Lab Report 1

Scientific Measurement Experiments Your Name Lab Partner: TA: Date 1. Part A: Significant Figures a. Data: Line Length Ruler Markings 1m 1 dm

Line A 0.1 m 0.10 m 0.21 m 0.100 m 0.213 m 0.1000 m 0.2129 m

Line B 0.1 m 0.10 m 0.20 m 0.100 m 0.202 m 0.1000 m 0. 2019 m

Start End 1 cm Start End 1 mm Start End b. Results: Calculated Line Measurements Ruler Markings Line A Line B 1m 0.1 m 0.1 m 1 dm 0.11 m 0.10 m 1 cm 0.113 m 0.102 m 1 mm 0.1129 m 0.1019 m c. Discussion: i. As the units for the measurements become smaller, the more distinguishable the difference of the lengths of the two lines is. Hence, the decimeter markings showed a more distinguishable difference between the lengths of the two lines than the meter markings did and etc. ii. Yes, two significant figures are sufficient because they include the least significant digit. Recording to more digits would have claimed more precision than is legitimate and recording any less would have made the data less valuable.

2. Part B: Volume Measurements Using a Pipet a. Data: Pipet Volume Measured Using a Graduated Cylinder Trial Volume from graduated cylinder (ml) 1 Start: 2.02 ml End: 7.02 ml 2 Start: 1.90 ml End: 6.95 ml 3 Start: 2.81 ml End: 7.90 ml

b. Results: Calculated Volume Measurements Trial Volume from graduated cylinder (ml) 1 5.00 ml 2 5.05 ml 3 5.09 ml Mean and 5.05 ± 0.05 Standard Deviation c. Discussion: i. To measure out 5 ml of something, it is more accurate to use a pipet because the 5 ml pipet has an accuracy of ± 0.02 ml which is closer to the actual measurement compared to the accuracy of the 10 ml graduated cylinder, which is ± 0.1, and the accuracy of the 50 ml beaker, which is ± 2.5 ml. 3. Part C: Mass Measurement a. Purpose: The purpose of this experiment is to distinguish a pre-1982 penny from a post-1982 penny by measuring the difference their masses using an analytical balance. b. Data: Data for Pre-1982 Pennies Pre-1982 Penny Mass (g) Observations 1 3.0913 g Dirty, worn 2 3.1207 g Dirty, worn, chipped 3 3.0814 g Dull, dirty 4 3.0672 g Dirty, worn Experimental total 12.3594 g mass Data for Post-1982 Pennies Post-1982 Penny Mass (g) 1 2.5104 g 2 2.4989 g 3 2.4814 g 4 2.5114 g Experimental total 10.0013 g mass (g)

Observations Slightly dirty and worn Pretty clean Not that worn out Slightly dirty

c. Results: Calculated Total Masses and the Standard Deviation and Mean of the data Results for Pre-1982 Pennies Standard deviation and mean 3.09 ± 0.02 Calculated total mass (g) 12.3606 g

Results for Post-1982 Pennies Standard deviation and mean Calculated total mass (g)

2.50 ± 0.01 10.0021 g

d. Discussion: i. Based on the data, one can distinguish a pre-1982 penny from a post-1982 penny by comparing their masses. From the data, it is evident that the pre-1982 pennies have larger masses than those of post-1982. ii. Because the pre-1982 pennies have larger masses than the ones from post-1982, the zinc metal is denser than the copper metal. The calculated total mass (g) of the Pre-1982 pennies is 12.3606 g while the calculated total mass (g) of the Post-1982 pennies is 10.0021g; therefore, the zinc metal is denser than the copper since the pre-1982 pennies were made from zinc. e. Error Analysis: i. The standard deviation for each set of four pennies is higher compared to the experimental uncertainty due to the balance, which is ±0.0001 g per penny. This shows that due to certain possible instrumental uncertainties and/or experimental errors, the calculated total mass of each set of pennies is somewhat inaccurate. The standard deviation for the pre-1982 pennies have a higher standard deviation than the post-1982, which might be due to the addition of the mass of the dirt on the pre-1982 pennies which is described in the observation part of the data. 4. Graph Preparation a. Data: Beaker Diameter and Circumference Beaker size (ml) 150 ml 250 ml 400 ml 600 ml

Diameter (cm) 5.42 cm 6.50 cm 7.18 cm 8.20 cm

Circumference (cm) 18.62 cm 22.15 cm 25.00 cm 28.65 cm

b. Graph

Diameter vs. Circumfirence of Beakers Circumfirence = Diameter x Pi

30

Circumfirence (cm)

28 26 24 22 20 18 5

5.5

6

6.5

7

7.5

8

8.5

Diameter (cm) c. Results: Slope, Intercept and their respective Standard and Percent Deviations of the data Standard Deviation Percent Deviation Slope 3.6 ± 0.11 ± 15.8 % Intercept -1.2 ± 0.77 ± 139.3 % d. Error Analysis; a. The percent deviation of the slope from the expected value is ± 15.8% because of certain instrumental uncertainties and experimental errors. The string that was used to measure the circumference and diameter of each beaker may have certain uncertainties such that the string may have been pulled more tightly around one beaker compared to another. Also, as the string was measured using a centimeter ruler, it is uncertain whether the string was stretched out more tightly for certain beakers than for others, causing the circumference or diameter measurement to be slightly longer or shorter than the actual measurement. In addition, the accuracy of the ruler used to measure the string is unknown. e. Calculation:

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