# Chemistry/Density

Science 8 Experiment
CALCULATING THE DENSITY OF WATER, A BLOCK OF WOOD AND A ROCK SAMPLE

PURPOSE: The purpose of this experiment is to find the density of distilled water, the density of a sample of wood, the density of a rock sample and discover how density determines whether an object sinks or floats in water.

MATERIAL:

balance
block of wood
distilled water large beaker
centimetre ruler
rock sample

DATA:

mass of 25 mL graduated cylinder = _______________________
mass of graduated cylinder + 25.0 mL of water = ____________________
number of rock sample = __________
mass of rock sample = _______________________
volume of water in 250 mL graduated cylinder =_______________________
volume of water in 250 mL graduated cylinder after adding rock = ______________________
what happens to rock when placed in water: _________________________
number of wood block = __________
mass of wood block = _______________________
dimensions of wood block: length = _______________________
what happens to wood block when placed in water: ___________________________________

DISCUSSION:
IMPORTANT NOTE: In all the questions and calculations that follow, you must say what you are doing or calculating. If numbers are being subtracted or multiplied together the numbers involved in the calculation must be shown and the result written down; if a special equation is being used the equations must be shown, the numbers being used must be shown as they are used in the equation and the results of the calculation must be shown.

1. (a) Calculate the mass of the water in the 25 mL graduated cylinder.

(b) Calculate the density of the sample of distilled water using the following formula. Round your answer off to three decimal places.

2.(a) Calculate the volume of the rock sample.

(b) Calculate the density of the rock sample using the following formula. Round your answer off to two decimal places.

3. (a) Calculate the volume of the wood block. The units are “cm3 ”. What is this volume when expressed in “mL”?

(b) Calculate the density of the wood block using the following formula. Round your answer off to three decimal places.

4. Fill in the following table.

Object Density of Object Density of Water Does object float or sink in water? Is object’s density greater or less than water’s density?
rock
wood

5. Write out and complete the following sentences using the information in the above table.

Objects having a density greater than the density of water will _____________ when placed in water. Objects having a density less than the density of water will _____________ when placed in water.