ONLINE PHYSICAL SCIENCE Name: .
At-Home Lab Activity
”Measurements”
Overview:
A physical quantity is a property of an object that can be measured with a measuring instrument. Examples include length, width, time, mass, etc. A physical quantity also has units (such as feet for length).
Physical quantities can be divided into two types:
1. Fundamental quantities - Mass, length and time are the most fundamental physical quantities.
2. Derived quantities - Derived quantities are just quantities that are derived from one or more fundamental quantities. For example, area is derived from the basic quantity length (area = length2).
Objectives:
In this activity you will:
· Measure fundamental physical quantities
· Measure derived physical quantities such as area and volume
· Perform unit conversions
Equipment Needed:
You will need a measuring tape (with inches and centimeters scale), bathroom scale, kitchen timer or stop watch (or mobile phone app), and measuring cup (with mL scale).
Procedure:
Length Measurements:
1. Measure and record your height in centimeters (cm) and in inches (in) using the measuring tape.
Photo 1: Take a photo of this process.
Height = ? cm Height = ? in example: Height = 165.1 cm (measure to nearest tenth)
2. The conversion factor for inches to centimeters is 1 inch = 2.54 cm. Find this conversion factor using your measurements. Hint: Divide your height in cm by height in inches.
Your conversion factor: 1 inch = ? cm
3. Calculate the percent error between the conversion factor from your measurements and the actual conversion factor of 2.54. To calculate percent error do this calculation:
Percent Error = [2.54 cm - Your conversion factor from #2] ¸ 2.54
Be sure to take the absolute value and multiply by 100 to make it a percentage
Your Percent Error = ? %
4. If you made no errors in your measurements, what Percentage Error would you have gotten?
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5. What are some reasons (or sources of error) that leads to your calculated Percent Error?
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6. Calculate and record your height in feet
Your height in feet = ? ft
Explain how you got your answer:
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Mass Measurements:
7. Using a bathroom scale measure and record your weight (or that of a friend) in pounds (lbs). Photo 2: Take a photo of this process.
Weight = ? lbs
8. Convert your weight to kilograms (kg) and Newtons (N).
Hint: 1 lb = 4.5 N and 1 kg = 2.2 lbs
Weight = ? kg Weight = ? N
Time Measurements:
9. Measure a height of 1 meter above the ground using a measuring tape. Hold your pen at that height and, using your stopwatch, measure the time it takes for your pen to drop to the ground. Try to minimize any errors due to your reaction time in judging when the pen begins to drop and when it hits the ground. Do this 3 times recording each time, then calculate the average time to drop.
1st Time = ? s 2nd Time = ? s 3rd Time = ? s Average Time = ? s
10. Now calculate what the theoretical time of fall should be for 1 meter using the formula: time = square root (2h/g) where h = 1 meter and g = 9.8 m/s2.
Theoretical Time = ? s
11. Find the percent difference in this Theoretical Time and your Average Time using the following equation:
Percent Difference = (Difference in Times ¸ Theoretical Time) x 100% (Take absolute value if negative)
Percent Difference = ? %
Explain why there is a difference:
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Area Measurements:
Next you will find the total floor area of your house or apartment. You will compare this to the actual floor area, so you will need to locate a floor plan of your residence with this information (or estimate).
12. Measure the length and width (in feet) of each room using the measuring tape. Find the area of each room (length x width) and add them together to get the total floor area in square feet. For rooms that are not perfectly rectangular shaped you will need to break the area into smaller blocks that you can measure individually.
Total Floor Area = ? ft2
Explain how you got this value. Include a few of your calculations:
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13. What is the actual area according to your floor plans?
Actual Floor Area = ? ft2
14. Find the percent difference between your measured total floor area and actual floor area.
Percent Difference = ? %
Explain how you calculated this percent difference:
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Volume Measurements:
15. Measure the height and diameter in centimeters of a coffee cup using your measuring tape.
Height = ? cm Diameter = ? cm
16. Calculate the volume of the coffee cup using the equation V = pR2H, where R = half the measured diameter, and H = measured height:
Coffee Cup Volume = ? cm3
17. Now fill the coffee cup with water. Transfer the water to a measuring cup without spilling any. Read and record the volume in milliliters (mL) from the side scale of the measuring cup. Photo 3: Take a photo of the coffee cup and the measuring cup with water.
Measuring Cup Volume = ? mL
18. Find the percent difference between your coffee cup volume and measuring cup volume.
Percent Difference = ? %
Explain how you calculated this percent difference:
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Why are these volumes different, shouldn’t they be the same? List specific measurement errors you may have made that led to this volume difference:
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Paste in your lab photos below:
Photo 1: Take a photo of your height measurements
Photo 2: Take a photo of your weight measurements
Photo 3: Take a photo of your coffee cup and measuring cup with water in it.