PHO 101 Photonics Concepts
Three Rivers Community College ONLINE
Home Lab #4
Before you begin this lab, you should read the tutorials on Measurements. These are located in the TUTORIALS folder, located on the course home page.
Purpose: Although this is not an optics lab, it will require basic skills and procedures that are common to the labs you will do in the rest of the course. You will be taking measurements with a metric ruler, and doing calculations, paying attention to significant digits and precision. The first part is definitely something you did in elementary school, but the second is of great importance when you are stating results, so that you don't imply a greater accuracy than your results deserve.
This will be a group lab- you will be sharing data with everyone in the course. For this reason, please don't leave the lab until the last minute- you will hold everyone else up. It's fine to share your results too- you should all have similar results.
Materials:
Figure 1 How to cut the paper into eight pieces
Procedure:
1. Choose one of the paper rectangles for this exercise. Recycle the other seven, or give them to a classmate!
2. Measure the length and width of each piece of paper to the precision of the smallest unit on your ruler and record in the data table. (If your ruler has mm markings as the smallest unit, you would state your answer to the nearest mm.)
3. NOW- very important: Post your four length and width measurements on the course discussion site. There will be a special thread for this, called "measurement lab data". To complete this lab you need rectangles from at least six (and up to 10) rectangles. You may choose from the posted class data the rectangles you wish to use. Once you have the length and width measurements:
4. Calculate the perimeter of each rectangle (P = 2L + 2W) and record to the correct precision. (nearest mm)
5. Calculate the area of each rectangle (A=Length times Width) and record to the correct accuracy. (How many signficant digits?)
6. Calculate the average of the perimeters found for the four rectangles and state to the correct precision.
7. Calculate the average of the areas for the four rectangles and state to the correct precision.
Report
You should turn in
1. a table similar to that shown in Table 1, with the length and width data you used and the results entered.2. a sample calculation for perimeter and for area.
3. answers to the questions below in complete sentences
Sample Length Width Perimeter Area
Average Perimeter___________________________
Average Area_______________________________
Questions:
1. What is the precision of the length measurement?
2. What is the precision of the width measurement?
3. How many significant digits are there in the length measurements?
4. How many significant digits are there in the width measurements?
5. How many significant digits are there in the calculated area?