The development of the microscope allowed scientists to observe microorganisms and cells, changing beliefs about disease causation. Robert Hooke and Anton van Leeuwenhoek used early microscopes to observe cells and microorganisms in the 1600s-1700s. Modern microscopes like light microscopes and electron microscopes provide higher magnification and resolution to observe living and non-living microscopic structures.

1. Exploring Life
CHAPTER 1 LESSON 3 – P. 27-31

2. Key Concepts
• How did microscopes change our ideas about living things?
• What are the types of microscopes, and how do they compare?

3. Vocabulary
• Light microscope
• Compound microscope
• Electron microscope

4. The Development of Microscopes
• The development of the microscope was crucial for
understanding disease and pathogens, the causes
of diseases.
• Between 1600-1800s many people didn’t believe in
pathogens, microbes that cause illness.
• t took almost 200 years after the Anton van
Leeuwenhoek saw the first microorganisms for the
concept of spontaneous generation to die out.

5. Robert Hooke
• First person to see cells and coined the term
“cell”
• 1665

6. Anton van Leeuwenhoek
• Dutch merchant and lens grinder
• He is called the “Father of Microbiology”
• He was able to make simple microscopes that could
magnify an object up to 270x.
• He was the first person to discover blood cells and
microorganisms.
• 1674

7. Types of Microscopes
ONE CHARACTERISTIC OF ALL MICROSCOPES IS THAT MY
MAGNIFY OBJECTS. WHAT DOES IT MEAN WHEN SOMETHING IS
MAGNIFIED?

8. Resolution

9. Resolution
• Magnification is how many times larger the object appears than its original
size.
• For example, if I am looking at a 1mm long bug that appears 2mm long under the microscope. The
magnification of the microscope is 2x.

10. Resolution
• Resolution is how
clear an object looks
under a microscope.
• For example, if you put an
ant under a microscope
that has 10x magnification
and you can’t see its legs
the resolution of that
microscope is poor.

11. Characteristics of a microscope
• There are 2 main types of microscopes, light microscopes and
electron microscopes. Both differ by magnification and resolution.

12. Light Microscopes
• Light microscopes use light and
lenses to enlarge an image of an
object.
• If a light microscope uses more than
one lens it is a compound
microscope.
• If a light microscope uses one lens, its
simple.
Total Magnification = ocular lens x objective lens

13. Light Microscopes
Light microscopes can enlarge images up to
1500 times the original size.
◦The resolution of a light microscope is about 0.2
micrometers or 2/1,000,000 of a meter.
◦This means if to points are 0.2 micrometers apart you
can see the space between them.
Light microscopes can be used to see living and
nonliving things.
◦They must be mounted on a slide.
◦Some objects must be stained such as white blood
cells.

14. Electron Microscopes Are Awesome!
Electron microscopes use a magnetic
field to focus a beam of electrons
through an object or onto an object’s
surface.
◦Can magnify up to 100,000x
◦Resolution 0.2nanometers or
2/1,000,000,000 meter
◦1,000 times better than a light microscope
The Electron
Microscope

15. TEM (transmission electron microscope)
Used to see tiny things like cell
structures.
◦Preparation is hard
◦Objects are mounted in plastic and thinly sliced
◦Only see dead organisms
◦Electrons pass through the object
and the computer makes an image
◦Cost: $250,000 (7,500,000 NT)

17. SEM (scanning electron microscope)
Used to study an objects surface
Electrons bounce off the object and a
computer produces a 3-D image
Can be used to see living things
Cost: $500,000 (15,000,000 NT)

38. Using Microscopes
Health Care
◦Surgery
◦Analyze blood, urine and
other fluids
◦Examine healthy and diseased
tissue
◦Display surgery
Other Uses
◦Forensic science to study evidence
at crime scenes
◦Identifying mold or insects from an
idea
◦Paleontologist and palynology
examining fossils
◦Industry
◦Steel factories to check for impurities
◦Jewels for scratches

39. What would you use?
1. You study the shape of different minerals.
2. You study the structures inside microorganisms.
3. You study the way a type of pond microbe moves around.
4. You are counting the number of white blood cells a person has.
5. You need to know the different structures and shapes of pollen.