Overheard: all the starwheel questions

2013-01-23_19-39-28_490
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(Overheard after students practice all three possible types of starwheel (planisphere) questions in class.)

Instructor: "Hey, uh--do you know what Rage Comics are?" (Beat.) "But of course you do, you're college students." (Draws in Rage Comics' "All of the Things" character next to outline of possible starwheel questions.)

Picto-quiz: lenses and images

Let's apply the concepts introduced in a previous presentation, where we used ray tracings to find images produced by converging and diverging lenses.

Pair up in groups of two or three, pick up a whiteboard, and for each of these real-world examples, decide whether this is a converging or diverging lens, producing a real or virtual image, and choose the corresponding ray tracing diagram (or diagrams) from your worksheet.

For this image produced by a water glass, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image produced by a camera lens attachment, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image produced by magnifying glass, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image produced by a pair of glasses, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image on a frosted glass screen produced by a lens on an optical bench, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image produced by a door peephole, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image produced by a glass paperweight, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

For this image produced by a slide projector, is this produced by a converging or diverging lens? Is this a real or virtual image? Which ray tracing(s) ((1)-(10)) best match(es) this?

How do you know this?

Kudos: terrible at science

"Terrible at Science" by Student 1206
Astronomy 210
December 2012
Cuesta College, San Luis Obispo, CA

Kudos: wonderful facial hair

"Wonderful Facial Hair" by Student 2580
Physics 205A
December 2012
Cuesta College, San Luis Obispo, CA