Tiêu đề GPB 121 Manual.pdf ✅

1 What is a Microscope? EXERCISE NO. 1 Study of Microscope It is an instrument that is used to see those substances and organisms, which cannot be seen with the naked eye. The basic model of a microscope contains one or more lenses that make small objects look bigger, so that the details can be viewed. Nowadays, various advanced models of microscopes are being used for different purposes. Even though there are different types of microscopes, the three basic types are optical (light), electron, and scanning probe microscopes. Microscopes are important tools for studying cellular structures. Anton van Leeuwenhoek of Holland found the simple microscope in 1673 and he is called as “father of microscopy.” Object: To get mastery of the use of microscope which is the basis to a thorough understanding of genetics. Principle: The lenses in this instrument are so adjusted that minute objects invisible to naked eyes are magnified and made visible. There are two types of microscopes in common use. 1. Simple microscope: Only one lens (or one set of lenses) is used in between the eye and object e.g. Hand lenses and dissecting microscope. 2. Compound microscope: Two or more than two lenses (or set of lenses) are used in between the eye and object and this helps in obtaining more magnification e.g.Student's microscope, Research microscope. Parts of student's microscope: 1. Eye piece (Ocular): A single set of lenses placed on the upper end of a body tube with usual magnification of 5x, 10x, 15x etc. The function of eyepiece is to magnify the object to a certain extent. 2. Body tube (Draw tube): Tube holding the eyepiece and the objective lenses at upper and lower ends respectively. It is fitted to the arm by rack and pinion arrangement for upward and downward movement. The length of the tube is fixed and is generally 160 mm. 3. Objective lens: One or more sets of lenses are fitted to the lower end of body tube with the help of revolving nosepiece. There are two objectives in student's