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The GeoGebra applet has a spreadsheet that contains data for the intensity of light at 6 different distances. You can use this data as a starting point for building a model.

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Bob's GeoGebra Work with My (Tom) New Idea

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Bob's GeoGebra Work with My (Tom) New Idea

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This is my work with functions of the form y=K/x. Is there a way this function can be improved?

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Tom's GeoGebra Applet with function y=K/x

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Here is my GeoGebra applet with a parabola that is close to going through the points. Can anyone make it better?

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I used the data in the spreadsheet to plot points and then tried to get a parabola to pass through the points. I can hit some of the points, but not all. See if you can improve this.

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Here is GeoGebra as I left it with my parabola passing through two points.

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I don't think a parabola is going to work, so I have tried a different function like y=K/x. I can get a curve that looks like a closer fit than the parabolas used by Mary and Bob, but it is still not perfect and misses some points.

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I like Bob's idea of a parabola so I played around with quadratic functions and got a bit better fit. I got a curve that is close to going through the points, but it is not a perfect fit

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This video explains the problem situation

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When a person holding a flashlight walks towards us the light gets brighter. We are going to investigate this situation and build a mathematical (function) model for the changing light intensity.

In the two boxes immediately below you will find a video explaining the modelling task and a GeoGebra applet that will get you started by providing initial data in a spreadsheet. Click on the links to get the video and applet.

When you have some ideas on how to start the problem and have tried them out in GeoGebra, create a Jing video showing your actions and the thinking behind them. Post a note below that links to your Jing video and post a second note that links to your GeoGebra sketch as you have left it.

If some people have already worked on the problem look at what they have done by viewing their videos and visit their linked GeoGebra sketches. When you see a place where you can contribute to the solution begin your work with the previous GeoGebra sketch. Create a Jing video showing your work in GeoGebra and explaining your thinking. Post notes that link to your video and your revised GeoGebra sketch.

Together your group can build a model for the light intensity as the distance changes.