Density of a Garden Rock

Results:

Density (gcmˉ ³) = Mass (g) / Volume (cm³)  

Average Density = (Sum of all blocks) / Number of Blocks

Conclusion:

  Rock number one with a mass of 36g was placed in a measuring cylinder of water with a volume of 400cm³. The water rose in the cylinder to 419cm³, therefore the rock’s displaced volume is 19cm³. The density was calculated by dividing the mass of the rock by the volume of the rock, this resulted in the density of 1.8947gcmˉ ³. Rock number two had a bigger mass than both rock number one and rock number three. Rock number two has a density of 2.15gcmˉ ³. It has 7g more than rock number one which has a density of and is 4g more than rock number 3, which resulted in 1.95gcmˉ ³, but rock number two and rock number 3 have equal volume, 20cm³. This is because rock number 3 probably has less dense material in its makeup and rock number 2 had more. The average density of the garden rocks resulted in 1.9982gcmˉ ³. The density of pure calcium carbonate is about 2.83gcmˉ ³, so these rocks are not pure calcium carbonate. They are but a mixture of calcium carbonate and other materials that are less dense than calcium carbonate. If the mass of the rocks increase and volume of the rocks stays constant, density will increase, but if the mass stays constant and the volume increases, then density will decrease.

  Errors that might have occurred could have been systematic errors. Incorrect measurements of the garden rocks’ mass is a significant source of error that could affect the resulting densities. A way to improve the accuracy of your measurements would be to make sure you are measuring with an accurate electronic balance, to read the final measurement a few moments after the rock has been placed on the scale and to make sure no other substance is touching or creating pressure on the sensitive scale, for example, your breath. Another source of error would be to observe the volume of water incorrectly. To improve this in accuracy, make sure to read the amount of water in the cylinder by taking the measurement from the bottom of the meniscus. This can be achieved by becoming eye level with the meniscus and also by asking a friend to check to see if you read the meniscus properly. Another source of error could be a miscalculation of the volume, density or average density of the garden rocks. To improve the accuracy of your calculations, write down each figure to multiply, divide or add with appropriate labels in your table. Next, take your time performing the necessary calculations slowly on a calculator. To make sure the calculations are correct, have a friend check it over with a different calculator.