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==Key Stage 3==
 
==Key Stage 3==
 
===Meaning===
 
===Meaning===
−
[[Diffusion]] is when [[particles]] spread from a region of high [[concentration]] to a region of low [[concentration]].
+
[[Diffusion]] is when [[particle]]s spread from a region of high [[concentration]] to a region of low [[concentration]].
  
 
===About Diffusion===
 
===About Diffusion===
−
: [[Diffusion]] can only happen in a [[fluid]] which means a [[liquid]] or a [[gas]] because the [[particle]]s can move past each other.
+
: [[Diffusion]] can only happen in a [[fluid]] (a [[liquid]] or a [[gas]]) because the [[particle]]s can move past each other.
 
: [[Diffusion]] cannot happen in a [[solid]] because the [[particle]]s are held in fixed positions.
 
: [[Diffusion]] cannot happen in a [[solid]] because the [[particle]]s are held in fixed positions.
−
: In [[diffusion]] the particles always spread from a high [[concentration]] where there is lots of the substance, to a low [[concentration]] where there is less of the substance.
+
: In [[diffusion]] the [[particle]]s always spread from a high [[concentration]] (where there are lots of the [[particle]]s, to a low [[concentration]] (where there are less of the [[particle]]s).
−
: [[Diffusion]] stops when all [[substance]]s are spread out equally and there is no longer a [[Concentration Gradient|concentration gradient]].
 
  
 
{| class="wikitable"
 
{| class="wikitable"
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==Key Stage 4==
 
==Key Stage 4==
 
===Meaning===
 
===Meaning===
−
'''[[Diffusion]] is when [[substance]]s spread from a high [[concentration]] to a low [[concentration]] along the [[Concentration Gradient|concentration gradient]].
+
[[Diffusion]] is when [[particle]]s spread from a region of high [[concentration]] to a region of low [[concentration]] along a [[Concentration Gradient|concentration gradient]].
 +
 
 +
===About Diffusion===
 +
: [[Diffusion]] can only happen in a [[fluid]] (a [[liquid]] or a [[gas]]) because the [[particle]]s can move past each other.
 +
: [[Diffusion]] cannot happen in a [[solid]] because the [[particle]]s are held in fixed positions.
 +
: In [[diffusion]] the [[particle]]s always follow the [[Concentration Gradient|concentration gradient]] spreading from a high [[concentration]] (where there is lots of the [[particle]]s), to a low [[concentration]] (where there are less of the [[particle]]s).
 +
: [[Diffusion]] stops when all [[substance]]s are spread out equally and there is no longer a [[Concentration Gradient|concentration gradient]].
 +
 
 +
{| class="wikitable"
 +
|-
 +
|[[File:Diffusion.png|center|600px]]
 +
|-
 +
| style="height:20px; width:600px; text-align:center;" |This [[diagram]] shows a high [[concentration]] of blue [[particle]]s on the left separated from the red [[particle]]s by a barrier. When the barrier is removed the blue [[particle]]s [[Diffusion|diffuse]] to the area of lower [[concentration]] on the right. [[Diffusion]] continues until all [[particle]]s are equally spread.
 +
|}
 +
 
 +
{| class="wikitable"
 +
|-
 +
|[[File:Diffusion.gif|center]]
 +
|-
 +
| style="height:20px; width:600px; text-align:center;" |This animation shows a high [[concentration]] of red [[particle]]s initially at the top. When [[diffusion]] begins the red [[particle]]s spread to the area of lower [[concentration]] at the bottom. [[Diffusion]] continues until all [[particle]]s are equally spread.
 +
|}
 +
 
 +
===References===
 +
====AQA====
  
−
===About Diffusion across a Membrane===
+
:[https://www.amazon.co.uk/gp/product/1782945954/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945954&linkCode=as2&tag=nrjc-21&linkId=100574c08fbbb64318256eb79ed61a76 ''Diffusion pages 51-53, GCSE Biology, CGP, AQA '']
−
: [[Diffusion]] in [[Cell (Biology)|cells]] is a passive process which means it does not require [[energy]] to take place.
+
:[https://www.amazon.co.uk/gp/product/0198359373/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359373&linkCode=as2&tag=nrjc-21&linkId=952a73bbb09d222ecc4b50d200679849 ''Diffusion, pages 14-15, 61, 188-189, GCSE Biology; Third Edition, Oxford University Press, AQA '']
−
: When [[Cell (Biology)|cells]] are surrounded by a high [[concentration]] of a [[nutrient]] then the [[nutrient]] will [[Diffusion|diffuse]] through the [[Cell Membrane|cell membrane]] and into the [[Cell (Biology)|cells]].
+
:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe09843 ''Diffusion, pages 17, 20, 21, GCSE Combined Science; The Revision Guide, CGP, AQA '']
−
: When a [[Cell (Biology)|cell]] has filled with a large number of waste [[chemical]]s they will [[Diffusion|diffuse]] through the [[Cell Membrane|cell membrane]] out of the [[Cell (Biology)|cell]].
+
:[https://www.amazon.co.uk/gp/product/1782945563/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945563&linkCode=as2&tag=nrjc-21&linkId=9a1d023a374038e6072f33c4f3cf808b ''Diffusion, pages 20, 21, 23-25, GCSE Biology; The Revision Guide, CGP, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/0008158754/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158754&linkCode=as2&tag=nrjc-21&linkId=27ad53b0283feeff7fc5ae04a9e205f221 ''Diffusion, pages 44-5, 55, 68-9, 86-7. 92, 94-5, 101, 106-7, 113, 117, 204, GCSE Biology; Student Book, Collins, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/1782946381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946381&linkCode=as2&tag=nrjc-21&linkId=5ec5fc3f6429e30c1d9ab9bca2bccf93 ''Diffusion, pages 45-47, GCSE Combined Science Trilogy; Biology, CGP, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/1471851338/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851338&linkCode=as2&tag=nrjc-21&linkId=425855d5890466e47189e1c21b67a1ea ''Diffusion, pages 5, 28, 29-33, GCSE Biology, Hodder, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Diffusion, pages 5, 29, GCSE Combined Science Trilogy 1, Hodder, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Diffusion; in other organisms, pages 31-2, GCSE Combined Science Trilogy 1, Hodder, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Diffusion; in the lungs, page 30, GCSE Combined Science Trilogy 1, Hodder, AQA '']
 +
:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Diffusion; influencing factors, pages 32-3, GCSE Combined Science Trilogy 1, Hodder, AQA '']
  
−
===Factors Affecting Diffusion across a Membrane===
+
====Edexcel====
−
*[[Surface Area]] - The larger the [[Surface Area|surface area]] the more quickly [[diffusion]] can take place across the [[membrane]].
 
−
*Thickness - The thinner the [[membrane]] the more quickly [[diffusion]] can take place across the [[membrane]].
 
−
*[[Concentration Gradient]] - The greater the difference between the [[concentration]] on each side of the [[membrane]] the more quickly [[diffusion]] can take place across the [[membrane]].
 
  
−
===Adaptations for Diffusion===
+
:[https://www.amazon.co.uk/gp/product/1782948120/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948120&linkCode=as2&tag=nrjc-21&linkId=dedef775c6a43dbb0a609441525adac0 ''Diffusion, factors affecting rate, page 258, GCSE Biology, CGP, Edexcel '']
−
: The [[lung]]s and [[Small Intestine|small intestine]] are specially [[Adaptation|adapted]] exchange surfaces that maximise the rate of [[diffusion]].
+
:[https://www.amazon.co.uk/gp/product/1782945741/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945741&linkCode=as2&tag=nrjc-21&linkId=30da4f2178da182547b62a7329d13b57 ''Diffusion, page 18, GCSE Combined Science; The Revision Guide, CGP, Edexcel '']
−
====Lungs====
+
:[https://www.amazon.co.uk/gp/product/1782946748/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946748&linkCode=as2&tag=nrjc-21&linkId=a4f0348fc37d0ba1bb52d27f8679581f ''Diffusion, page 21, GCSE Biology; The Revision Guide, CGP, Edexcel '']
−
The [[lung]]s must be able to [[Absorb (Biology)|absorb]] [[Oxygen]] into the [[blood]] and release [[Carbon Dioxide]] from the [[blood]] back into the [[lung]]s.
+
:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Diffusion, pages 20, 92-93, 112, GCSE Combined Science, Pearson Edexcel '']
−
: The [[lung]]s are [[Adaptation|adapted]] with thousands of [[alveoli]] which increase the surface area of the [[lung]]s.
+
:[https://www.amazon.co.uk/gp/product/1292120207/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120207&linkCode=as2&tag=nrjc-21&linkId=22455ff53961978667722edaa64c0be5 ''Diffusion, pages 24, 130-131, 162, GCSE Biology, Pearson, Edexcel '']
−
: The walls of the [[alveoli]] separating the [[air]] from the [[blood]] are very thin.
+
:[https://www.amazon.co.uk/gp/product/1782948120/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948120&linkCode=as2&tag=nrjc-21&linkId=dedef775c6a43dbb0a609441525adac0 ''Diffusion, pages 48, 49, GCSE Biology, CGP, Edexcel '']
−
: The [[blood]] supply to the [[lung]]s is very good to constantly supply [[blood]] with little [[Oxygen]] and a lot of [[Carbon Dioxide]] keeping a high [[Concentration Gradient|concentration gradient]].
+
:[https://www.amazon.co.uk/gp/product/1782946748/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946748&linkCode=as2&tag=nrjc-21&linkId=a4f0348fc37d0ba1bb52d27f8679581f ''Diffusion; factors affecting rate, page 88, GCSE Biology; The Revision Guide, CGP, Edexcel '']
 +
:[https://www.amazon.co.uk/gp/product/1292120207/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120207&linkCode=as2&tag=nrjc-21&linkId=22455ff53961978667722edaa64c0be5 ''Diffusion; factors affecting, pages 164-165, GCSE Biology, Pearson, Edexcel '']
  
−
====Small Intestine====
+
====OCR====
−
: The [[Small Intestine]] is long and folded to increase the [[Surface Area|surface area]].
+
:[https://www.amazon.co.uk/gp/product/0198359829/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359829&linkCode=as2&tag=nrjc-21&linkId=90e8d7b4f039d53035238fa0320fe00b ''Diffusion, page 123, Gateway GCSE Chemistry, Oxford, OCR  '']
−
: The [[Small Intestine]] has structures called [[Villi]] which are extra folds in the surface to increase the [[Surface Area|surface area]].
+
:[https://www.amazon.co.uk/gp/product/1782945695/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945695&linkCode=as2&tag=nrjc-21&linkId=ceafcc80bcad6b6754ee97a0c7ceea53 ''Diffusion, page 25, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR  '']
−
: The [[Cell (Biology)|cells]] on the [[villi]] have [[microvilli]] which are folds on the [[Cell Membrane|cell membrane]] to increase the [[Surface Area|surface area]].
+
:[https://www.amazon.co.uk/gp/product/1782945660/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945660&linkCode=as2&tag=nrjc-21&linkId=83aa4500ad7759e7f401a1c5ba5df758 ''Diffusion, pages 30, 33, Gateway GCSE Biology; The Revision Guide, CGP, OCR '']
−
: : The walls of the [[villi]] separating the food from the [[blood]] are very thin.
+
:[https://www.amazon.co.uk/gp/product/0198359810/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359810&linkCode=as2&tag=nrjc-21&linkId=d768d99f1a06f7c12fab40e5aef85a55 ''Diffusion, pages 58-59, 72-73, Gateway GCSE Biology, Oxford, OCR  '']
−
: The [[blood]] supply to the [[villi]]s is very good to constantly supply [[blood]] with little [[nutrients]] keeping a high [[Concentration Gradient|concentration gradient]] between the food and the [[blood]].
 

Latest revision as of 15:38, 4 December 2019

Key Stage 3

Meaning

Diffusion is when particles spread from a region of high concentration to a region of low concentration.

About Diffusion

Diffusion can only happen in a fluid (a liquid or a gas) because the particles can move past each other.
Diffusion cannot happen in a solid because the particles are held in fixed positions.
In diffusion the particles always spread from a high concentration (where there are lots of the particles, to a low concentration (where there are less of the particles).
Diffusion.png
This diagram shows a high concentration of blue particles on the left separated from the red particles by a barrier. When the barrier is removed the blue particles diffuse to the area of lower concentration on the right. Diffusion continues until all particles are equally spread.
Diffusion.gif
This animation shows a high concentration of red particles initially at the top. When diffusion begins the red particles spread to the area of lower concentration at the bottom. Diffusion continues until all particles are equally spread.

Key Stage 4

Meaning

Diffusion is when particles spread from a region of high concentration to a region of low concentration along a concentration gradient.

About Diffusion

Diffusion can only happen in a fluid (a liquid or a gas) because the particles can move past each other.
Diffusion cannot happen in a solid because the particles are held in fixed positions.
In diffusion the particles always follow the concentration gradient spreading from a high concentration (where there is lots of the particles), to a low concentration (where there are less of the particles).
Diffusion stops when all substances are spread out equally and there is no longer a concentration gradient.
Diffusion.png
This diagram shows a high concentration of blue particles on the left separated from the red particles by a barrier. When the barrier is removed the blue particles diffuse to the area of lower concentration on the right. Diffusion continues until all particles are equally spread.
Diffusion.gif
This animation shows a high concentration of red particles initially at the top. When diffusion begins the red particles spread to the area of lower concentration at the bottom. Diffusion continues until all particles are equally spread.

References

AQA

Diffusion pages 51-53, GCSE Biology, CGP, AQA
Diffusion, pages 14-15, 61, 188-189, GCSE Biology; Third Edition, Oxford University Press, AQA
Diffusion, pages 17, 20, 21, GCSE Combined Science; The Revision Guide, CGP, AQA
Diffusion, pages 20, 21, 23-25, GCSE Biology; The Revision Guide, CGP, AQA
Diffusion, pages 44-5, 55, 68-9, 86-7. 92, 94-5, 101, 106-7, 113, 117, 204, GCSE Biology; Student Book, Collins, AQA
Diffusion, pages 45-47, GCSE Combined Science Trilogy; Biology, CGP, AQA
Diffusion, pages 5, 28, 29-33, GCSE Biology, Hodder, AQA
Diffusion, pages 5, 29, GCSE Combined Science Trilogy 1, Hodder, AQA
Diffusion; in other organisms, pages 31-2, GCSE Combined Science Trilogy 1, Hodder, AQA
Diffusion; in the lungs, page 30, GCSE Combined Science Trilogy 1, Hodder, AQA
Diffusion; influencing factors, pages 32-3, GCSE Combined Science Trilogy 1, Hodder, AQA

Edexcel

Diffusion, factors affecting rate, page 258, GCSE Biology, CGP, Edexcel
Diffusion, page 18, GCSE Combined Science; The Revision Guide, CGP, Edexcel
Diffusion, page 21, GCSE Biology; The Revision Guide, CGP, Edexcel
Diffusion, pages 20, 92-93, 112, GCSE Combined Science, Pearson Edexcel
Diffusion, pages 24, 130-131, 162, GCSE Biology, Pearson, Edexcel
Diffusion, pages 48, 49, GCSE Biology, CGP, Edexcel
Diffusion; factors affecting rate, page 88, GCSE Biology; The Revision Guide, CGP, Edexcel
Diffusion; factors affecting, pages 164-165, GCSE Biology, Pearson, Edexcel

OCR

Diffusion, page 123, Gateway GCSE Chemistry, Oxford, OCR
Diffusion, page 25, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Diffusion, pages 30, 33, Gateway GCSE Biology; The Revision Guide, CGP, OCR
Diffusion, pages 58-59, 72-73, Gateway GCSE Biology, Oxford, OCR
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