Compound Microscope Lab

For this experiment, we wanted to see things that cannot be seen with the naked eye, namely, things that are smaller than 0.1 millimeters. The image differs from what we see with our normal vision because, first, it can display things that we never seen before, and second, it reflects the item shown across the y axis, or, in a more casual sense, horizontally. When we look at it normally, we can usually capture the entire image because we see the whole surrounding. But when we look through the microscope, not all of the object may be in focus because as the resolution gets bigger, the field of view becomes smaller, therefore excluding parts of it. This is because the magnification and the field of view is inversely proportional, and in mathematical terms, magnification*field of view= a set number. The diameter of the low powered view is 500 micrometers. Through microscopes, the normal things become really creepy, like Mario's hair over here:

Here are our steps:

Cut a lower case o from a piece of newspaper. Place it right side up on a clean slide. With a dropping pipette, place one drop of water on the letter. This type of slide is called a wet mount. 

Wait until the paper is soaked before adding a coverslip. Hold the coverslip at about a 45% angle to the slide, and slowly lower it.

Place the slide on the microscope stage, and clamp it down. Move the slide so the letter is in the middle of the hole in the stage. Use the coarse-adjustment knob to lower the low-power objective to the lowest position.

Look through the eyepiece, and use the coarse- adjustment knob to raise the objective slowly until the letter o is in view. Use the fine- adjustment knob to sharpen the focus. Position the diaphragm for the best light. Compare the way the letter looks through the microscope with the way it looks to the naked eye.

To determine how greatly magnified the view is, multiply the number inscribed on the eyepiece by the number on the objective being used.

Follow the same procedure with a lowercase c. In your logbook, describe how the letter looks when viewed through a microscope.

Make a wet mount of the letter e or the letter r. Describe how the letter looks when viewed through the microscope. What new information (not revealed by the letter c) is revealed by the e or r?

Look through the eyepiece at the letter as you use your thumbs and forefingers to move the slide away from you. Which way does your view of the letter move? Move the slide to the right. In which direction does the image move?

Make a pencil sketch of the letter as you see it under the microscope. Label the changes in image and movement that occur under the microscope.

Make a wet mount of two different-colored hairs, one light and one dark. Cross one hair over the other. Position the slide so that the hairs cross in the center of the field. Sketch the hairs under low power; then go to Part D.

With the crossed hairs centered under low power, adjust the diaphragm for the best light.

Turn the high-power objective into viewing position. Do not change the focus.

Sharpen the focus with the fine-adjustment knob only. Do not focus under high power with the coarse-adjustment knob.

 Readjust the diaphragm to get the best light. If you are not successful in finding the object under high power the first time, return to step 20 and repeat the whole procedure carefully.

Using the fine-adjustment knob, focus on the hairs at the point where they cross. Can you see both hairs sharply at the same focus level? How can you use the fine-adjustment knob to determine which hair crosses over the other? Sketch the hairs under high power.

Remove the wet mount of the hairs, and replace it with the prepared slide of the colored threads. The prepared slide contains three colored threads that overlap in a specific order.

Focus the threads under low power, and adjust the diaphragm for best light.

Turn the high-power objective into viewing position. Do not change the focus.

Sharpen the focus with the fine-adjustment knob only.

Readjust the diaphragm to get the best light. If you are not successful in finding the threads under high power, repeat the procedure.

Using the fine-adjustment knob, focus on an area where the threads overlap. Use the fine- adjustment knob to determine the order in which the colored threads lie on the slide.

We deduced that the order of the overlapping threads were first green under everything, then red and black. Since red and black do not intersect in our picture, we could not determine which one was above the other, but we know that green is on the bottom.

The diameter of the high powered view is very small. Calculating it is:

400/40=A so A is 10. Then divide 500 by A to get 50 micrometers. Unfortunately, 400x magnification was ridiculously small that we could barely see anything, Si we did not use it in the pictures. Rather 40 x is sufficient, as a human hair is about 100 micrometers, roughly 0.1 mm, just in or below our sight range.

Through this experiment I learned how to care for microscopes, and how to use it and its specific parts. It also taught me that a in the microscopic world, something little can go a long way through light refraction.

Strawberry DNA Extraction lab

The purpose of the experiment is to extract the DNA from the strawberries by mashing them after putting them in a plastic bag with an extraction buffer. Some of our key findings were the the white gooey substance on top after the procedure. The significance of this experiment is to know how to extract the DNA from the strawberries and to find out which part of the solution is the DNA. Our major conclusions were that the white substance on top was the DNA.

The problem is that we are trying to find the DNA in strawberries. It was carried out because we had all the materials in hand and we should know what the DNA in strawberries look like. DNA all started with the Swiss physician Friedrich Miescher, who discovered it in 1869 and has left humanity wondering about it for generations after. The general method to approach it is to mash it and use an extraction buffer, which we are doing now. The expected results are that the DNA will float on top and be isolated from the strawberry by the alcohol.

The materials are: zip lock plastic bag, 1 strawberry, 10ml DNA extraction buffer, 2” x 2” cheesecloth (gauze) square funnel, ice cold alcohol, plastic transfer pipette, test tube, and wooden splint .

This experiment consists of the following steps:

1. add 5 ml of liquid dish washing detergent to a 100 ml beaker

2. now, add 0.75 g of salt to the same beaker

3. finally, add 45 ml of distilled water

4. rinse the strawberry with water from the tap and remove anything green (i.e. the stem and sepals

5. place the rinsed strawberry into a zip lock plastic bag and add 10 ml of the extraction buffer. carefully squeeze and seal the bag tightly, making sure any air does not remain in the bag

6. with your fingers, carefully crush or mash the strawberry against the lab table for about 1 minute 

7. place the funnel lined with the cheesecloth (gauze) square into the test tube

8. carefully pour the contents of the plastic bag (i.e. the mashed up strawberry and

extraction buffer mixture) into the gauze and filter the mixture into the test tube through the gauze

9. Fill the test tube with this mixture until it is about 1/4 filled

10. layer an equal volume of ice cold alcohol on top of the strawberry solution in the test tube using the plastic transport pipette

11. observe what happens at the interface of the alcohol and strawberry solution when you twirl a long wooden splint through the interface. keep the tube at eye level and DO NOT SHAKE it. 

In our results, we found the DNA. It is the white substance on top of the alcohol.

In the second picture as follows, we show the DNA rising from the strawberry.