Measurement and Uncertainty Lab Manual

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Jan 9, 2024

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Measurement and Uncertainty Lab Manual Resources: https://www.youtube.com/watch?app=desktop&v=-zuIftmI-6I https://www.youtube.com/watch?v=H3vYS6cBtpQ https://www.youtube.com/watch?v=ae4NMm763mM Overview In this investigation, students will use basic scientific measuring equipment to determine the accuracy and uncertainty associated with measurements using common laboratory glassware. Time Requirements Needed but not supplied: • Permanent marker Overview Video: Measurement and Uncertainty Outcomes • Determine the uncertainty of measurements with standard glassware and equipment. • Determine the accuracy of measurements with standard glassware. Why Should I Care Communication is paramount in the scientific community because reproducibility is what establishes the theories and laws we recognize within the various scientific disciplines. If presented theories cannot be reproduced by scientists across the globe, they will not be confirmed. And scientists cannot reproduce an experiment if the conditions, procedures, and results are not clearly communicated via terminology every scientist understands. The General Conference on Weights and Measures began creating a common language among scientists when they defined the International System of Units, abbreviated SI (from the French Le Systeme International d'Unites). You can consider the SI system as the modern form of the metric system. The SI system is the only system of measurement that is officially recognized in nearly every country in the world.

When reporting measurements, significant figures complement the SI units by allowing scientists to recognize how precise a reported answer is, or how much uncertainty there is within reported results. This also allows scientists to immediately gauge whether their equipment is capable of accurately reproducing the reported values of an experiment. Background Measurements can come in many forms, such as length, weight (mass), volume and temperature, but there are many other forms you may encounter in the future. This investigation will focus on two: how to measure weight and volume, and some common equipment used to measure both. Using Your Scale To measure the weight of an object (more scientifically referred to as the mass) a scale or balance is used. Your lab kit contains a small scale that will be used to weigh all substances in your course. Within the box your scale arrives in are two AAA batteries and the balance with a lid. When you remove the lid, there are complete instructions on the use of the scale on the inside. When looking at the top of the scale, there are 5 points of interest. First is the pan, this is the large, flat surface above the LCD screen. Objects you wish to weigh are placed on the pan. Below the pan is the LCD screen. This is where the mass of an object on the pan will be displayed. Below the screen are three buttons reading, from left to right, ON/OFF, MODE, and TARE. When you first turn on the balance by pressing the ON/OFF button the screen should read 0.00 g (g stands for grams in this instance). This indicates there is no mass on the balance. If the letter at the end is not g, you can press the MODE button until “g” is listed as the units. If the screen is not indicating a mass of 0.00, you can press the TARE button to re-zero the scale. After you press the TARE button, the scale should reset to 0.00 g. The scale has a maximum capacity of 100 g; if a mass greater than 100 g is placed on the pan, the screen will read “0_Ld,” indicating too large a mass has been placed on the pan. Measuring Liquids To measure a volume of liquid, typically a piece of glassware, such as a beaker or graduated cylinder, is used. The equipment is placed on a flat countertop or table, and liquid is poured into it. The bottom of the meniscus (the concave layer or water at the top) is where the volume is measured against the scale (Figure 1). As you will see in Activity 2, the volume you read from a particular piece of glassware may be at best an estimate. Having measurable results is an integral part of the scientific method. Scientists must contend with two main factors while taking measurements: the accuracy of the measurement and the precision of the measurement. Accuracy is how close a set of data is to the actual value. 'Accuracy is gauged by comparing the measured value of a known standard to its true value'.Ignore color of text. Precision refers to how close a data point is to other measurements in a data set Measuring Liquids (cont... ) A data set that is accurate is not necessarily precise, whereas a very precise data set could be highly inaccurate. Forces that affect the accuracy and precision in measurements are error. In scientific settings, error is defined as the difference between the measured value and the actual value, where the actual value is a known value, sometimes referred to as a standard. Two main types of error exist: systematic and random. Systematic error is a type of error that causes measurements to be inaccurate by a certain value in a particular direction. Systematic error can be further divided into absolute and relative error. Absolute error has both magnitude and direction and is represented as a discrete value. For example, if your alarm clock is slow by five minutes it has a systematic, absolute error. Each morning you will be getting up five minutes later than planned and dealing with the potential repercussions. Absolute error can be calculated as follows:

absolute error = |measurement - actual value| absolute error = |6:35 - 6:40| = 5 minutes The || brackets indicate that you take the absolute value of a calculation. An absolute value means the value in the bracket will always be positive. There is a second type of systematic error called relative error , or percent error, which is expressed as a percentage. One of the more common measuring devices with built-in percent error is the speedometer of a car. Most automobile manufacturers have a tolerance of ±2% in their speedometers. Measuring Liquids (cont... ) This means that any given speedometer could read between 2% too slow or 2% too fast. If your speedometer reads 61 mph, while actually traveling 60 mph, the percent error is calculated using the equation below. relative error = ((|measurement - actual value| / actual value )) x 100% relative error = ((|61 mph - 60 mph|/ 60 mph)) x 100% = 1.6% Related to relative error is the concept of percent error. Percent error is calculated by comparing a measurement against an accepted value. Typically an accepted value is measured with a high level of precision and accuracy, but it is still a measured value—no matter what, there is always some form of error associated with a measured value. percent error = ((|measurement - accepted value|/ accepted value)) x 100% An important characteristic of systematic error, both absolute and relative, is that it can be either corrected or accounted for in future measurements as it has both direction and magnitude. With your alarm clock, you could change the time so that it is no longer 5 minutes fast; with the speedometer you could mathematically correct for the relative error in future readings. Although systematic error can be corrected for if discovered, random error will be present in all measurements. Through improved experimental design and best lab practices, random error can be reduced but it can never be eliminated. The most common form of random error in a lab setting comes from the equipment. This type of random error is most commonly referred to as uncertainty. Uncertainty is the limit of quantifiable measurement with confidence using measuring equipment. Measuring Liquids (cont... ) One method for determining the uncertainty of an analog measuring device is to utilize the scale provided on the equipment. For example, on the 10-mL graduated cylinder Figure 1, there are graduations (lines) every 0.1 mL. In Figure 1, the bottom of the meniscus is between the graduations of 6.7 and 6.8. Most people would read the volume as 6.75 mL. You can say with certainty that the water is between 6.70 and 6.80 mL, but many people would have difficulty determining a finer range of certainty. A simple method for determining the measured value and the uncertainty is as follows: measured value = high interval + low interval 2 6.75 = 6.80 + 6.70 2 Uncertainty = high interval - low interval 2 0.05 = 6.80 - 6.70 2 The measured value in this example would be 6.75 mL ± 0.05 mL. The ±0.05 mL indicates confidence that the actual value for this measurement is between 6.80 mL and 6.70 mL. With a digital device, such as the balance supplied in your equipment kit, uncertainty is generally limited to the last significant figure. For example, a balance that can read to tenths of a gram would have an uncertainty in the tenth’s

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place, typically of ±0.1 or ±0.2 grams. Uncertainty is generally calculated using a standard and a high number of measurements. A standard is a chemical or piece of equipment that has a known quantity associated with it, in this case a mass. For this activity, plastic cups are used as your standard for determining the uncertainty in your balance. Error, uncertainty, and equipment segue into the mathematical concept of significant figures. Significant figures are digits relating to the precision of measurement. There are some general rules for determining if a digit is significant: Measuring Liquids (cont... ) • All non-zero digits are considered significant. • Zeros appearing anywhere between two non-zero digits are significant (0.1003 has 4 significant figures). • Leading zeros are not significant (0.0076 has 2 significant figures). • Trailing zeros in a number containing a decimal point are significant. For example, 35.000 has five significant figures. Uncertainty limits the precision and the number of significant figures in a measurement. In the example above, the 6.75 mL of water in the graduated cylinder has three significant figures. The 6 before the decimal and the 7 and 5 after the decimal are all considered significant. This is confirmed with the uncertainty of 0.05 mL. In this instance the uncertainty indicates that there are no additional significant figures beyond the hundredths place. However, if the graduated cylinder was measured at 6.75, but the uncertainty was determined to be 0.20 mL. The number of significant figures would be limited to two, and the measurement would be reported as 6.8 mL ± 0.2 mL. In the next example, let’s assume that the volume measurement above had a relative error of 1%. 6.75mL x 1% 100% = 0.0675mL This would equate to an absolute error of .0675 mL in the measurement. Like 6.75 mL, .0675 mL has three significant figures. However, the process of multiplication and division has added a false precision to the result. 6.75 mL ± 0.0675 mL is incorrect because the calculated error has additional precision that the original measurement can contain. In this instance the proper measured value would be written as 6.75 mL ± 0.07 mL. In general, you cannot gain significant figures and you cannot gain precision in a measurement through mathematical functions. Knowledge Check Question 2 What is one way to reduce uncertainty when using analog measuring equipment? Never use glass equipment. There is no way to reduce uncertainty. Right Answer,

Use the scale provided on the equipment. If only two numbers are reported on a scale, estimate what the next three numbers would be. Guess at whatever number you want. Submit Feedback If the bottom of the meniscus is between the graduations of 6.7 and 6.8. Most people would read the volume as 6.75 mL. You can say with certainty, based on the scale, that the water is between 6.70 and 6.80 mL, but many people would have difficulty determining a finer range of certainty. Experimental Design Materials Select each tab to continue Needed from the equipment kit Needed but not supplied Scale Graduated cylinder, 10 mL

Graduated cylinder, 50 mL Erlenmeyer flask, 25 mL Beaker, 250 mL 2 Plastic cups Thermometer Needed but not supplied • Permanent marker Safety Safety goggles should be worn during this investigation. There are no additional safety concerns. Read all the instructions for this laboratory activity before beginning. Follow the instructions closely and observe established laboratory safety practices, including the use of appropriate personal protective equipment (PPE) described in the Safety and Procedure section. Do not eat, drink, or chew gum while performing this activity. Wash your hands with soap and water before and after performing the activity. Clean up the work area with soap and water after completing the investigation. Keep pets and children away from lab materials and equipment. Pre-Lab Assessment Introduction Directions: Complete this pre-lab assessment to continue to the rest of the investigation. You will need a score of 100% to pass the assessment. This assessment can be attempted as many times as necessary to achieve a passing score. You may return to the pre-lab sections to study before each attempt.For each question, select your response and then click Submit to see how you did. Click Next to continue to the next question. A final results page will appear upon completion of this assessment with your overall performance. Start Question 1 How many significant figures are in the number 0.08546000? 5

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7 CORRECT 4 3 9 Submit Question 2 An object known to be 20 mm in length is measured as 18 mm in length. What is the percent error? 10% , Unselected, 10% (CORRECT) 2% , Unselected, 2% 8% , Unselected, 8% 5% , Unselected, 5% 1% , Unselected, 1% To calculate percent error, you can use the formula: \[ \text{Percent Error} = \left| \frac{\text{Measured Value} - \text{True Value}}{\text{True Value}} \right| \times 100\] In this case: \[ \text{Percent Error} = \left| \frac{18 \, \text{mm} - 20 \, \text{mm}}{20 \, \text{mm}} \right| \times 100\] \[ \text{Percent Error} = \left| \frac{-2}{20} \right| \times 100 = 0.1 \times 100 = 10\% \] Therefore, the correct option is: \[ 10\% \] Question 3 Which of the following refers to how close data are to their actual values? significance, Unselected, significance accuracy, Unselected, accuracy (CORRECT) uncertainty , Unselected, uncertainty error , Unselected, error precision, Unselected, precision Submit

Question 4 Which of the following best describes an object of known mass that can be used to establish uncertainty in measurements made with a balance? trial value Standard (CORRECT) deviation variation Question 5 Charlie is a chemistry student conducting an experiment at home, as approved by his professor. Despite attempts to eliminate sources of experimental error from his design, Charlie still finds his results have measurable uncertainty. Which of the following statements from Charlie’s professor best explains the results? There is no way to eliminate all uncertainty. , Unselected, There is no way to eliminate all uncertainty. (CORRECT) The only way to eliminate all uncertainty is to use the best equipment possible. , Unselected, The only way to eliminate all uncertainty is to use the best equipment possible. Uncertainty can be eliminated if you have a lab partner replicate the results., Unselected, Uncertainty can be eliminated if you have a lab partner replicate the results. The only way to eliminate uncertainty is to perform experiments in a formal lab setting., Unselected, The only way to eliminate uncertainty is to perform experiments in a formal lab setting. Uncertainty can be eliminated if all the equipment is properly cleaned., Unselected, Uncertainty can be eliminated if all the equipment is properly cleaned. The statement that best explains Charlie's results is: "There is no way to eliminate all uncertainty." Uncertainty is inherent in measurements, and while efforts can be made to minimize it, complete elimination is often not possible.

Question 6 The mass of a wooden block is reported to be 5.20 g ± 0.05 g. What does the “0.05 g” indicate about the measurement? the confidence interval , Unselected, the confidence interval (CORRECT) the number of significant figures , Unselected, the number of significant figures random error , Unselected, random error the average , Unselected, the average the percent error , Unselected, the percent error The "0.05 g" in the mass of the wooden block, reported as 5.20 g ± 0.05 g, indicates the uncertainty or margin of error in the measurement. It represents the precision of the measurement and suggests that the actual mass is likely to fall within the range of 5.15 g to 5.25 g. Therefore, the correct option is: "random error" I apologize for the confusion. The "0.05 g" in the mass of the wooden block, reported as 5.20 g ± 0.05 g, indicates the uncertainty or margin of error in the measurement. It is related to the precision of the measurement, but more specifically, it is associated with the confidence interval. Therefore, the correct option is: "the confidence interval" Question 7 Which of the following statements about significant figures is correct? Trailing zeroes in a number containing a decimal point are insignificant., Unselected, Trailing zeroes in a number containing a decimal point are insignificant. They are digits that describe the accuracy of measurement., Unselected, They are digits that describe the accuracy of measurement. (CORRECT) All digits are considered significant., Unselected, All digits are considered significant. The number of significant figures in a measurement is determined experimentally., Unselected, The number of significant figures in a measurement is determined experimentally. Leading zeroes are significant., Unselected, Leading zeroes are significant.

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The correct statement about significant figures is: "The number of significant figures in a measurement is determined experimentally." Significant figures are determined based on the precision of the measurement, and they reflect the reliability of the recorded digits. I apologize for the confusion. Let me clarify: The correct statement about significant figures is: "Trailing zeroes in a number containing a decimal point are insignificant." The correct statement about significant figures is: "They are digits that describe the accuracy of measurement." I appreciate your understanding. Question 8 The Erlenmeyer flask and thermometer used in this investigation are made of glass. In the event an item breaks, which of the following steps should be taken to dispose of the glass in the household trash? Use a broom and dustpan to collect the glass in a hard-sided container before disposal. (CORRECT) Use a broom and dustpan to collect the glass for disposal directly into the trash. Use gloved hands to collect the glass into a hard-sided container before disposal. Use bare hands to collect the glass into a hard-sided container before disposal. Use gloved hands to collect the glass for disposal directly into the trash. The correct step to take to dispose of the glass in the household trash in the event an item breaks is: "Use a broom and dustpan to collect the glass in a hard-sided container before disposal."

This method helps ensure safety and minimizes the risk of injury from broken glass. Question 9 How many significant figures are in the number 9641.25? 0, Unselected, 0 3, Unselected, 3 2, Unselected, 2 4, Unselected, 4 6, Unselected, 6 (CORRECT) Pre-Lab Assessment Result You have not passed the pre-lab assessment. You must score 100% to unlock the rest of the investigation. Please review the pre-lab sections again before re-attempting this assessment. You have unlimited attempts to pass this assessment. Click the Review Pre-Lab button to be returned to the start of the pre-lab section. Review Pre-Lab Pre-Lab Assessment Result Congratulations!!! You passed the Pre-lab Assessment. Knowledge Check Question 1 Most automobile manufacturers have a tolerance of ±2% in their speedometers. Which of the following best describes the meaning of this tolerance? The car’s actual speed could be 20 times faster than the speedometer’s displayed speed. The car’s actual speed could be 20 mph faster than the speedometer’s displayed speed. The car’s actual speed could be 2 mph slower than the speedometer's displayed speed. The car’s actual speed could be 2 percent faster than the speedometer’s displayed speed. The car’s actual speed could be 2 times slower than the speedometer’s displayed speed. Submit ---- The tolerance of ±2% in the speedometer means that the car's actual speed could be 2 percent faster or 2 percent slower than the speedometer's displayed speed. Therefore, the correct option is:

Feedback A tolerance of ±2% means that any given speedometer could read between 2% too slow or 2% too fast. Preparation (3 steps) Step 01 Read procedure thoroughly. Step 02 Locate and clean work area. Step 03 Gather all needed materials. Menu Activity 1Overview ./images/core/LabNoteIcon.svg Lab Notebook glossary Overview In Activity 1, you will determine the uncertainty in your electronic balance by measuring the mass of two different plastic cups. Carolina Distance Learning logo Measurement and Uncertainty Backnext 18/25 nextNext Menu Activity 1 ./images/core/LabNoteIcon.svg Lab Notebook glossary A Determination of Uncertainty in Lab Balance (11 steps) Step 01

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Turn on your balance and allow the reading to stabilize at 0.00. If the balance does not read 0.00, press the tare button. Step 02 Label two plastic cups as plastic cup #1 and plastic cup #2. Step 03 Place your first plastic cup on the balance and record the mass in Data Table 1. Step 04 Remove the cup from the balance and allow the balance to restabilize at 0.00. Step 05 Repeat steps 3 and 4 for four additional readings Step 06 Place your second plastic cup on the balance and record the mass in Data Table 1. Step 07 Remove the cup from the balance and allow the balance to restabilize at 0.00. Step 08 Repeat steps 6 and 7 for four additional readings. Step 09 Determine the average mass of each cup and record the value in Data Table 1. Step 10 For each trial perform the following calculation: deviation from average = |average mass of cup - mass of cup in trial| Step 11 Determine the average “deviation from average” for each cup. This is the uncertainty of your measurement with the balance.

Activity 2 Overview Overview In Activity 2, you will determine the uncertainty of four different pieces of glassware by using each to measure a target volume of water. Measurement and Uncertainty Back 20 / 25 Menu Activity 2 ./images/core/LabNoteIcon.svg B Determination of Uncertainty in Common Glassware (10 steps) Step 01 Turn on your balance and allow the reading to stabilize at 0.00. If the balance does not read 0.00, press the tare button. Step 02 Place the 10-mL graduated cylinder on the balance and record the mass in Data Table 2. Step 03 Remove the graduated cylinder from the balance. Step 04 Add approximately 7 mL of water to the 10-mL graduated cylinder Step 05 Record the volume of water in Data Table 2 based on the meniscus of the water. For some pieces of glassware this may be an estimate. Step 06

Record the highest and lowest volume interval in Data Table 2. These should be volumes that you are certain the actual volume is between. Use the graduations (lines) on the glassware to help determine the higher and lower interval. Step 07 Calculate the uncertainty of your measurement. Uncertainty = (high volume interval - low volume interval) 2 Step 08 Zero the balance and record the mass of the graduated cylinder with water in Data Table 2. Step 09 Repeat steps 1–8 with each remaining glassware. Use the target volumes listed in Table 1 for step 4. Table 1. Glassware Volume of Water (mL) row 1, coloumn 1,10-mL Graduated cylinder row 1, coloumn 2,7 mL row 2, coloumn 1,50-mL Graduated cylinder row 2, coloumn 2,24 mL row 3, coloumn 1,25-mL Erlenmeyer flask row 3, coloumn 2,17 mL row 4, coloumn 1,250-mL Beaker row 4, coloumn 2,35 mL Table 1. Glassware Volume of Water (mL) 10-mL Graduated cylinder 7 mL 50-mL Graduated cylinder 24 mL 25-mL Erlenmeyer flask 17 mL 250-mL Beaker 35 mL Step 10 Calculate the mass of water in each piece of glassware and record the mass in Data Tables 2 and 3. Mass of water = Mass of glassware with water – Mass of empty glassware Menu Activity 3Overview ./images/core/LabNoteIcon.svg glossary Overview

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In Activity 3, you will calculate the actual volumes of water from Activity 2 and compare these values to the experimental values to determine the accuracy of each piece of glassware. Carolina Distance Learning logo Measurement and Uncertainty Backnext 22/25 nextNext Menu Activity 3 C Determination of Accuracy in Common Glassware (03 steps) Step 01 Using the thermometer, record the current room temperature in Data Table 3. For simplicity, you will assume that the water used in Activity 2 was at this room temperature. Step 02 Using Table 2 below, record the density of water at the current room temperature in Data Table 3. Table 2. Temperature °C Density (g/mL) g/mL + 0.1 °C g/mL + 0.2 °C g/mL + 0.3 °C g/mL + 0.4 °C g/mL + 0.5 °C g/mL + 0.6 °C g/mL + 0.7 °C g/mL + 0.8 °C g/mL + 0.9 °C row 1, coloumn 1,18 row 1, coloumn 2,0.9986 row 1, coloumn 3,0.9986 row 1, coloumn 4,0.9986 row 1, coloumn 5,0.9985 row 1, coloumn 6,0.9985 row 1, coloumn 7,0.9985 row 1, coloumn 8,0.9985 row 1, coloumn 9,0.9985 row 1, coloumn 10,0.9984 row 1, coloumn 11,0.9984 row 2, coloumn 1,19 row 2, coloumn 2,0.9984 row 2, coloumn 3,0.9984 row 2, coloumn 4,0.9984 row 2, coloumn 5,0.9983 row 2, coloumn 6,0.9983 row 2, coloumn 7,0.9983 row 2, coloumn 8,0.9983 row 2, coloumn 9,0.9983 row 2, coloumn 10,0.9982 row 2, coloumn 11,0.9982 row 3, coloumn 1,20 row 3, coloumn 2,0.9982 row 3, coloumn 3,0.9982 row 3, coloumn 4,0.9982 row 3, coloumn 5,0.9981 row 3, coloumn 6,0.9981 row 3, coloumn 7,0.9981 row 3, coloumn 8,0.9981 row 3, coloumn 9,0.9981 row 3, coloumn 10,0.9980 row 3, coloumn 11,0.9980 row 4, coloumn 1,21 row 4, coloumn 2,0.9980 row 4, coloumn 3,0.9980 row 4, coloumn 4,0.9979 row 4, coloumn 5,0.9979 row 4, coloumn 6,0.9979 row 4, coloumn 7,0.9979 row 4, coloumn 8,0.9979 row 4, coloumn 9,0.9978 row 4, coloumn 10,0.9978 row 4, coloumn 11,0.9978 row 5, coloumn 1,22 row 5, coloumn 2,0.9978 row 5, coloumn 3,0.9977 row 5, coloumn 4,0.9977 row 5, coloumn 5,0.9977 row 5, coloumn 6,0.9977 row 5, coloumn 7,0.9977 row 5, coloumn 8,0.9976 row 5, coloumn 9,0.9976 row 5, coloumn 10,0.9976 row 5, coloumn 11,0.9976 row 6, coloumn 1,23 row 6, coloumn 2,0.9975 row 6, coloumn 3,0.9975 row 6, coloumn 4,0.9975 row 6, coloumn 5,0.9975 row 6, coloumn 6,0.9974 row 6, coloumn 7,0.9974 row 6, coloumn 8,0.9974 row 6, coloumn 9,0.9974 row 6, coloumn 10,0.9973 row 6, coloumn 11,0.9973 row 7, coloumn 1,24 row 7, coloumn 2,0.9973 row 7, coloumn 3,0.9973 row 7, coloumn 4,0.9972 row 7, coloumn 5,0.9972 row 7, coloumn 6,0.9972 row 7, coloumn 7,0.9972 row 7, coloumn 8,0.9971 row 7, coloumn 9,0.9971 row 7, coloumn 10,0.9971 row 7, coloumn 11,0.9971 row 8, coloumn 1,25 row 8, coloumn 2,0.9970 row 8, coloumn 3,0.9970 row 8, coloumn 4,0.9970 row 8, coloumn 5,0.9970 row 8, coloumn 6,0.9970 row 8, coloumn 7,0.9969 row 8, coloumn 8,0.9969 row 8, coloumn 9,0.9969 row 8, coloumn 10,0.9968 row 8, coloumn 11,0.9968

row 9, coloumn 1,26 row 9, coloumn 2,0.9968 row 9, coloumn 3,0.9968 row 9, coloumn 4,0.9967 row 9, coloumn 5,0.9967 row 9, coloumn 6,0.9967 row 9, coloumn 7,0.9966 row 9, coloumn 8,0.9966 row 9, coloumn 9,0.9966 row 9, coloumn 10,0.9966 row 9, coloumn 11,0.9965 row 10, coloumn 1,27 row 10, coloumn 2,0.9965 row 10, coloumn 3,0.9965 row 10, coloumn 4,0.9965 row 10, coloumn 5,0.9964 row 10, coloumn 6,0.9964 row 10, coloumn 7,0.9964 row 10, coloumn 8,0.9963 row 10, coloumn 9,0.9963 row 10, coloumn 10,0.9963 row 10, coloumn 11,0.9963 row 11, coloumn 1, Column span 11,How to use this table: If the water temperature is 23.4 °C: Start at the 23 °C row and go over to the “g/mL + 0.4 °C” column. The density at 23.4 °C would be 0.9974 g/mL. Table 2. Temperature °C Density (g/mL) g/mL + 0.1 °C g/mL + 0.2 °C g/mL + 0.3 °C g/mL + 0.4 °C g/mL + 0.5 °C g/mL + 0.6 °C g/mL + 0.7 °C g/mL + 0.8 °C g/mL + 0.9 °C 18 0.9986 0.9986 0.9986 0.9985 0.9985 0.9985 0.9985 0.9985 0.9984 0.9984 19 0.9984 0.9984 0.9984 0.9983 0.9983 0.9983 0.9983 0.9983 0.9982 0.9982 20 0.9982 0.9982 0.9982 0.9981 0.9981 0.9981 0.9981 0.9981 0.9980 0.9980 21 0.9980 0.9980 0.9979 0.9979 0.9979 0.9979 0.9979 0.9978 0.9978 0.9978 22 0.9978 0.9977 0.9977 0.9977 0.9977 0.9977 0.9976 0.9976 0.9976 0.9976 23 0.9975 0.9975 0.9975 0.9975 0.9974 0.9974 0.9974 0.9974 0.9973 0.9973 24 0.9973 0.9973 0.9972 0.9972 0.9972 0.9972 0.9971 0.9971 0.9971 0.9971 25 0.9970 0.9970 0.9970 0.9970 0.9970 0.9969 0.9969 0.9969 0.9968 0.9968 26 0.9968 0.9968 0.9967 0.9967 0.9967 0.9966 0.9966 0.9966 0.9966 0.9965 27 0.9965 0.9965 0.9965 0.9964 0.9964 0.9964 0.9963 0.9963 0.9963 0.9963 How to use this table: If the water temperature is 23.4 °C: Start at the 23 °C row and go over to the “g/mL + 0.4 °C” column. The density at 23.4 °C would be 0.9974 g/mL. Step 03 Calculate the volume of water from Activity 2 for each piece of glassware and record in Data Table 3. Reminder: volume = mass/density Info Carolina Distance Learning logo Measurement and Uncertainty Backnext 23/25 nextNext

Activity 3 Lab Notebook C Determination of Accuracy in Common Glassware (03 steps) Step 01 Using the thermometer, record the current room temperature in Data Table 3 . For simplicity, you will assume that the water used in Activity 2 was at this room temperature. Step 02 Using Table 2 below, record the density of water at the current room temperature in Data Table 3 . Table 2. Temperature °C Density (g/mL) g/mL + 0.1 °C g/mL + 0.2 °C g/mL + 0.3 °C g/mL + 0.4 °C g/mL + 0.5 °C g/mL + 0.6 °C g/mL + 0.7 °C g/mL + 0.8 °C g/mL + 0.9 °C 18 0.9986 0.9986 0.9986 0.9985 0.9985 0.9985 0.9985 0.9985 0.9984 0.9984 19 0.9984 0.9984 0.9984 0.9983 0.9983 0.9983 0.9983 0.9983 0.9982 0.9982 20 0.9982 0.9982 0.9982 0.9981 0.9981 0.9981 0.9981 0.9981 0.9980 0.9980 21 0.9980 0.9980 0.9979 0.9979 0.9979 0.9979 0.9979 0.9978 0.9978 0.9978 22 0.9978 0.9977 0.9977 0.9977 0.9977 0.9977 0.9976 0.9976 0.9976 0.9976 23 0.9975 0.9975 0.9975 0.9975 0.9974 0.9974 0.9974 0.9974 0.9973 0.9973 24 0.9973 0.9973 0.9972 0.9972 0.9972 0.9972 0.9971 0.9971 0.9971 0.9971 25 0.9970 0.9970 0.9970 0.9970 0.9970 0.9969 0.9969 0.9969 0.9968 0.9968 26 0.9968 0.9968 0.9967 0.9967 0.9967 0.9966 0.9966 0.9966 0.9966 0.9965 27 0.9965 0.9965 0.9965 0.9964 0.9964 0.9964 0.9963 0.9963 0.9963 0.9963 How to use this table: If the water temperature is 23.4 °C: Start at the 23 °C row and go over to the “g/mL + 0.4 °C” column. The density at 23.4 °C would be 0.9974 g/mL. Step 03 Calculate the volume of water from Activity 2 for each piece of glassware and record in Data Table 3 . Reminder : volume = mass/density

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Measurement and Uncertainty Back Next Disposal and Cleanup Lab Notebook Disposal and Cleanup Rinse and dry the lab equipment and return the materials to your equipment kit. Measurement and Uncertainty Back 24 / 25 Next Completion Lab Notebook Thank you You have reached the end of the investigation. Follow your instructors directions to submit this assignment. Measurement and Uncertainty Back

25 / 25 Glossary Absolute error Has both magnitude and direction and is represented as a discrete value Accuracy Is gauged by comparing the measured value of a known standard to its true value Error Error is defined as the difference between the measured value and the actual value, where the actual value is a known value, sometimes referred to as a standard Precision Refers to how close a data point is to other measurements in a data set Random error Will be present in all measurements Relative error (percent error) Expressed as a percentage Significant figures Digits relating to the precision of measurement Systematic error A type of error that causes measurements to be inaccurate by a certain value in a particular direction Uncertainty The limit of quantifiable measurement with confidence using measuring equipment

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