Difference between revisions of "Density"
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: An [[object]] with a small amount of [[mass]] spread over a large [[Volume (Space)|volume]] is said to have a low [[density]]. | : An [[object]] with a small amount of [[mass]] spread over a large [[Volume (Space)|volume]] is said to have a low [[density]]. | ||
: The [[SI Unit|units]] of [[density]] are kg/m<sup>3</sup>. | : The [[SI Unit|units]] of [[density]] are kg/m<sup>3</sup>. | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | |[[File:ParticleModelSolidLiquidGas.png|center|500px]] | ||
| + | |- | ||
| + | | style="height:20px; width:200px; text-align:center;" |[[Solid]]s are the most dense [[State of Matter|state of matter]] because there are a large number of [[particle]]s in a certain [[Volume (Space)|volume]] and [[gas]]es are the least '''dense''' [[State of Matter|state of matter]] because there are a small number of [[particle]]s in a the same [[Volume (Space)|volume]]. | ||
| + | |} | ||
| + | |||
| + | ===Density and Floating=== | ||
| + | : If an [[object]] is more '''dense''' than [[water]] it will sink. | ||
| + | : If an [[object]] is less '''dense''' than [[water]] it will rise through [[water]] and float on the surface. | ||
| + | |||
| + | ===Equation=== | ||
| + | : Density = Mass/volume | ||
| + | :<math>\rho = \frac{m}{V}</math> | ||
| + | Where: | ||
| + | : ρ = [[density]] | ||
| + | : m = [[mass]] | ||
| + | : V = [[Volume (Space)|volume]] | ||
| + | |||
| + | ===Example Calculations=== | ||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | | style="height:20px; width:200px; text-align:center;" |'''5000[[kg]] of [[Iron]] has a [[volume]] of 0.635m<sup>3</sup>. Calculate the density of [[Iron]].''' | ||
| + | | style="height:20px; width:200px; text-align:center;" |'''A 50,000cm<sup>3</sup> container of [[water]] is full with a 50[[kg]] [[mass]] of [[water]]. Calculate the density of [[water]].''' | ||
| + | | style="height:20px; width:200px; text-align:center;" |'''A 200,000cm<sup>3</sup> [[volume]] of [[air]] has a [[mass]] of 245[[g]]. Calculate the density of [[air]]. | ||
| + | |- | ||
| + | | style="height:20px; width:200px; text-align:left;" | | ||
| + | [[Mass]] = 5000[[kg]] | ||
| + | |||
| + | [[Volume (Space)|Volume]] = 0.635m<sup>3</sup> | ||
| + | |||
| + | :<math>\rho = \frac{m}{V}</math> | ||
| + | |||
| + | :<math>\rho = \frac{5000}{0.635}</math> | ||
| + | |||
| + | :<math>\rho = 7874kg/m^3</math> | ||
| + | | style="height:20px; width:200px; text-align:left;" | | ||
| + | [[Mass]] = 50[[kg]] | ||
| + | |||
| + | [[Volume (Space)|Volume]] = 50,000cm<sup>3</sup> = 0.05m<sup>3</sup> | ||
| + | |||
| + | :<math>\rho = \frac{m}{V}</math> | ||
| + | |||
| + | :<math>\rho = \frac{50}{0.05}</math> | ||
| + | |||
| + | :<math>\rho = 1000kg/m^3</math> | ||
| + | | style="height:20px; width:200px; text-align:left;" | | ||
| + | [[Mass]] = 245[[g]] = 0.245[[kg]] | ||
| + | |||
| + | [[Volume (Space)|Volume]] = 200,000cm<sup>3</sup> = 0.2m<sup>3</sup> | ||
| + | |||
| + | :<math>\rho = \frac{m}{V}</math> | ||
| + | |||
| + | :<math>\rho = \frac{0.245}{0.2}</math> | ||
| + | |||
| + | :<math>\rho = 1.225kg/m^3</math> | ||
| + | |} | ||
| + | |||
| + | ==Key Stage 4== | ||
| + | ===Meaning=== | ||
| + | [[Density]] is the amount of [[mass]] per [[unit]] [[Volume (Space)|volume]] of an [[object]]. | ||
| + | |||
| + | ===About Density=== | ||
| + | : An [[object]] with a large amount of [[mass]] in a small [[Volume (Space)|volume]] is said to have a high [[density]]. | ||
| + | : An [[object]] with a small amount of [[mass]] spread over a large [[Volume (Space)|volume]] is said to have a low [[density]]. | ||
| + | : The [[SI Unit|units]] of [[density]] are kg/m<sup>3</sup>. | ||
| + | |||
| + | ===Finding the Density=== | ||
| + | ====Finding The Density of a Regular Object==== | ||
| + | : A regular [[object]] is a [[solid]] in the shape of a [[cuboid]]. | ||
| + | #Measure the [[mass]] of the [[cuboid]] using an [[Electronic Balance]] or [[Measuring Scale]]. | ||
| + | #Measure the length, width and height of the [[cuboid]]. | ||
| + | #Multiply the length, width and height to calculate the [[Volume (Space)|volume]]. | ||
| + | #Divide the [[mass]] by the [[Volume (Space)|volume]] of the [[cuboid]] to calculate the [[density]]. | ||
| + | |||
| + | ====Finding The Density of an Irregular Object==== | ||
| + | : An irregular [[object]] is a [[solid]] whose shape prevents the sides being measured by a [[ruler]]. | ||
| + | #Measure the [[mass]] of the [[object]] using an [[Electronic Balance]] or [[Measuring Scale]]. | ||
| + | #Fill a [[Measuring Cylinder|measuring cylinder]] with enough [[water]] to [[submerse]] the [[object]]. | ||
| + | #Take a reading of the [[Volume (Space)|volume]] of [[water]] in the [[Measuring Cylinder]]. | ||
| + | #Place the [[object]] in the [[Measuring Cylinder]] and ensure it is [[submerse]]d. | ||
| + | #Take a reading of the [[Volume (Space)|volume]] of [[water]] + [[object]] in the [[Measuring Cylinder]]. | ||
| + | #Subtract the [[Volume (Space)|volume]] of [[water]] from the [[Volume (Space)|volume]] of [[water]] + [[object]] to find the [[Volume (Space)|volume]] of the [[object]]. | ||
| + | #Divide the [[mass]] by the [[Volume (Space)|volume]] of the [[object]] to calculate the [[density]]. | ||
{| class="wikitable" | {| class="wikitable" | ||
Revision as of 15:25, 5 March 2019
Contents
Key Stage 3
Meaning
Density is the amount of mass per unit volume of an object.
About Density
- An object with a large amount of mass in a small volume is said to have a high density.
- An object with a small amount of mass spread over a large volume is said to have a low density.
- The units of density are kg/m3.
 |
| Solids are the most dense state of matter because there are a large number of particles in a certain volume and gases are the least dense state of matter because there are a small number of particles in a the same volume. |
Density and Floating
- If an object is more dense than water it will sink.
- If an object is less dense than water it will rise through water and float on the surface.
Equation
- Density = Mass/volume
\[\rho = \frac{m}{V}\] Where:
Example Calculations
| 5000kg of Iron has a volume of 0.635m3. Calculate the density of Iron. | A 50,000cm3 container of water is full with a 50kg mass of water. Calculate the density of water. | A 200,000cm3 volume of air has a mass of 245g. Calculate the density of air. |
|
Volume = 0.635m3 \[\rho = \frac{m}{V}\] \[\rho = \frac{5000}{0.635}\] \[\rho = 7874kg/m^3\] |
Volume = 50,000cm3 = 0.05m3 \[\rho = \frac{m}{V}\] \[\rho = \frac{50}{0.05}\] \[\rho = 1000kg/m^3\] |
Volume = 200,000cm3 = 0.2m3 \[\rho = \frac{m}{V}\] \[\rho = \frac{0.245}{0.2}\] \[\rho = 1.225kg/m^3\] |
Key Stage 4
Meaning
Density is the amount of mass per unit volume of an object.
About Density
- An object with a large amount of mass in a small volume is said to have a high density.
- An object with a small amount of mass spread over a large volume is said to have a low density.
- The units of density are kg/m3.
Finding the Density
Finding The Density of a Regular Object
- Measure the mass of the cuboid using an Electronic Balance or Measuring Scale.
- Measure the length, width and height of the cuboid.
- Multiply the length, width and height to calculate the volume.
- Divide the mass by the volume of the cuboid to calculate the density.
Finding The Density of an Irregular Object
- Measure the mass of the object using an Electronic Balance or Measuring Scale.
- Fill a measuring cylinder with enough water to submerse the object.
- Take a reading of the volume of water in the Measuring Cylinder.
- Place the object in the Measuring Cylinder and ensure it is submersed.
- Take a reading of the volume of water + object in the Measuring Cylinder.
- Subtract the volume of water from the volume of water + object to find the volume of the object.
- Divide the mass by the volume of the object to calculate the density.
|
| Solids are the most dense state of matter because there are a large number of particles in a certain volume and gases are the least dense state of matter because there are a small number of particles in a the same volume. |
Density and Floating
- If an object is more dense than water it will sink.
- If an object is less dense than water it will rise through water and float on the surface.
Equation
- Density = Mass/volume
\[\rho = \frac{m}{V}\] Where:
Example Calculations
| 5000kg of Iron has a volume of 0.635m3. Calculate the density of Iron. | A 50,000cm3 container of water is full with a 50kg mass of water. Calculate the density of water. | A 200,000cm3 volume of air has a mass of 245g. Calculate the density of air. |
|
Volume = 0.635m3 \[\rho = \frac{m}{V}\] \[\rho = \frac{5000}{0.635}\] \[\rho = 7874kg/m^3\] |
Volume = 50,000cm3 = 0.05m3 \[\rho = \frac{m}{V}\] \[\rho = \frac{50}{0.05}\] \[\rho = 1000kg/m^3\] |
Volume = 200,000cm3 = 0.2m3 \[\rho = \frac{m}{V}\] \[\rho = \frac{0.245}{0.2}\] \[\rho = 1.225kg/m^3\] |