Unit Two: Unit Two: Microscope and LightMicroscope and Light

MicroscopeMicroscope

What is What is Magnification?Magnification?

A larger than life A larger than life imageimage

What tools can you use to What tools can you use to magnify something?magnify something?

MicroscopeMicroscope

Who is Anton Van Who is Anton Van Leewenhoek?Leewenhoek?

One of the first to One of the first to discover discover microscopic microscopic organismsorganisms

He was one of the He was one of the first to use a first to use a microscope to view microscope to view living cells and living cells and small organismssmall organisms

Anton Van LeewenhoekAnton Van Leewenhoek

What are What are animacules?animacules?

Organisms he saw Organisms he saw in the pond waterin the pond water

Robert HookeRobert Hooke

•First to look at Cells under the microscope.

•He used microscope to look at everyday things (cork, leaves, fleas!)

What is a lens?What is a lens?

Curved piece of glass that bends Curved piece of glass that bends (refracts) light(refracts) light

Convex Concave

Types of MicroscopesTypes of Microscopes

SimpleSimple Uses 1 Uses 1

lenslens Uses lightUses light Example: Example:

MagnifyinMagnifying glassg glass

CompoundCompound Uses at Uses at

least 2 least 2 lenseslenses

Uses lightUses light Can Can

magnify magnify 1,000 times1,000 times

ElectronElectron Uses Uses

electrons electrons (tiny (tiny particles) particles) to magnify to magnify an object an object

Can Can magnify magnify 100,000 100,000 timestimes

Particles Particles bounce off bounce off the imagethe image

Nosepiece

Objective Lenses

Stage

Light

Base

Fine Focusing knob

Coarse focusing

Diaphragm

Arm

Body Tube

Eyepiece

Calculating MagnificationCalculating Magnification

How many times bigger are you How many times bigger are you making the object? making the object?

To calculate, Multiply the Eyepiece To calculate, Multiply the Eyepiece X the Objective LensX the Objective Lens

Ocularobjective

TM = TM =

Ocular Magnification X Objective MagnificationOcular Magnification X Objective Magnification

Calculating MagnificationCalculating Magnification

Ocular

objective

PrismPrism

Refracts white Refracts white light into all of its light into all of its colors.colors.

WHITE light is a WHITE light is a combination of combination of ALL colors of lightALL colors of light

Light can be TransmittedLight can be Transmitted

TransparentTransparent Objects are seen clearObjects are seen clear Transparency has NO colorTransparency has NO color

Light can be TransmittedLight can be Transmitted

TranslucentTranslucent Light transmitted through a Light transmitted through a

substance that scatters the lightsubstance that scatters the light The image looks fuzzy and lacks The image looks fuzzy and lacks

detaildetail

Examples: wax paper, etc.Examples: wax paper, etc.

Light can be transmittedLight can be transmitted

OpaqueOpaque A substance that does not transmit A substance that does not transmit

light.light. Doesn’t allow light to pass through Doesn’t allow light to pass through

itit Examples: your hand, a piece of Examples: your hand, a piece of

paper, etc. paper, etc.

Light can be absorbedLight can be absorbed

AbsorbedAbsorbed All of the light is collected in the All of the light is collected in the

object, no light appears out of the object, no light appears out of the object.object.

A pencil is yellow because yellow A pencil is yellow because yellow light bounces off it while all other light bounces off it while all other colors are absorbed.colors are absorbed.

Light can be reflectedLight can be reflected

Reflected - The bouncing back of Reflected - The bouncing back of lightlight

Light can be RefractedLight can be Refracted

Refracted – the bending of lightRefracted – the bending of light

What is a lens?What is a lens?

Curved piece of glass that bends Curved piece of glass that bends (refracts) light(refracts) light

Convex Concave

Who wears what lens?Who wears what lens?

Concave = Concave = Nearsighted (can Nearsighted (can not see far away)not see far away)

Convex = Convex = Farsighted Farsighted (cannot see near)(cannot see near)

Uses of light instrumentsUses of light instruments Natural light – Sun, Fire, LighteningNatural light – Sun, Fire, Lightening Optical instruments – Cameras, Optical instruments – Cameras,

Telescopes, MicroscopesTelescopes, Microscopes Lasers – Intense beam of light of one Lasers – Intense beam of light of one

color (medicine, industry, color (medicine, industry, communication)communication)

Fiber Optics – strands of glass that carry Fiber Optics – strands of glass that carry more information than copper wiresmore information than copper wires

The EyeThe Eye

Label the parts of Label the parts of the eyethe eye

The EyeThe Eye

1.1. CORNEACORNEA - transparent, outer layer - transparent, outer layer2.2. IRISIRIS - colored portion of eye - colored portion of eye3.3. PUPILPUPIL – “hole” in the iris that – “hole” in the iris that

opens/closes to allow more/less lightopens/closes to allow more/less light4.4. LENSLENS – gets wider/thinner to focus – gets wider/thinner to focus5.5. RETINA RETINA – membrane in back of eye – membrane in back of eye

contains rods &conescontains rods &cones6.6. OPTIC NERVEOPTIC NERVE –sends image from –sends image from

retina to the brainretina to the brain

The EyeThe Eye