- a logical and orderly procedure of investigation
STEPS:
Making observations
- process of using our senses to describe things and phenomena
Formulating a hypothesis
- data gathered from a set of observations
- hypothesis is a possible and reasonable explanation for the question or problem
Testing a hypothesis
- experiment is a designed procedure used to test the validity of a hypothesis
SETS OF VARIABLES
- Independent Variable - factor tested in the environment
- Dependent Variable - factor measured to determine the outcome
- Controlled Variable - one that can influence the outcome of an experiment
GROUPS
- Control Group - all except the independent variable applied
- Experimental Group - all of the variable are applied
Observing and recording experimental data
- any result should be recorded
- may include notes, tabulations, and graphs
- everything should be recorded accurately
Drawing Conclusions
- must be entirely based on the results gathered from the experiment
Theory - a hypothesis that has been repeatedly and rigorouly tested
Law or Principle - when theory has been proven to be consistently true and has passed the test of time
IMPORTANT TOOLS IN BIOLOGY
Microscopes
- instrument that uses lenses to produce an enlarged and focused image of a specimen
2 Important Properties
Magnification- ratio between the image size and the object size
Resolution - refers to the smallest degree of separation
KINDS OF MICROSCOPE
Compound Light Microscope - focuses and bends light through a speimen to produce a magnified image
Stereomicroscope - also known as the dissecting microscope
- it has also lower magnification than that of the compound microscope. This is used for dissecting small specimens
Electron Microscope - uses a beam of electrons instead of light to create an image
- Transmission Electron Microscope (TEM) - uses a magnetic field beam to focus a beam of electrons through a thin section of the specimen. Can magnify the image of an object about 100 000 times
- Scanning Electron Microscope (SEM) - gives a surface view of a three-dimensional specimen. Can magnify the image of an object about 10 000 times
- Scanning Tunneling Microscope (STM) -allows viewing of atoms on the surface of a solid. It can magnify a specimen over 100 million times. It has a needle probe with a joint so sharp that only one atom is at its point,
OTHER SCIENTIFIC TOOLS
Ultracentrifuge - a machine used to separate suspended particles in a mixture
Chromatography - used in separating substances in a mixture
Electrophoresis - used to separate substances in a mixture according to how fast they move when subjected to an electric current
X-Ray Diffraction - very useful for the analysis of protein crystals using x-rays of a single wavelength.
Spectrophotometer - a device used to determine the amount of proteins or nucleic acid present in a solution
Computer - very useful in storing vast amounts of information. It is also used to organize data, make long and complex calculations, and make graphs
