Refraction Lab
1. Fill Dish ½ full of water
2. Place dish on circular graph paper. Be sure the dish exactly matches up with the
template already indicated on the graph paper.
3. Draw a normal to the flat side of the dish that continues through both sides of the
dish but does not extend out of the far side of the dish.
4. Shine laser into the center of the flat side. Be sure laser is parallel to table top
5. Make 3 points. One at the center of the laser pen where the laser comes out,
one at the center of the dish and one at the point the laser comes out of the
dish (be sure to actually look at the BACK of the dish to locate the third
point). Connect the 3 dots with a certain color pen. Draw arrow heads to indicated
the path of the light both in and out of the water. (Can you see the path of the laser
in the water?)
6. Be sure laser is pointed EXACTLY at the center of the dish where the normal line
enters the flat side and DO NOT continue your lines out the back of the dish!!!!
7.
You have now established 2 lines. A line representing the path of the laser while it
is in the air and another representing the path of the laser while it is in the
water. Repeat steps 4-6 five more times at five different angles with five
different colored pens. Also make sure all initial data is recorded in and area from
00 to 900.
If you have any questions about this procedure refer to figure 23-2 on the screen.
Analysis
1. Measure and record the i (air)and refracted (water)for all six trials. Be sure to use
the normal line as 00. (You do not need a protractor for this)
2. Record all data into Data Table 23-2.
3. Use Snell’s Law to calculate the actual values of your refracted angles.
4. Calculate the % error for all colored rays and record your data in Data Table 23-3.
Questions
What is an easier word to say than “refracted”?
Could you see the laser as it traveled trough the air? The water? Explain.
What relationship do you see between the incident and refracted angles?
When light travels from a less dense substance into a more dense substance, does
the light bend toward or away from the normal line?
5. What inference can you make about the difference between the 2 angles?
6. What happens if light starts in the water and comes out to the air (Note: Do not
try this! Do not place laser pen in the water!) That is to say what would
happen if you reversed the arrow heads on your lines?
7. What would happen if the laser entered in along the normal line? Use the
“Lawnmower moving into the grass” analogy to help you explain.
8. Did there seem to be a relationship between incident angle values and % error?
1.
2.
3.
4.