11.2Refraction and Reflection Lab

Today’s Goals§ Today we will be working with two different media:

§ Plexiglass§ Water

§ By the end of today’s activity you will accomplish the following:§ Observe Refraction and Reflection in Plexiglass and water§ Determine the Critical Angle§ Observe Total Internal Reflection

EACH GROUP must hand in their both charts, marked polar paper with exact degrees, & questions

DUE: WED.APR.20/16

Recall§ Critical Angle

§ the angle of incidence that produces an angle of refraction of 90�

§ At this angle of incidence, the refracted ray lies along the boundary between water and air

Recall§ Total Internal Reflection

§ when incident light is not refracted but is entirely reflected back from the boundary

Recall

Materials

§ Ray box (use a single ray)§ Plexi glass§ Water container§ Polar paper§ Pencil§ Eraser§ Laptop to verify angle

§ (use class website – under “labs”)

Step 1: Determining the Critical Angle of Plexiglass

Polar Paper

Polar Paper

Ray Box

Polar PaperMark a dot & label it i=“30o”

Polar Paper

Ray Box

Determining the Critical Angle§ Increase the angle of incidence by increments of 5 degrees§ Record the angle of reflection (r) and refraction (R) § When the angle of incidence results in a refracted ray that

is close to the flat edge of the semicircle, increase the angle of incidence by increments of 1 degree

§ If you observe Total Internal Reflection go back and redo the last five degrees until you are able to determine the exact value of the Critical Angle

§ Fill in the rest of the table

Step 2: Determining the Critical Angle of Water§ Fill in the semicircular dish with water (do not overfill) § Follow the same steps with the water container

Step 3: Inquiry: What is Snell’s Law?

§ Complete the last column for both plexiglass and water

sin isin R

* Remember to round to the nearest whole number

Step 4: Answer the concluding questions

§ Make sure you answer in complete sentences – proper grammar, spelling etc.

§ For question #6 – look up Snell’s Law on a legitimate website on the internet.§ If you finish in time, you may use your phone to

research this law.

Step 5: Hand in your lab

§ Your lab write-up is due at the beginning of next class!