Achievement Task

Canadian Fluids is the country’s main producer of clear, colourless liquids. A high level of quality control has been important to the maintenance and growth of their company. Canadian Fluids Inc. wants to develop an easy system for determining the identity and density of the various solutions used in its manufacturing process. An easy identification process would save them money and help them to produce a better product for their customers. Canadian Fluids hopes to exploit differences in the refractive index of the various solutions in order to provide a quick determination of the liquid's identity and density.

Your engineering company has been hired by Canadian Fluids to investigate the science of refraction. They would like two questions answered.

1. Does the concentration of a solution affect the index of refraction?
2. Does the type of solute or the type of liquid affect the index of refraction?

Your team is to choose one of these questions to investigate. You are to determine if a relationship exist between the dependent variable (index of refraction) and the independent variable that you choose. Ultimately you are to suggest a protocol that will allow Canadian Fluids to identify a solution by its refractive index.

Part A: Research

Before you begin your investigation you should seek answers to the following:

1. What is the index of refraction? What values do you have to measure in order to calculate the index of refraction for a substance?

2. Any liquid you are working with will need to be held in some form of container. How can you prevent the container from refracting the light you are passing through the container? (ex. type of material, shape of container, angle of incidence)

3. A very accurate method to determine the index of refraction involves the use of a device called a refractometer. You should gain an understanding of how this device works. Go to www.pearsoned.ca/physics11 to begin your investigation.

4. Other scientists may have already published some research in this area. Search the Internet for any lab procedures or articles that are applicable to the task that you are being asked to complete.

5. How will the light source you choose to use affect your determination of the index of refraction? How will the temperature of the media affect your values for the index of refraction?

Part B: Testing and Inquiry

1. Your team needs to determine a procedure that will allow you to identify the concentration or type of solution by measuring the index of refraction.

2. You may want to begin your work with a media with a known refractive index. Water, for example, has a refractive index of 1.3330 at 20° C. By comparing with a known value you can determine the accuracy of your procedure before proceeding with any new substances.

3. Make reference to page 395 in the Pearson Physics 11 text if you are unsure of how to measure the index of refraction. Polar coordinate paper, a ray box, and a semicircular dish are typical materials you may need to use to complete your investigations.

Part C: Analyze and Reflect

1. Without the use of a refractometer, the degree of accuracy that you will achieve will not be as great as the published values for the index of refraction. Before you proceed too far, make some attempt to determine the precision of your equipment and how it will affect your calculations.

2. What criteria will you use to determine if your procedure was successful? You may want to consider some of the following: Are your results reproducible? Was the difference in refractive index values significant enough to allow your equipment to identify the substances? What errors may have been caused by your choice of equipment?

3. Was your procedure successful? Justify the success or failure of your experiments. Be sure to make reference to the task you were given.

Part D: Communicate

Canadian Fluids has requested that you report your findings in a formal report which will be discussed at their next Board meeting. Your report should include:

1. An introduction that briefly explains the relevant theory involved in your experimentation.

2. A description of the your procedure (written in the past passive).

3. A summary of the data that you collected.

4. An analysis that explains your results and comments on their reliability. Include a description of the sources of error and make suggestions on how you would remove these errors. Discuss any applications or extensions that you see for your work.

5. Conclude your report with a written protocol that Canadian Fluids personnel could use to identify the liquids that they manufacture.