Microscopy: Magnification, Resolution & Types of Microscopes | A-level Biology | OCR, AQA, Edexcel
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- Опубліковано 15 чер 2024
- Microscopy: Magnification, Resolution & Types of Microscopes in a Snap! Unlock the full A-level Biology course at bit.ly/2TUo6w2 created by Adam Tildesley, Biology expert at SnapRevise and graduate of Cambridge University.
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The key points covered of this video include:
1. Principles of Microscopy
2. Magnification and Resolution
3. The Light Microscope
4. Laser Scanning Microscopes
Principles of Microscopy
The human eye can distinguish objects about 0.1mm apart - about the size of a human egg cell. Biologists want to study objects much smaller than this though, like bacteria and red blood cells. Eyes have limited magnification and resolution. To observe biology we need to increase our maximum magnification and resolution. We do this by using a microscope.
Magnification and Resolution
Different microscopes have different magnification and resolution. Magnification describes how many times bigger an image gets when it is put under the microscope. More powerful microscopes have higher magnification. Magnification is different from resolution. Resolution describes how much fine detail we can see in the image. It is defined as the smallest distance that two objects can be apart while still appearing as two objects. Here is a summary of magnification and resolution:
Light Microscope
Light microscopes were the first and still most common type of microscope. Light is sent from a light source through a specimen, the image of which is magnified by glass lenses. They are the most common because they are cheap, they are easy to use, they can be used to study living cells (which isn’t the case for all microscopes), Light microscopes show a 2D image of living cells, Light microscopes use visible light to create an image and this limits their resolution to 200nm and magnification to x2000.
Laser Scanning Microscopes
Laser scanning microscopes use a high power beam of light to create an image. The laser passes over each point in the specimen and creates an image over time. Laser scanning microscopes are more expensive than light microscopes but have a high resolution. They can also show specimens in 3 dimensions.
Summary
Magnification describes how many times larger an image appears
Resolution describes the smallest distance between two distinguishable points. Laser scanning microscopes have a higher resolution than light microscopes and can represent 3D specimens
Light microscopes magnify images using lenses
Light microscopes are cheap, easy to use, and can study living cells
They have a resolution of 200nm and a magnification of 2000x
Laser scanning microscopes have a higher resolution than light microscopes and can represent 3D specimens
can you do a video on calibration of eyepiece graticule and with stage micrometer aqa
yes please can he do this i'm so lost
Could u please make videos on A level chemistry too? I love the u explain things in much more deeply and in an organized way. Really helping my IBDP biology also my friends who've taken A levels
Very good, clear explanation. Thank you.
What about electron microscopes ?
great ! Thank you
This video help me sooo muchh!!
Glad it helped you! 💯
so cool , thank you
You're welcome! 🧊
What kind of microscope do I need to buy for AS/ A level Biology practical ?
I know the cover is disposable...but can i reuse it if i want?
god I hate microscopes.
I hate my life
@@maherzain434 May ALLAH give u happy life
@@shahjohn6469 jazakallah khayr 😂❤
Me too.
you probably dont care at all but does any of you know of a way to log back into an instagram account??
I somehow lost the account password. I would appreciate any help you can offer me.
What about the electron microscope and you were to brief but it was good.
when using light microscope do you start the largest or smallest distance between the lens and specimen./why??
It depends on what lens you are talking about, if you are talking about the condenser lens, then it must be focused on the specimen (at precision) so that it’s easier for the objective lens to reflect on the eyepiece lens
The ONE science voiceover that ISNT nerdy or geeky or annoying aha
The goat
What’s the resolution of a laser scanning microscope? :)
how about electron microscopes?@snap revise
well, he talks about to specific microscopes
This might help, its notes that I've written down from before:
■For very small viewing things Electron microscopes can be used. Electrons have a much *lower wavelength* than light which means they can be used to produce an image with resolution as great as *0.1nm* . Electron microscopes can have a magnification of *x500000* .
■There are different types of Electron microscopes. A Transmission Electron Microscope ( *TEM* ) producers a *2D image* of a thin sample, and has a maximum resolution of *x500000* .
■A Scanning Electron Microscope ( *SEM* ) produces a *3D image* of a sample by 'bouncing' electrons off and detecting them at multiple detectors. Maximum magnification of *x100000* .
the top information is notes i printed off a while back, I'm not sure which website it would be from. if you want to find the website just copy some of the lines and the website should be one of the first links.
*COMPARISON*
SEM:
*Advantage*
■ wide arrange of application
■ detailed 3D & tepographical imaging
■ easy to operate with proper training - user friendly
■ works fast
*Disadvantage*
■ expensive
■ large
■ area issue (houses in areas without magnetic, electric, vibration interferences)
■ maintenance
■ limited to sample analyse
■ small risk of radiation
TEM:
*Advantage*
■ most powerful magnification
■wide range of applications & used in varied fields
■images are in high quality & detail
■ able to yield info of surface features, shape, size, structure
■ easy to operate with proper training.
*Disadvantage*
■ large and expensive
■ laborious sample preparation
■ requires special training
■ requires special housing and maintenance
■ images are black and white
Light Microscope:
*Advantage*
■ cheap to buy and operate
■ small and portable
■ natural colour of specimen is observed
■ both live and dead samples
■ preparation quick and simple
■ unaffected by magnetic field
*Disadvantage*
■ magnifies max *x1500*
■ preparation may distort specimen
■ depth of field is restricted
■ has a resolution of only around 1nm
Hope that helps 😁
Excellent!!
Thank you! Cheers! 💯
which magnification of thes microscope is better TEM or SEM and why
oh dude, nice qestion
*COMPARISON*
SEM:
*Advantage*
■ wide arrange of application
■ detailed 3D & tepographical imaging
■ easy to operate with proper training - user friendly
■ works fast
*Disadvantage*
■ expensive
■ large
■ area issue (houses in areas without magnetic, electric, vibration interferences)
■ maintenance
■ limited to sample analyse
■ small risk of radiation
TEM:
*Advantage*
■ most powerful magnification
■wide range of applications & used in varied fields
■images are in high quality & detail
■ able to yield info of surface features, shape, size, structure
■ easy to operate with proper training.
*Disadvantage*
■ large and expensive
■ laborious sample preparation
■ requires special training
■ requires special housing and maintenance
■ images are black and white
Light Microscope:
*Advantage*
■ cheap to buy and operate
■ small and portable
■ natural colour of specimen is observed
■ both live and dead samples
■ preparation quick and simple
■ unaffected by magnetic field
*Disadvantage*
■ magnifies max *x1500*
■ preparation may distort specimen
■ depth of field is restricted
■ has a resolution of only around 1nm
Tem has the strongest magnification of x500000
Sem has a magnification of x100000
0 o 0 thankyou so much amazing human
Am from Bombo Army SSS, Uganda,I liked but we need more organic chemistry too or you specialised in Biology
Great
Many thanks! 😊
volume?
The diagram at 5:36 is going to confuse people- it's more-or-less upside-down relative to the typical passage of light on an actual microscope.
@Anish Lohani resolution is determined by the ability to distinguish separate things. The light microscope makes such a task easier to do.
@Anish Lohani No. Maybe these will help you understand that there is a difference between the resolution of the human eye and of a light-microscope & why magnification is another matter altogether:
courses.lumenlearning.com/ap1x94x1/chapter/magnification-and-resolution/
courses.lumenlearning.com/physics/chapter/27-6-limits-of-resolution-the-rayleigh-criterion/
@Anish Lohani Good idea
@Anish Lohani Think about it this way- an image of something observed with the naked eye is 'simply' projected onto the light-sensitive cells at the back of it. Unaided, the discernable details of the image are limited by the wavelength of visible light AND acuity of vision afforded by the retina- the cells of which are fixed in terms of size, position, number & therefore density. Naturally, they will be exposed to a greater amount of detail if said image is magnified. Consider what the pixels of a computer monitor screen are able to show while zooming into a location using Google maps- you can't distinguish between houses etc. until you zoom right in (resolving power).
its ok.but i think you were moving fast
i literally watched it on 1.5x speed because i thought he was too slow
Sir let you explain AS level biology topic by topic per video
I know some of u r here
Uhhh you missed out transmission electron microscopy and scanning electron microscopy, this channel frequently misses out important information without even mentioning the information they missed. Absolutely abysmal
The course we have uploaded on UA-cam is just a taster of the full course. We have over 600+ videos covering every spec point available on our webiste snaprevise.co.uk
@@snaprevise i cant find the video on the website. where can i find it