Investigation 2: Introduction to the Microscope

At the end of Investigation 2 you will be able to: Identify the parts of the microscope and describe proper usage. Apply knowledge of focal plane and field of view to observe and draw microscopic specimens.

Investigation 2 - Part 1 Meet the Microscope

Review and Anticipation The results of the investigation of the five materials indicated that three of them were alive—they were organisms. Two of the organisms were so small that they were difficult or impossible to see. In order to take a closer look at the organisms a special tool is needed: the microscope. Review and Anticipation

Students, “Meet Mr. Microscope.” Use lab page 7: Read using comprehension strategies. Discuss and review. Transport, care, and parts of the microscope Label the parts of the microscope You will be responsible for knowing the information and following the rules in the article when you use a microscope. If procedures are not followed, a great deal of damage may be caused. Students, “Meet Mr. Microscope.”

NOTE: Another image of a labeled microscope can be found in the Resources Book on page 3 (as seen on this slide)

The slides are glass and must be handled with care. Water and stain should only be used as directed. Lens paper truly is for the lenses ONLY. Do not use on the slides. Blotter paper is used with slides. The kit must be restocked and organized at the end of each class. The Microscope Kits…

Preparing a dry mount Place the material to be observed at the center of a slide. 2. Place another slide on top of the material and hold it flat. 3. Handling the dry mount by the edges only, place it on the microscope stage. 4. Use only the low (4x) and medium (10x) objective lenses to view the dry mount.

Managing Mr. Microscope Prepare and observe dry mounts of the letter e. Complete 1-3 on page 9 of your lab notebook. What you see when you look through the eyepiece of a microscope is called the field of view. What shape is in the field of view in your microscope? What is the relationship between the orientation of the object on the stage and the appearance of the image in the field of view? Use the color photo and a feather to respond to 4-6 on page 9. Check your responses with Virtual Microscope. Make sure you are accurate. Emphasize that this should be a lower case letter e and it should be facing them when they view it on the stage with their naked eye

Investigation 2 - Part 2 Exploring the Microworld

Yesterday, we looked at the microscopic image of the letter e and discovered some of the relationships between an object and its image. However, we didn’t figure out how big the e really is. It looks huge in the microscope, but in reality it is quite small. How can we figure out how big something is by looking in the microscope? Review and Anticipate

Try to figure out what the diameter of the 4x objective lens field of view is using your microscope kits! What is the distance between the lines on the ruler? Use whole numbers. If you saw 5 lines, how long would that be? Microscope challenge!

Discussion Questions The field of view is about 4 mm under low power. What is the field of view in your microscope when you are using the 4X objective? Can you estimate the diameter of the letter e you observed yesterday? The field of view is about 4 mm under low power. Discussion Questions The letter e was about 2 mm.

What do you think will happen to the object in the field of view if you use the 10x objective lens? It will become smaller. Question to discuss…

Magnify means “make bigger Magnify means “make bigger.” The numbers on microscope lenses tell you how much they magnify the image of the object you are looking at. The eyepiece has 10x written on it. This means it magnifies things ten times—things look 10 times bigger when viewed through the eyepiece alone. The magnification of a lens is also referred to as its power. The objective lenses have different numbers on them too. To determine the total magnification of an objective lens and the eyepiece working together, you multiply the magnifications together. Magnification For instance, when you use the 10x eyepiece with the 4x objective lens, the product is 40, so the object looks 10 times 4, or 40 times bigger.

Take a piece of netting from the microscope kit and put it on a piece of white paper. Look closely at the netting. It is made of little squares. How far is it across one of the little squares? The squares are about 1mm or a little more in width! Please record this in your lab notebook on page 11. Measurements

Preparing a Wet Mount Place a piece of nylon netting on the slide. Add 2 or 3 drops of water. Place the ruler on top of the netting so that the hatch marks run down the center of the slide. Add another drop of water on top of the ruler. Add a coverslip and use the blotter paper to clean up any excess water. Preparing a Wet Mount

Microscopic measuring Complete the three parts on lab page 11. Make sure you follow each step precisely. Estimate the width of the netting squares to the nearest 0.1mm. Draw exactly what you observe. Microscopic measuring

Discussing Magnification How big are the squares on the nylon netting? About 1 mm What is the magnification when you use the 4x objective lens? 40X How wide is the 4x objective lens field of view? About 4 mm.

Discussing Magnification What is the magnification when you use the 10x objective lens? 100X What about the 10x objective lens field of view? 1.8mm

Discussing Magnification What is the magnification when you use the 40x objective lens? 400x What about the 40x objective lens field of view? 0.4mm

Discussing Magnification What is the relationship between magnification and the diameter of the field of view? The greater the magnification, the smaller the field of view.

We have been using the microscopes to look at materials that are flat like paper and netting. It is pretty easy to get these materials in focus. Sometimes, however, microscopes are used to look at thicker materials. Let’s find out what new factors come into play when we use the microscope to focus in on three dimensional materials. 3D View

RIBBON SLIDE PREPARATION Wet mount three different- colored samples of ribbon on the slide layering them on top of each other. Complete lab page 12, in order, exactly to directions.

The lens system in a microscope is designed to focus at one distance from the end of the lens. If an object is not exactly at this distance, it is out of focus. The distance at which a microscope lens system focuses is called the focal plane. Things that fall precise and limited distance from the lens are in focus; things above or below the focal plane are out of focus. Focal Plane

Clean Up Dry all materials using blotting methods Replenish and organize tray and all materials Ensure your labs are in your binder in correct location Clean Up

Investigation 2 - Part 3 Microscopic Life

Microscopic life Do the brine shrimp do all of the things listed on the board? Can you observe them doing these things? How could we observe them more closely to get more evidence?

Begin by reading the entirety of page 13 Begin by reading the entirety of page 13. Auditor gather all materials: microscopes microscope kits vial holders small flashlights LAB PAGE 13 At this time, shine your flashlight on the shrimp culture as well.

SCIENCE JOURNAL yes no water food waste response reproduction growth Check what you observe and do not observe. yes no water food waste response reproduction growth gas exchange

The yeast you will put in with your brine shrimp has been mixed with a red dye called Congo red. It stains the yeast red so it will be easier to see. You will place one small drop on the slide with the brine shrimp. Observe the interaction at 40X and then 100X. Feeding the shrimp

1. Observe the brine shrimp using the flashlight. 2 1. Observe the brine shrimp using the flashlight. 2. Prepare the brine shrimp wet mount with NO COVER. 3. Observe 4. Add 1 drop of yeast 5. Observe Prepare a shrimp slide

Be prepared to share your findings Clean up & replenish Be prepared to share your findings

Signs of Life How did the brine shrimp and yeast interact? Is the feeding behavior evidence of life? What did the shrimp do when you shined the light on them? Did you see any other evidence of life? Signs of Life Students should share that they saw the shrimp eating and responding to their environment. They may have also noticed them eliminating waste, notice that they have grown and needed salt water to hatch. They also know that they hatched from eggs, which suggests they reproduce.

Review chart Are the shrimp alive according to our Characteristic of Life chart? Should we add to or change our poster? We will need to maintain the brine shrimp. If you are interested in the job, please fill out an application. Interviews will be scheduled and compensation discussed then. Debrief

Write a six question summary of the brine shrimp activity. Write two cinquain poems. Microscope Brine shrimp Be prepared to share your summary and poems. Summary Activities