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Monday, January 9, 2012

Lab #9 - Calculating Density of solids (regular- and irregular-shaped)


Lab #9 - Calculating Density of solids (regular- and irregular-shaped)

All matter has mass and volume.  Mass is a measure of the amount of matter an object has; its units are given in grams (g) or kilograms (kg).  Volume is the amount of space an object occupies; the units for volume liters (l), meters cubed (m3), and gallons (gal).
If we know the mass and volume of an object, then we can use the following equation to calculate its density: D=m/V   Density = mass/Volume
     
The symbol M stands for the mass of the object, and V the volume.  Density has the units of mass divided by volume such as grams per centimeters cubed (g/cm3) or grams per milliliter (g/ml).

Problem
Will a larger object always have a larger density than a smaller one?

Hypothesis





Materials
Triple beam balance
Ruler
Two different sized cubes
Two irregular-shaped objects

Procedure for a regular-shaped object
  1. Measure the mass of your objects using the triple beam balance.  Record your measurements in the data table. 
  2.  Use a ruler to measure the dimensions of your rectangular objects; measure to the nearest tenth (0.1) cm.
Calculate the volume in cm3 of your spherical object by measuring its radius.  Use the following equation to calculate its Volume: Volume of a Sphere = 4/3 π r3
  1. Record your measurements in the data table. 

Results for a regular-shaped spherical object


Mass (g)
Volume (cm3)
Density (g/cm3)
Object 1(marble)



Object 2 (styrofoam sphere)




Radius of marble = ___cm
Radius of Styrofoam sphere = ___  cm
Volume of a Sphere = 4/3 π r3
D=m/V
 (4/3)(3.14)(r)(r)(r)


Analysis for a regular-shaped object

  1. Which object had the greater density? 



  1. A block of wood has a mass of 8 g and occupies a volume of 10 cm3.  What is its density?




Conclusion
(Write a summary of your experiment.  Was your hypothesis right?  What did you learn?  What could you do next time?  Was it fun?  How is this related to what we are learning in class?)

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