Optics+Lab

= = = Optics Lab = = = **2010-2011**

__**Titles of each section**__
Should Include: Title Name Partners Names Class Period

**Use the purpose stated below:** Purpose: The purpose of this lab is to compare the relationship among object size, image size, object distance, image distance, and focal length for a convex lens.


 * // __Note:__ Refer back to this purpose in your conclusions. //**

Use the procedure provided below, and include a simple, labeled sketch of the lab set-up.
 * Due Date for sketch only: April 1 & 4 @ start of class **

Sketch criteria: · Final copy format: neatly with a ruler, pencil, on the computer or with colored pencils. · Includes: title, labels for variables (object distance, etc), all materials needed, key

__Suggested Procedure -__ You will need to modify this procedure to improve accuracy.


 * 1) Assemble the apparatus as shown.
 * 2) Light candle, and after about 20 seconds, measure the height of the flame (//object size//). Record in data table.
 * 3) Place the candle about 15 cm from the lens (//object distance//). Record in data table.
 * 4) Move screen until the image of the candle is focused on the screen.
 * 5) Measure the height of the image of the flame (//image size//) Record in data table.
 * 6) Measure the distance between the lens and the screen (//image distance//). Record in data table.
 * 7) Repeat steps 2-6 for the following object distances: 20cm, 25cm, 30 cm, 35 cm, and 40cm. Record all data in table.
 * 8) For any two of the object distances, create a ray diagram to show where the image would be located and how large it would be.

**Data Table (20 Points) __Due Date:__** April 1 & 4 @ end of class
**All data should be in final draft form using a spreadsheet in Google Docs! Call the spreadsheet "Lastname.Opticsdata"** __ Note: Make sure that all data tables/spreadsheets are in final draft form. Don’t forget to title data tables, include units and round numbers. __ __ //Include the following headings with proper units:// __
 * Object Distance
 * Object Size
 * Image Distance
 * Image Size
 * Ratio of Image distance to Object distance (//use a formula//) [[image:Di_Do.png width="27" height="45"]]
 * Ratio of Image size to Object Size (//use a formula)// [[image:Si_So.png width="24" height="45"]]
 * % Difference[[image:Percent_Diff.png width="165" height="75"]]
 * Theoretical Focal Length for lens
 * Experimental Focal Length [[image:Focal_length.png width="103" height="54"]]
 * Percent error (Compare experimental focal length to the theoretical focal length) [[image:percent_error.png width="189" height="51"]]

//Note: __List all measurements in the correct amount of precision and round the calculations to 2 decimal places as appropriate__//__. //Make sure to title data tables and try to get them all on one page.//__

**Ray Diagrams (20 Points) __Due Date:__** April 5 & 6 @ end of class
__ Using the theoretical focal length, for any two__ __experimental trials, create ray diagrams (by hand or using computer) to show where the image would be located and how large it would be.__


 * Make sure that your diagrams:**
 * Are your own not copied from computer or book.
 * Are neat and clearly labeled
 * Are appropriately color coded or colored (no pen)
 * Include a scale
 * Include a key or legend


 * Honors Challenge (15 Points):** __You will need an additional ray diagram to help analyze the relationships between the variables here.__

    Using an additional ray diagram as evidence, provide a comprehensive explanation for the relationships between the variables in the lens equations. For example, superimpose additional object rays to show an increase or decrease in object size and increase or decrease in object distance. Use this to explain the effects on image size and distance.

Using theoretical focal length, object distance, and object size as knowns, for any two of your trials (the same ones for which you made ray diagrams):

 * Calculate image distance, [[image:Di.png width="102" height="52"]]
 * Calculate image size, [[image:Si.png width="81" height="45"]]

The ratio between Di/Do should be equal to the ratio between Si/So
__ **In addition for one trial:** __
 * Calculate experimental focal length
 * Calculate percent error for focal length

//NOTE: __Show formulas, substitutions, and units__//
**Optional: Use Open Office Formulas or Math Type for this calculation work**

//Refer to data, diagrams and observations! Use appropriate rules of scientific writing. No more than 2 pages (double-spaced) total.//


 * Results: What were your results? (10 pts)
 * Report your experimental results and your calculations and how they compare for the two trials of your choice.
 * What did you determine for the average experimental focal length and percent error of your lens?
 * Analysis: Explain what your data shows. (25 pts)
 * What happened to Di when Do increased? Use data and ray diagrams to support your answer. Explain what happens to light in the lens to create that effect. (Use the online Optical lab bench to learn the explanation.)
 * What happens to Si if So increased and Do was constant? Describe how the light behaves in the lens to explain that effect.
 * Does the data support the predicted relationships as given in the lens equations? What data supports this claim?
 * Describe at least three of your sources of error, how they affected the results and how they could be reduced. //Don’t just discuss human error!// <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> (10 pts)
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; font-style: normal; font-weight: normal; list-style-type: disc; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Conclusion (5 pts)
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; font-style: normal; font-weight: normal; list-style-type: circle; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Conclusion sentence that sums up purpose and results
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; font-style: normal; font-weight: normal; list-style-type: circle; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Answers the question, “Did your data verify the predictions?”
 * <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 11pt; font-style: normal; font-weight: normal; list-style-type: circle; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Answers the question, “Did your data verify the predictions?”

__IMPORTANT THINGS TO REMEMBER!__

 * Each section begins with a topic sentence, and is followed by supporting details and actual examples from the data you collected.
 * You should include diagrams to back up statements and theories in the essay portion of the report.
 * Include a bibliography in MLA format for any resources that you use, including the textbook.
 * Before passing in lab check that you have all pieces by going through the product descriptor and comparing it to your lab.