Determination of Density Essay

Purpose: To determine the densities of aluminum and zinc cylinders Density is the relationship between the mass of an object and its volume. Sometimes density can be easy to sense. If two objects have exactly the same shape and size, the denser one may feel heavier. If their densities are close together, it can be hard to tell the difference. It gets really tough if you are dealing with materials that have very different sizes or very different shapes. The only way to decide the density of an object is to measure its mass and its volume, then divide. Ex. Density= Mass/Volume Procedure: For Aluminum: 1. Weigh the aluminum cylinders individually on the analytical balance to the nearest 0.0001g and record the weights 2. With a vernier caliper, measure the diameter of each cylinder to the nearest 0.01cm and record 3. Again, using the vernier caliper, measure the length of each cylinder to the nearest 0.01cm and record 4. Compute the volume of each cylinder by using the formula V= (3.14d2h)/4 For Zinc: 1. Weigh the zinc cylinders individually on the top loading balance to the nearest 0.01g, and record the weights 2. Place enough water in a 100mL graduated cylinder to cover the object. Record the volume of water to the nearest 0.1mL by reading the bottom of the meniscus 3. Place the zinc cylinder in the graduated cylinder. Read the new volume and determine the volume for each piece of zinc Data: Density of Zinc Mass#1 104.0168gVolume#1 18mLDensity#1 5.7780g/cm3 Mass#2 92.8178gVolume#2 15mLDensity#2 6.1876g/cm3 Mass#3 72.2115gVolume#3 10mLDensity#3 7.2215g/cm3 Mass#4 55.3077gVolume#4 9mLDensity#4 6.1453g/cm3 Mass#5 35.2653gVolume#5 7mLDensity#5 5.0379g/cm3 Average Density 6.079g/cm3 Density of Aluminum Mass#1 26.48gVolume#1 6.28mLDensity#1 4.22g/cm3 Mass#2 21.50gVolume#2 5.01mLDensity#2 4.30g/cm3 Mass#3 17.58gVolume#3 4.14mLDensity#3 4.25g/cm3 Mass#4 13.10gVolume#4 2.92mLDensity#4 4.48g/cm3 Mass#5 8.68gVolume#5 2.04mLDensity#5 4.25g/cm3 Diameter = 1.025cm Average Density 4.29g/cm3 Conclusions: The densities of both objects were successfully determined. The average density of the aluminum cylinders was 4.29g/cm3, and the density of the zinc cylinders was 6.079g/cm3. Both of these values seem reasonable, and the zinc seems to be slightly heavier than the aluminum. The density of the zinc cylinders was found using the volume by displacement method, and the volume of the aluminum cylinders was found by the formula method V= (3.14d2h)/4. Problems with the equipment may have possibly introduced error into the measurements. The 100mL graduated cylinder used to find the volume of the zinc cylinders was only marked in 10mL increments, requiring estimation for levels in between. The volume of the aluminum cylinders required the use of the vernier caliper to measure the diameter and the length of each cylinder. Improper use of the vernier caliper may have altered the measurements received for the aluminum cylinders. The error introduced by these problems was slight, however, and the calculated densities for both objects are probably quite reliable.