Exploring life
Allowed people to see details of an object that they could not see before Robert Hooke- in the 1600’s used a microscope to look at cork He was the first scientist to name cells because they resemble “prison cells” He was looking at the remains of the cell wall in the cork
Anton van Leeuwenhoek- Dutch merchant Late 1600’s Made improvements to the existing microscopes Microscopes could not magnify up to 270 time the original size
Magnification of the microscope Magnification makes the object look bigger Resolution of a microscope How clearly you can see the object has to do with the resolution of the microscope
Two major types based on the source of illumination Light Electron Light Electron
Uses a light source or mirrors to enlarge an object Some light microscopes have a single lens The microscope we use is a compound microscope Two lenses 1. In the ocular 2. In the objective To find the magnification you MULTIPLY the ocular value by the objective Example: Ocular 4 X Objective 10 X So total magnification is 4 x 10 or 40 X
0.2 micrometers or two millionths of a meter Dyes maybe used to help visualize parts of the cell
Use a magnetic field to focus a beam of electrons through an object Can magnify up to 100,000 times or more (light can only magnify up to 1500 times) The resolution is 0.2 nanometers or two billionths of a meter TEMSEM
Transmission electron microscopes (TEMs) Study extremely small structures in cells Specimen needs to be in plastic and then thinly sliced Only dead specimens can be used Computer image is produced Scanning electron microscopes (SEMs) Study the objects surface Electrons bounce off the image and produce a 3 D image on the computer Can be a living specimen
Health care Laboratory to study specimens like blood Surgery like cataracts or brain surgery Determine if tissue sample has cancer or not Forensics Crime scenes- to determine body fluids and insect data Archeologists Study fossils and the material surrounding the fossil Industry Examine steel for impurities Study jewels