

Work as members of a team

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Recognise what worked well and what needs improvement

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Analyse data and form a conclusion from evidence obtained

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Revise their prediction if required

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Recognise, discuss and decide on improvements that could be made

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Write up an investigation on each of the processes to include materials used, procedure carried out, results, diagrams, analysis and conclusions reached

Questions during Activity Questions to drive student learning (directing them to the learning outcomes): ■■

If you were stranded on a desert island, do you have any idea how you could get fresh water from salt water?

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How could you make sure there was no sand in the water?

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What materials could you use if you didn’t have any scientific apparatus?

http://www.discoversensors.ie/forum/topic/sep-mixtures-worksheet Questions relating to worksheet ■■

Where does ‘Sustenance X’ go when water is added?

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If more ‘Sustenance X ‘was added would it continue to disappear?

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Both sand and ‘Sustenance X’ are solids. From the information you have been given in the worksheet how would plan the separation of the two solids

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Explain what a mixture is?

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What safety issues do you need to consider in this investigation?

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How could you speed up the process of evaporation?

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What precautions would you advise other students to take when carrying out this process?

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How would you plan an investigation to separate dyes from marker ink?

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Framework Chemistry 10 An Inquiry Based Science Teaching and Learning Framework

Questions to probe understanding: Filtration ■■

Give an example of a mixture containing a solid that dissolves in water and one that contains a solid that does not dissolve in water?

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List three materials that could be used to separate sand and water

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Predict which material will be the most effective

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What evidence can you use to support your decision

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Evaporation ■■

What process would you use to separate ‘Sustenance X’ from water?

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Explain what happens in terms of energy during evaporation?

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From your investigation what do you think are the two most important factors to consider when evaporating a liquid from a solution?

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At what temperature does evaporation occur?

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Explain what happens when the water in a puddle disappears

Chromatography ■■

What solvent could you use to separate the ink dyes in a marker?

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Why did you decide on this solvent

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Explain how the dyes in the ink are separated

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Apart from separating the dyes in marker ink, list 2 other substances that could be separated in this way

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Change the brand of the marker but not the colour of the marker and carry out the investigation. What can you conclude?

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List 2 factors that you as a team feel would influence the separation process and explain the reasons for your choice

Questions to get students thinking about their own learning (metacognition): ■■

What two factors do you see as being the most important for successfully separating the substances

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How would you purify muddy water?

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How could you separate a soluble solid from water and produce a sample of the solid and the water at the end of the process?

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What is the difference between each of the separation processes?

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Evaporation occurs at 100oC. Discuss this statement

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Where does evaporation occur in nature?

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What changes would you need to make to the chromatography process when using a permanent ink marker?

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Describe the energy changes that occur during evaporation and condensation

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All solvents behave in the same way. Discuss

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Why do dyes travel different distances up the paper?

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If the length of the chromatography paper was increased or decreased, would this have any affect on the separation of the dyes?

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Framework Chemistry 10 An Inquiry Based Science Teaching and Learning Framework

Developing the Activity How do you stimulate students to ask even more questions/think further? Chromatography ■■

The story continues further...

The saboteur on the space ship wrote a note in which he/she threatens to contaminate the drinking water with a colourless toxic liquid that would affect the balance of the crew of the space ship. This note is in the possession of the captain.

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A crew member has written this note. How would you investigate and collect evidence to determine which member of the crew is responsible for writing this note? ■■

Use of a waterproof pen in chromatography with water as a solvent.

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Why does separation not occur?

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What changes could you make to ensure separation occurs?

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Using a selection of coloured markers, how would you determine if there are pigments that are common to a variety of markers?

Possible supporting activities: Filtration ■■

Design an investigation to determine the effectiveness of several different household materials in the filtration process (i) Design a water filtration system that could be used to change muddy water into clear water

Evaporation (ii) Design a low cost desalination system to provide water from salt water

Questions for supporting activities: ■■

Explain how you decided on the materials to use in the investigation

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Rank the materials used in the filtration model in order of effectiveness

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How did you measure the effectiveness of the materials used in the filtration model?

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Draw a diagram of your desalination system

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What improvements could be made to your design?

Reflecting Back to Learning Outcomes How many of your intended outcomes were achieved? All learning outcomes achieved apart from those related to the process of distillation due to constraints of time Do any of your intended outcomes need to be revised?

Additional Resources Stimulus materials, websites, etc.: Additional resources for homework activities were sourced from http://www.discoversensors.ie/forum/topic/pdfs-for-separation-questions

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Framework Chemistry 10 An Inquiry Based Science Teaching and Learning Framework

How has the use of ICT enhanced the learning? Evidence of enhancement The material uploaded to the Discover Sensor website by other teachers provided the stimulus for engagement in the topic. The theme of food and water being contaminated by a saboteur on board a space ship provided all the material needed to develop the different separating process The added benefit of worksheets also available on this same website, created by fellow science teachers acted as a means to evaluate the learning process in a fun way

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Additional Comments The end product - Sustenance X (Salt) separated from the sand and the iron filings

IRON

SAND

‘SUSTENANCE X’

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