Tools of the Scientist

One of the most important tools is the compound microscope. Used to see the microscopic world or objects too small for the naked eye. Plant cells, animal cells and bacteria cells can be observed. Used to diagnose cancer

The compound light microscope The compound microscope has two sets of lenses, Each magnifies the what you are looking at

light to pass through a specimen on the stage to form an image. It can make objects 1000 times its normal size. light

The microscope must have two characteristics to be useful: 1. Magnification 2. Resolution

Magnification: the enlarging of the image so it can be seen easier

How to determine magnification: Multiply the eye piece by the objective. For example if the eye piece is 10X and the objective is 25X, your total magnification is 250X. 10 x 25 =250x 10x 25x

What is the total magnification of the following microscopes? Ocular: 10x Ocular: 15x objective: 40x objective: 100x

Poor resolution Good resolution 2. Resolution is the ability to distinguish between two points. Similar to digital cameras (mega pixels) or LED Televisions. Good resolution makes images clearer to view. Poor resolution Good resolution

Parts of the microscope. 1. Ocular lens/eye piece: Contains a magnifying lens, usually 10x or 15x.

Objective lens: has three different magnifying lenses: Scanning lens: magnifies image 10X Low power: magnifies 40X C. High power: magnifies 100x

3. light source 4. diaphragm: regulates amount of light that passes up towards the eye piece.

5. Base: support microscope 6. Arm: supports body tube

7. Stage: supports slide to be observed. 8. Stage clips: Holds slide down on stage

Nosepiece: hold objectives, can be rotated. 10. Course Adjustment: moves body tube in order to focus the image.

Fine Adjustment: moves body tube slightly to sharpen image. 12. Body tube: keeps proper distance between eye piece and objectives.

F Images viewed under the light microscope are upside down and backwards This is a compound light microscope view of the letter F placed on a slide in its normal position. F

Other types of microscopes 1. Transmission electron microscope: shines a beam of electrons through a thin specimen Works like a compound light microscope but higher magnification.

mitochondria

2. Scanning Electron Microscope: produces a 3D image. Runs a beam of electrons back and forth across the surface of the specimen. Magnification of 500,000x

Image under scanning electron microscope

Sperm on egg

Red Blood Cell

1. Red blood cells under a compound light microscope 2. Red blood cell in a capillary under a transmission electron microscope 3. Red blood cells under a scanning electron microscope

Other important lab techniques Chromatography Gel electrophoresis

A lab technique used to separate mixtures. Often done on paper Chromatography A lab technique used to separate mixtures. Often done on paper The chemicals separate based on density. The solvent is absorbed up the paper, separating the mixtures place on the paper by the scientist. Animation: http://www3.wooster.edu/chemistry/analytical/gc/default.html Solvent moves up paper

How paper chromatography works. Watch the water move up as it is absorbed by the paper. Separates the chemicals that make up the black dot as it moves.

2. Electrophoresis used to separate molecules such as DNA by size and charge charged molecules like DNA are placed in an electric field, they migrate toward either the positive or negative pole according to their charge .

Put DNA in the wells, Plug it in Separates based on size of molecules and charge DNA has a negative charge, so its attracted to the positive side. Smaller pieces move further Every ones DNA is unique Everyone's DNA separates in a unique pattern.

Gel electrophoresis is one way to determine your baby’s momma Also used to solve crimes Animation: http://fotofox17.deviantart.com/art/Gel-Electrophoresis-Animation-87035741

Electrophoresis pics The set up