A form of energy that travels in waves These waves are a form of electromagnetic radiation. Light is not the only form of electromagnetic radiation.

LIGHT, MICROSCOPES, AND THE HUMAN EYE

WHAT IS LIGHT?

A form of energy that travels in waves These waves are a form of

electromagnetic radiation. Light is not the only form of electromagnetic radiation.

THE ELECTROMAGNETIC SPECTRUM

COLOR

You may have noticed that color takes up a small portion of the electromagnetic spectrum.

HOW DOES LIGHT CHANGE AS IT MOVES THROUGH A SUBSTANCE?

1. Reflection (like the text above)2. Refraction3. Absorption4. Diffraction (you will not need to

remember this, but will see it in more advanced websites)

LIGHT CHANGES AS IT MOVES THROUGH SUBSTANCES

Absorption

Refraction

Reflection

MATERIAL AND LIGHT

Opaque A substance that blocks all light from traveling

through Light is reflected or absorbed

Transparent Any substance that allows light to easily pass

through without being scattered. Transluscent

Any substance that scatters light as it passes through

THE COMPOUND MICROSCOPE

Eyepiece or OcularBody Tube

Arm

Coarse Adjustment

Fine Adjustment

Nosepiece

Objective Lens

Stage

Diaphragm

Base

Light Source

SIMPLE COMPOUND 1 lens Example:

Magnifying Glass Magnification

Just the one lens

2 lenses Example: Compound

Microscope Magnification

cular

bjective Multiple for total

magnification = 50x

10x

10x

5xX

WHAT YOU SHOULD NEVER DO WITH A MICROSCOPE

Carry it with one hand. Move the ocular to show someone

something. Move the microscope to show someone

something Use the coarse adjustment in high power (will

crack the slide)

STEPS TO USING A MICROSCOPE

1. Place the specimen on a slide.

2. Start with the low power objective (red)

3. Place the slide over the hole of the stage (where light comes through), raise the stage as high as it can go using the coarse adjustment (large knob)

4. Look into the ocular lens (eyepiece) as you move the coarse adjustment to focus the specimen.

5. Use the fine adjustment to focus more precisely on the specimen.

6. If using the higher power (yellow), just move the objective lens into place. Your specimen should be in view. Again use the fine adjustment knob to focus.

WET MOUNT

Place 1 drop of water on the slide Place your specimen on the drop of water Place another drop of water on top of the

specimen Slowly lower the coverslip over the

specimen on a 45 degree angle (to prevent air bubbles)

Do not bend the cover slip, or push down on it.

STAINING A SLIDE

1. Prepare a wet mount.2. Rip off a piece of small paper towel with a

flat edge (if it doesn’t have a flat edge, fold it over to create one)

3. Place a drop of stain along one edge of the cover slip (lets say the left edge)

4. Place the paper towel along the other edge (the right edge) so that it begins to draw the stain across the slide.

PLEASE NOTE

1. Most of the information was provided with guided notes throughout this unit.