BELLWORK

WHY DO SCIENTISTS USE MICROSCOPES?

MICROSCOPES

TARGET #9- I CAN DESCRIBE THE COMPOUND LIGHT MICROSCOPE

• Microscopes are tools that extend our vision by making objects like cells, and atoms visible•Compound Light Microscope•Shines light through a specimen and has two lenses to magnify an image•Specimens must be mounted on a slide•Specimen must be thin enough for light to pass through

TARGET #10- I CAN DESCRIBE THE 4 BASIC PARTS OF A LIGHT MICROSCOPE• There are 4 major parts of a compound light

microscope• Eyepiece• Also known as the ocular lens• Magnifies the image 10 times (10x)

• Objective Lens• Light passes through the specimen and then through the

objective lens• Located directly above the specimen• Enlarges the image of the specimen

• Stage• A platform that supports a slide holding the specimen

• Light source• Either a light bulb or light reflected

1. Ocular lens(Eyepiece)2. Body Tube

3. Nosepiece

4. OBJECTIVE LENSES

5. STAGE CLIPS

6. DIAPHRAGM

7. LIGHT SOURCE

8. BASE

9. FINE ADJUSTMENT KNOB

10.COARSE ADJUSTMENT KNOB

11.STAGE

12.ARM

Target #11- I can label all the parts of a light microscope

• Microscopes vary in magnification abilities

• Magnification: the apparent increase of an objects size

• The degree that an object is magnified in a microscope is called the power of magnification

• To compute the power of magnification of a microscope, multiply the magnification of the strongest objective lens by the power of the ocular lens• Ex: if the strongest

objective lens is 100x magnification, multiply by the objective lens which is usually 10x, then the total magnification is 1,000x

TARGET #12- I CAN EXPLAIN HOW TO CALCULATE THE POWER OF MAGNIFICATION

On a light microscope an objective lens magnifies the view of some pond water 25 times, and the ocular lens magnifies it 10 time further. What is the final magnification of the image?

CHECKING FOR UNDERSTANDING

TARGET #13- I CAN DESCRIBE ELECTRON MICROSCOPES • To examine specimens in more detail, scientists

commonly use an electron microscope• Electron microscopes use a beam of electrons to produce an enhanced image of the specimen•More powerful in magnification and resolution than light microscopes• Images are produced in black and white, but are usually colorized to show detail via computer•Specimens are not living ones• Two types• Scanning electron microscope• Transmission electron microscope