How science works Flashcards
What does proportional mean?
if two amounts increase and decrease at the same rate so there is always the same relationship between them.
How is proportion different from linearity?
A proportion concerns two ratios; A linear relationship concerns two variables.
How do you detect proportionality on a graph?
Step 1: Check whether the graph is a straight line. If the graph is not a straight line, it does not represent a proportional relationship.
Step 2: Check whether the line goes through the origin. If the graph does not go through the origin, it does not represent a proportional relationship.
How do you detect linearity on a graph?
A graph of two variables which are directly proportional to one another will always be a straight line through the origin.
What is a random error?
errors made by the person carrying out the measuring, and are usually down to timing incorrectly, or reading the instrument incorrectly.
How do you prevent random errors?
taking repeated measurements
what is a systematic error?
cause readings to differ from the true value by a consistent amount each time a measurement is made
What causes a systematic error?
observational error or environmental interference
How to prevent systematic errors?
use calibrated equipment, and eliminate any zero or parallax errors.
What is zero error?
Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero
What causes zero error?
faulty equipment that doesn’t return to zero correctly.
how to prevent zero errors
Check before you start measuring that the measuring instruments read zero for zero input.
What is a parallax error?
incorrect positioning of the eyes while taking a reading on a measuring scale.
How to prevent a parallax error?
align your eye at the same level as the pointer or scale.
