What is the difference between theory and law

What is the difference between theory and law? Agenda for Wednesday Dec 14 th 1. Check seeds 2. Quiz 3. Microscope notes

What does the diaphragm do on a microscope? Agenda for Thursday Dec 15 th 1. Check seeds 2. Finish notes 3. Microscope Lab

Types of Microscopes 1. Light Microscope • use compound lenses to magnify objects. The lenses bend or refract light to make the object beneath them appear closer.

2. Stereoscope • This microscope allows for binocular (two eyes) viewing of larger specimens. • Can be used for thicker specimens or dissections • Creates a 3 D view of specimen

3. Scanning Electron Microscope - • SEMs use electrons to magnify objects up to two million times • SEM creates a 3 D view of specimen, but cannot view living specimens (process kills them)

4. Transmission Electron Microscope • also uses electrons, but instead of scanning the surface (as with SEM's) electrons are passed through very thin specimens. • TEM = "thin"

Magnification • Your microscope has 3 magnifications: Low, medium, and High. • In addition the ocular lens (eyepiece) has a magnification • The total magnification is the ocular x objective

Comparing Powers of Magnification We can see better details with higher the powers of magnification, but we cannot see as much of the image. Which of these images would be viewed at a higher power of magnification?

Focusing Specimens 1. Always start with the scanning (low) objective. A. Use the Coarse Knob to focus and then the fine adjustment knob until clear. B. Then center object 2. Switch to medium Power. A. Use the Coarse Knob to focus and then the fine adjustment knob until clear. B. Center specimen 3. Now switch to High Power. A. ONLY use the Fine Adjustment Knob to focus. DO NOT SKIP STEPS!!!! Recap 1. Scanning --> use coarse and fine knob 2. Low power --> use coarse and fine knob 3. High power --> use fine knob only

Troubleshooting Occasionally you may have trouble with working your microscope. Here are some common problems and solutions. 1. Image is too dark! Adjust the diaphragm, make sure your light is on. 2. There's a spot in my viewing field, even when I move the slide the spot stays in the same place! Your lens is dirty. Use lens paper, and only lens paper to carefully clean the objective and ocular lens. The ocular lens can be removed to clean the inside. The spot is probably a spec of dust. 3. I can't see anything under high power! Remember the steps, if you can't focus under scanning and then low power, you won't be able to focus anything under high power. Start at scanning and walk through the steps again. 4. Only half of my viewing field is lit, it looks like there's a half-moon in there! You probably don't have your objective fully clicked into place. .

How to make a wet-mount slide … 1 – Get a clean slide and coverslip from your teacher. 2 – Place ONE drop of water in the middle of the slide. Don’t use too much or the water will run off the edge and make a mess! 3 – Place the edge of the cover slip on one side of the water drop. 4 - Slowly lower the cover slip on top of the drop. Cover Slip Lower slowly

When using the high power objective, what focusing knob do you only use? Agenda for Friday Dec 16 th 1. Finish lab 2. Check seeds and lab write-up

How do you calculate total magnification? Agenda for Monday Dec 19 th 1. Measure notes 2. Measure lab Quiz tomorrow Test Thursday

Unit of Measure • • Micrometer or micron Unit of measure for microscopic images Symbol = µ 1 mm = 1000 µm

Calculate Field of View • • Clear Ruler Determine how many millimeters across Convert to micrometers 1 mm=1000μm one millimeter is the distance from the middle of one mark to the middle of the next mark.

Calculate Size of Specimen • Figure out how many will fit across the field of view (estimate) • Divide field of view length by how many fit across Example: *About 8 fit across – field of view is 800 μm – 800 μm/8 = 100 μm

• Low power = 4 mm or 4000 μm • Medium power = 1. 5 mm or 1500 μm • High power =. 5 mm or 500 μm

Lab Questions 1. a. If I measure the low power field of view to be 7 mm, how many μm is that? b. If I estimate that 9 of my specimen could fit across the field of view, how big is each one in mm, and μm? c. How big would the high power field of view be if the low power objective is 4 x and the high power is 50 x?

2 a. If the high power field of view is 425 μm, how many mm is that? b. If I estimated that 2. 5 specimens could fit across the field of view, how big is my specimen, in mm and μm? c. If each specimen is 30 μm, and 10 can fit across, how big is the field of view? d. If each specimen is 120 μm and the field of view is 630 mm, how many can fit across?

Review Questions

Qualitative or Quantitative? 1. The cup had a mass of 454 grams. 2. It is warm outside. 3. The tree is 30 feet tall. 4. The sidewalk is long. 5. The race was over quickly.

Mr. Novak noticed that his favorite pants were not as clean as they used to be. His wife told him that he should try using Clean. O detergent, a new laundry soap she found on pinterest. Mr. Novak made sure to wash one pair of pants in plain water and another pair in water with the Clean-O detergent. After washing both pairs of pants a total of three times, the pants washed in the Clean-O detergent did not appear to be any cleaner than the pants washed in plain water. What was the problem Mr. Novak wanted to investigate? Create a hypothesis. What is the independent variable? Dependent variable? What should Mr. Novak conclusion be?

You are conducting an experiment to determine if increased ultraviolet radiation from the decrease in the ozone layer is killing off frog tadpoles. After examining all of the data available in the library, you decide to go with a hypothesis that increased ultraviolet radiation from the sun is killing off the tadpoles. Group 1 involves 100 tadpoles in a five gallon container of water, which is covered by glass (knowing that the glass will filter out the ultraviolet radiation). Group 2 will be set up exactly like group 1, except that instead of being covered with glass, it is covered with an acrylic plexiglass, which will not filter out the U. V. radiation. You then place the groups outside for a period of a month, and observe the results. Results Number of tadpoles started with Number finished Group 1 Group 2 100 100 96 96 What is the independent variable? Dependent variable? What should the conclusion be?

Microscope Questions 1. When focusing a specimen, you should always start with the __________ objective. 2. When using the high power objective, only the ______ knob should be used. 3. The type of microscope used in most science classes is the _________ microscope 4. What part of the microscope can adjust the amount of light that hits the slide? _______________

5. You should carry the microscope by the ____ and the _____. 6. The objectives are attached to what part of the microscope (it can be rotated to click the lenses into place): ________________ 7. You should always store you microscope with the ________ objective in place. 8. A microscope has an ocular objective of 10 x and a high power objective of 50 x. What is this microscope's total magnification? ______