Exploring LifeCHAPTER 1 LESSON 3 – P. 27-31

Key Concepts• How did microscopes change our ideas about living things?

• What are the types of microscopes, and how do they compare?

Vocabulary• Light microscope

• Compound microscope

• Electron microscope

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.

Robert Hooke• First person to see cells and coined the term

“cell”

• 1665

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

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

Resolution

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.

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.

Characteristics of a microscope• There are 2 main types of microscopes, light microscopes and

electron microscopes. Both differ by magnification and resolution.

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

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.

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

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)

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)

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

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.