scientific detection

representative- analysts work with samples. samples of any item must be representative.

preservation of samples- important to prevent any changes or deteriation of samples.

Planning- factors to be considered: where,when, how to collect samples, how much to take, storage, transportation

Formulae- any calculations needed in standard operating procedures

area of rectangle (formula)-

area in M2 = length of longer side X lenfth of shorter side

Calibration graphs-

Measurement uncertainty- all measuremnts have uncertainty. e.g- a drug purity may be given 99.1 +- 0.2%. indicates value lyes between 98.9 and 99.3%.

Key words-

random errors

systematic error

written descriptions- notes. quick and easy, record details overtime

drawings- visual information. quick sketch to a detailed, accuarte, measured drawing.

photographs and videos- quick accurate way to record. 24-hour surveillance. image-enhancements

comparing images- fingerprints, pictures of faces

indentify features- features to identify sample

compound light microscope- used to see things that are too small to be seen by eye. 2 magnifying lens. 1 called objective lens, other called eyepiece lens.

magnifying power- magnification (microscope)= magnification(eyepiece) X magnification(objective)

resolving power- detailed microscope= high resolving power. best light microscopes is about X1500