2. Microscopes are used to increase the magnification and resolving power of the unaided eye MICROSCOPES

3. MAGNIFICATION: the ability of the lens to enlarge the image Total Magnification = Magnification of Objective lens x Magnification of ocular lens RESOLVING POWER: the ability to deliver a clear, sharp image by distinguishing between two objects that are close together DEFINITIONS

4. 1.SIMPLE LIGHT MICROSCOPE A single lens and light source TYPES OF MICROSCOPES

5. 2. COMPOUND LIGHT MICROSCOPE Two lenses (objective and ocular lens) and a light source TYPES OF MICROSCOPES

6. 3. TRANSMISSION ELECTRON MICROSCOPE (TEM) A beam of electrons is transmitted through a very thin specimen An image is formed from the interaction of the electrons transmitted The cells must be dead in order to view Image can be magnified up to 5 000 000 x Resolution up to 2 nm TYPES OF MICROSCOPES

7. TEM

9. 4. SCANNING ELECTRON MICROSCOPE (SEM) A sample is imaged by scanning it with a beam of electrons The electrons interact with the atoms and produce signals that will create a 3D image The specimen can be thick The image can be magnified up to 300 000 x Resolution up to 10 nm TYPES OF MICROSCOPES

10. SEM

12. Complete the following chart by placing a checkmark in the correct boxes COMPARING TEM AND SEM TEMSEM Specimen must be very thin Specimen must be dead Electrons pass through specimen Electrons scan specimen Higher magnification Higher resolution

13. Complete the following chart by placing a checkmark in the correct boxes COMPARING TEM AND SEM TEMSEM Specimen must be very thin * Specimen must be dead * Electrons pass through specimen * Electrons scan specimen * Higher magnification * Higher resolution * Produces a 3D image *