Lab Activity: Measurement

Goal: To gain experience making measurements and calculations using the ideas associated with significant figures.

Type of Activity: Structured Inquiry

Materials Needed: A 12 inch ruler and a tape measure marked in centimeters

Activity:
1. Find an area of a non-carpeted floor that is at least six feet wide and six feet long. Mark off the area in some way. Perhaps place one corner of four books or pieces of wood at the corners of the area as you can see in the top view of the floor in the sketch below.

2. Being careful not to move the books once they in place, measure the width and the length of the area using a 12 inch ruler. Since the ruler will not span the width or length, you need to carefully move the ruler along the floor using your fingertip to mark where the end extends to prior to each move. Record your measurements (in inches) in the data table. Use the concept of significant figures to round off your measurements appropriately.
3. Again, without moving the books, use the tape measure to find the width and the length in centimeters. Record your measurements in the data table again rounding off appropriately.
4. Calculate the area of the space using the measurments from step 2. Round off your calculation using the rules of significant figures. Record your answer for later use but do not include it in the data table.
5. Calculate the area of the space using the measurments from step 3. Round off your calculation using the rules of significant figures. Record your answer in the data table using square centimeters as the unit.
6. Convert the area you found in step 4 with this conversuion factor: 1.00 inch = 2.54 cm. Record your answer in the data table.
7. Calculate the percent difference between the area calculations from steps 5 and 6. Please show these calculations and all others made in this lab in the analysis section of your lab report.
8. In the conclusion of your lab report, comment on which measuring device you think gave the more accurate answer. Be specific as to the reasons. They should include physically reasonable sources of error apart from simple "human error." 

Data Table