biology: chapter 2: scientific method

dissection(stereo)

-light is illuminated -image appears 3D -larger specimen and not individual cells -magnifies about 20x(low)

compound light

-light is illuminated -2D images -can view individual cells -high magnification -the best magnification is 1500x

SEM, scanning electron microscope

-electron illumination -3D image -high resolution and magnification -coated in gold and the electrons bounce off to give an exterior view

TEM, transmission electron

-electron illuminated -2D image -can see inside -high resolution and magnification -thin slices of specimen are obtained -electron beams bounce off

depth of field

the number of layers you see

eye relief

distance the eye should be from the ocular lens

resolution

clarity and detail seen

field of view

the circle of light you see

total magnification

objective lens x ocular lens

magnification

increase in size, ratio of seen to real size

anton van leeuwenhoek

father of microscopes, ground lenses, looked at everything especially out of his body, invented one of the early decent microscopes, was an apprentice where magnifying glasses were used to count cloth, taught himself grinding and polishing methods, got a magnification up to 270 diameters

a way to solve a problem, steps u take to identify a question, that comes from observations and inferring, you develop a hypothesis, experiment, then document this

what is the scientific method

observation

using your senses to take note of surroundings

inference

logically, when you make an assumption or prediction about something u observe

logical interpretation

about something you already know

take time to think logically and break down things into many steps that make sense

when investigating a question what do scientists have to do?

hypothesis

a statement that can be tested and presents a possible solution to a question

multiply the ocular by the objective lens

how do you calculate the total magnification of a compound microscope

decreases

as the field of view increases, magnification _____________

control group

a part of the experiment that does not have the variable, is not being tested and is used for comparison

experimental group

a part of the experiment that has the independent variable and is being tested

independent variable

what is being manipulated, changed or tested for

dependent variable

what is being measured

constants

the variables that remain the same between the two groups

-carry by the arm and the base -clean only with lens paper

what are some maintenance rules of a microscope

ocular lens

the body tube always contains the ________________

revolving nose piece

the objective lenses are always on the _________________

diaphragm

__________________ regulates light

qualitative observation

using your senses is described

quantitative observation

using a number

a cause and effect

what do u predict when making a hypothesis

µ

micron symbol? (micrometers)

observing what happens and is writing it down

what is the key to experiments?

gathering information and data

what may change the hypothesis?

yes, to see if they get the same results

should you repeat your experiment more than once? why?

verification

checking things out to make sure everything was valid and will happen again

help scientists learn from each other and use these experiences to help them with what they're studying or doing

what does sharing experiments do?