SCIENCE 7 (Quarter 2-Module 1): PARTS OF THE MICROSCOPE

[Music] good day grade 7 students it's another wonderful day to learn more welcome to our tv lesson for science seven quarter two module one i am teacher john jeff of faith nimr from lorenzo s sarmiento senor national high school malwa district i am very excited to bring you today's lesson about the microscope specifically their parts and functions keep watching because at the end of this lesson you are expected to enumerate the different parts of a microscope and their functions prepare yourselves as we discover more about the wonderful world of science now get your pen and paper and your self-learning modules so what are we waiting for let's begin learning the branch of science that deals with the study of life is known as biology one of the tools that is used by the scientists to study life is called a microscope with the invention of the microscope we are able to understand life even better but what is microscope a microscope is a tool that is used to see organisms or objects that are too small to be seen by the naked eye the microscope makes these small objects look bigger some of the tiny objects or organisms that can be seen using the microscope are the following plant cells animal cells and microorganisms such as bacteria the different strains of virus such as coronavirus can also be seen using a microscope scientists are using the microscope in understanding the structure of the coronavirus to develop a vaccine for coronavirus disease 2019 or covet 19. the science of investigating very tiny organisms and small objects using the microscope is called microscopy to understand how microscope works we need to be familiar with two terms magnification and resolution when we say magnification it describes how much larger an object appears when viewed observe the structure of an onion cell pointed in a red arrow as you can see it is so small if we want to see it better we can increase its magnification and as you can see the structure now looks bigger and that is magnification or the magnifying power of a microscope on the other hand resolution or the resolving power is the capacity of a microscope to distinguish small gaps between two separate points which human cannot distinguish it is used to see finer details of an object compare the two pictures which picture shows a finer detail of a plant cell correct it's picture b this means that picture a has a lower resolution and picture b has a high resolution because more details of the plant cell are visible there are different types of microscope but in this video we are going to focus on a compound microscope [Music] a compound microscope is an optical microscope that uses visible light to form an image it uses glass lenses to magnify and resolve images but why is it called a compound microscope [Music] this type of microscope is called a compound microscope because it uses two or more double convex lenses to magnify the object these two lenses can be found on the eyepiece and the objectives of the microscope a compound microscope comprises of three major parts based on their functions magnifying illuminating and the mechanical parts let us first talk about the magnifying parts of a compound microscope the magnifying parts of the microscope make the specimen looks bigger the specimen is the object or part of the object or an organism that we study or examine under the [Music] microscope the picture on the screen shows a specimen from the skin of an onion the first magnifying part is the eyepiece the eyepiece is also known as ocular lens these are the lens located at the top of the microscope this is where the viewer looks and see the magnified image of the specimen aside from this the eyepiece lens also magnifies the image of the object its standard magnification is 10 times the second magnifying parts are the objective lenses just like the ocular lens their main job is to magnify the specimen under observation these are the major lenses used for specimen visualization most schools have light microscope with three objectives others have four the typical objective lenses are the following a low power objective it has a magnification power of 10 times it is used to see the general outline of the specimen next is high power objective it has a magnification power of 40 times it is used to view structures from a larger perspective and the last one is oil immersion objective it has a magnification power of 100 times it is usually the longest objective and used to view bacteria very small protist and fungi it requires the use of special oil let us now proceed to the illuminating parts of the microscope the word illuminate means to give light therefore these are the parts of the microscope that supply and regulate light towards the specimen first we have the mirror the function of the mirror is to reflect light from an external light source up through the bottom of the stage which illuminates the specimen the light source can be in the form of natural light just like the light from the sun and an artificial light from a lamp in other microscopes an illuminator is used in place of a mirror it captures light from an external source of a low voltage of about 100 volts in short this uses electricity second is the diaphragm it is located under the stage this part controls the amount of light that reaches the specimen this is important because it provides enough light in viewing the specimen also located under the stage is the condenser this part collects and focuses the light from the mirror to the specimen let us now explore the mechanical parts of the microscope these parts are used for support and in adjusting the different parts of the microscope body tube or draw tube this tube holds the eyepiece lens and connects them to the objective lenses next is the revolving nose piece this part holds the different objective lens and facilitates the changing of objectives and this is the part that you turn to change the objective lens that you want to use [Music] the next parts are the adjusting knobs these adjusting knobs are used to focus the microscope there are two types of adjusting knobs in a microscope [Music] the bigger adjusting knob is called coarse adjusting knob it moves the body tube and low power lenses closer or farther away from the stage to view the image of the specimen the coarse adjusting knob should only be used with low power objectives it is because the mechanism of course adjustment knob produces a large vertical movement of the stage with only a partial revolution of the knob on the other hand the smaller adjusting knob is called the fine adjustment knob it is used to bring the specimen into sharp focus to show clearly the detailed parts of the specimen it is used under low power or it is used for focusing when using high power lenses unlike the coarse adjustment knob the fine adjustment knob moves lower or shorter in terms of distance than the course adjustment knob the next part is the stage it is a flat surface where the mounted slide is placed a slide is where the specimen is placed for observation a stage consists of stage clips these clips holds the specimen slide in place the next parts are arm and base the base serves as the support of the whole microscope and the arm serves as the handle of the microscope in carrying it the arm and base are connected by the inclination joint it allows the user to tilt the microscope for more comfortable viewing especially when you are in sitting position however you must only tilt the microscope when you are working with dry specimen tilting the microscope with liquid specimens can cause liquid spill and flow into the metal parts these can cause rusting which can damage the function of the microscope those are the different parts of a microscope and their specific functions to sum it up microscope is a tool that is used to see organisms that are too small to be seen by the naked eye the microscope makes the small object look bigger the parts of the microscope can be divided into three parts magnifying illuminating and mechanical parts to test your understanding about the different parts of the microscope try to label the parts of this microscope write your answer on a sheet of paper compare your answers to the answer key that is found at the end of this video i hope you learn and enjoy the lesson stay safe and always be cautious see you all next time i am teacher john and joff of eight dimer poros from lorenzo esrmiento senor national high school [Music] bye [Music] [Music] you

Channel: DDO TV Eskwela

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Length: 15min 21sec (921 seconds)

Published: Thu Feb 18 2021