Floating Eggs Lab Report PDF

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Floating Eggs Lab Report...

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Floating Eggs Lab Report Introduction: The purpose of the floating eggs lab is to experimentally determine two values for the densities of a raw and hard-boiled egg using Archimedes’ principles that objects less dense than the solution they are immersed in will float and that that the volume of an object is equal to the change in volume of the solution-object system in which it is submerged. Experimental: The first value will be determined using salt-water solutions by bringing the density of the salt water solution up to the density of the eggs and then using the mass of sodium required to reach that point to calculate the density of the salt-water system and the eggs (assumed to be of equal density at the first point where the egg begins to float). The second experimental value of the density will be determined by dropping the eggs in volumetric cylinders full of water and using the water displacement to calculate the volume of the egg. We can use this volume, coupled with the mass, to also determine the density of the eggs. The only deviation from the standard procedure was made in the second portion of this experiment, where density was obtained using a volumetric cylinder. Step 3 says to “Pour about 500 mL of water into the 1000 mL cylinder,” however, we varied the amount of water we began with and recorded this number for each trial. Data Analysis: PART ONE Egg A Initial Mass NaCl (g)

Final Mass NaCl (g) Change in Mass (g)

Trial One

73.93

43.29

36.64

Trial Two

77.01

46.80

30.21

Trial Three

70.58

36.52

34.06

Trial Four

77.49

42.38

35.11

Average Change in Mass: 35.00 g

Egg B Initial Mass NaCl (g)

Final Mass NaCl (g) Change in Mass (g)

Trial One

67.23

30.09

37.14

Trial Two

69.79

22.02

47.77

Trial Three

79.83

36.59

43.24

Trial Four

70.24

29.75

40.49

Average Change in Mass: 42.16 PART TWO Egg A (mass = 62.17 g) Initial Volume Water (mL)

Final Volume Water Change in Volume (mL) (mL)

Trial One

750

805

55

Trial Two

740

800

60

Trial Three

750

805

65

Trial Four

780

832

52

Egg B (mass = 57.81 g) Initial Volume Water (mL)

Final Volume Water Change in Volume (mL) (mL)

Trial One

690

741

51

Trial Two

730

783

53

Trial Three

760

814

54

Trial Four

800

851

51

Discussion Questions Density of Egg A can be calculated by taking the average amount of salt required for floating. 35.00 g / 300 mL + (density of water) = average density of solution when floating began. (35.00 / 300) g/mL + .9982 g/mL = 1.115 g/mL = average density for egg A Repeat for Egg B =  1.139 g/mL = average density for egg B Standard Deviations can be calculated by calculating the individual density values for each trial. For egg A, Trial One Density = 1.121 Trial Two Density = 1.010 Trial Three Density = 1.112 Trial Four Density = 1.116 STDEV for Egg A Density = .05329 Repeat for Egg B = . 009621 = STDEV for Egg B Density For method, 2 the density can be calculated by taking the known mass of the egg and dividing it by the displacement of water it caused. For egg A: Density Trial One = 62.17 g / 55 mL = 1.1 g/mL Density Trial Two = 62.17 g / 60 mL = 1.0 g/mL Density Trial Three = 62.17 g / 65 mL = .96 g/mL Density Trial Four = 62.17 g / 52 mL = 1.2 g/mL

Mean = 1.1 g/mL STDEV = .11 For egg B: Density Trial One = 57.81 g / 51 mL = 1.1 g/mL Density Trial Two = 57.81 g / 54 mL = 1.1 g/mL Density Trial Three = 57.81 g / 53 mL = 1.1 g/mL Density Trial Four = 57.81 g / 51 mL = 1.1 g/mL Mean = 1.1 g/mL STDEV = 0 (because of sig figs)

As you can see,the averages for both Egg A and Egg B using both methods were roughly 1.1g/mL. This means that our data was relatively consistent and there was little error. This also means that there is not a significant difference in the densities of a raw and hard-boiled egg. Method 2 is more accurate because you are basing the density of the egg based on its own mass and volume, whereas in Method 1, you are basing the density of the egg on the principle that it will be equal to the density of the solution at the point where it begins to float. This can cause errors because often times, not all of the solute was dissolved before the egg began to float. We know that Egg A was the raw egg because it was unable to spin for long periods of time when we did the test. This is because, given the egg was raw, its center of gravity kept shifting, causing it to have an unsmooth spinning motion. Egg B was the hard-boiled egg because it spun very easily, given that the center of mass was consistent. The densities, however, of these two types of eggs weren’t significantly different, as they had a similar average density using both methods 1 and 2. According to our data, using method 1, a boiled egg is slightly more dense than a raw egg (1.139 g/mL vs. 1.115 g/mL). However, this difference is not significant, as the standard deviation for the density of the raw egg is .05329 g/mL. In method 2, they had the same average density at 1.1 g/mL. This means that- according to our data- there is no significant difference in the densities of a raw egg versus a boiled egg. Therefore, you can only differentiate a fresh egg and a boiled egg by spinning them, as the center of gravity of a fresh egg is non-constant, so it is unable to spin smoothly for long periods of time. The boiled egg will spin smoothly. 20.4 g NaCl + 10.62 g Sugar in 500.0 mL of water will have a density as follows: .9982 g/mL + (30.02g / 500.0mL) = 1.058 g/mL

Conclusion: From this experiment, we learned how to calculate the density of objects by two means and we drew consistent data about the density of a raw versus a boiled egg. We found that a raw and hard-boiled egg do not have significantly different densities. This result makes sense because the law of conservation of mass states that the mass of the products and reactants in a closed system should be equal. Since the egg has a shell, it makes sense that boiling it did not change the mass and, consequently, did not change the density. Some sources of error in this lab arose from the fact that the raw eggs began to crack during part one of this lab. We frequently had to change eggs in this part, however, we assumed that the density of all raw eggs is equal and thus, were able to use multiple eggs in our data....