[Music] if you were alive 200 years ago you would have been given some very strange advice on how to avoid getting ill you might have been told to carry sweet-smelling flowers with you or avoid going to smelly places this was because at that time people didn't understand that infectious diseases were caused by microorganisms and they didn't know that because they couldn't see them microorganisms are so cold because they can only be seen using a microscope they are far too small to be seen with the naked eye in fact the invention of the light microscope opens up a whole new world to scientists the microscopic world a microscope magnifies objects and make a larger image this allows us to see objects in more detail resolving power or resolution is also a feature of microscopes resolution is the ability to distinguish two different points as being separate basically using a microscope of a high resolution means that you can increase the magnification further without the image becoming blurry the light microscopes you may use at school will have quite a low magnification and resolution but they will still enable you to view individual cells to use a microscope you place a slide containing the specimen onto the stage and secure it using the clips you first choose the lowest objective lens by turning around the nose piece this is usually times 10 magnification you then turn on the light this might be by using an electric light or moving a mirror to reflect light onto the specimen if you look down the eyepiece lens you will see the image you will probably need to use the focusing knobs to move the stage up and down until the image is clear and not blurry you must be careful when moving the stage up not to knock into the objective lens as this might break it now you can choose a higher magnification objective lens to see the specimen in more detail you might have to readjust the focus now you can clearly see the specimen you can draw it and write down the total magnification you used this is calculated by multiplying the magnification of the eyepiece lens which is normally times 10 by the magnification of the objective lens you will also need to be able to use a magnification formula magnification equals size of image divided by size of real object so if the diameter of an image of a red blood cell in a book is one centimeter and the actual diameter of a red blood cell is 0.001 centimeters then the magnification used must be one divided by zero point zero zero one equals times one thousand the microscopic world has been opened up even further due to the invention of the electron microscope these use beams of electrons to form images and have much higher magnifications and resolutions than light microscopes they have enabled scientists to study objects in much more clarity and detail from cell organelles like the nucleus and membrane to even smaller structures like individual atoms if you liked the video give it a thumbs up and don't forget to subscribe comment below if you have any questions why not check out our few school app as well until next time