Microscopes

• The base of a light microscope is located at the bottom and connects to the top via an arm.
• A lamp or mirror is used as the light source in a light microscope.
• The stage of a light microscope is where the microscope slide is placed.
• The top half of a light microscope consists of three objective lenses with different magnifications such as 10 times, 20 times, and 50 times.
• The eyepiece lens in a light microscope has a fixed magnification and sits at the top where the user looks into the microscope.
• The body tube is located just above the eyepiece lens in a light microscope.
• The coarse and fine focusing knobs in a light microscope are used to help adjust the image in focus.
• Through our onion cells which remember us sitting there on the stage, we pass through one of the objective lenses, then through the eyepiece lens, and finally into our eye, looking into the eyepiece.
• The lenses spread out the light rays so that the image that we see is far larger than the actual object.
• Magnification is how many times larger the image is than the object, and if the image appeared 1000 times larger than the object, then the magnification would be times 1000.
• The equation for magnification is image size divided by object size.
• Resolution is the shortest distance between two points on an object that can still be distinguished as two separate entities.
• If two parts of an object can be apart without appearing blurred, then they have the same resolution.
• The higher the resolution of an image, the more details you'll be able to see and the less blurry it will look.
• In microscopy, the term object refers to the real object or sample that is being observed, while the term image refers to the image that is seen when looking down the microscope.
• The scale stretches from nanometers, which is the smallest unit, to micrometers, millimeters, meters, and kilometers.
• Each unit in the scale is 1,000 times bigger or smaller than the one next to it, for example, a kilometer is 1,000 times bigger than a meter and a nanometer is a thousand times smaller than a micrometer.
• To convert a particular value into a larger unit, divide the number by 1000 for each place that you want to move it up the scale.
• To convert six millimeters to meters, divide the number six by one thousand to get 0.006 meters or 6 times 10 to the minus 3 meters.
• To convert six millimeters to kilometers, divide the 0.006 by 1000 to get 0.000 kilometers or 6 times 10 to the minus 6 kilometers.
• To convert something to a smaller unit, multiply the number by 1000 for each place you want to move down the scale.
• To convert six millimeters to micrometers, multiply the six by one thousand to get six thousand micrometers which can also be written as six times ten to the three micrometers.
• The size of atoms ranges from around 0.1 to 0.5 nanometers across.
• Medium-sized molecules like glucose are about one nanometer across.
• Viruses might be 100 nanometers or so across.
• Small cells like bacteria could be a micrometer or so.
• Most animal and plant cells are in the 10 to 100 micrometer range.
• Human hair is about 100 micrometers wide.
• If you had nothing but the naked human eye, you'd better see all the way down to about 100 micrometers.
• With a light microscope, like the ones used in class, you'd better see all the way down to 500 nanometers or so.
• If you used special microscopes called electron microscopes, you would see all the way down to about 0.1 nanometers.
• A centimeter is equal to 10 millimeters and there are 100 centimeters in a meter.
• To convert from centimeters to millimeters, multiply the number by 10.
• To convert from centimeters to meters, divide the number by 100.
• To convert six millimeters to nanometers, multiply the six by one thousand again to get six million nanometers or six times 10 to the 6th nanometers.
• 340 nanometers to millimeters, divide by one thousand once to get micrometers then divide by a thousand again to get millimeters, the 340 nanometers would become 0.34 micrometers and then it would become 0.00034 millimeters.