chapt 1 : scientific endeavour Flashcards
what is a hypothesis
a scientific statement that proposes a possible explanation to some event/phenomenon
what is an independent variable
changed variable
what is a dependent variable
measured variable
what is a constant variable
a variable that is kept constant to ensure a fair experiment
what is a measuring cylinder used for
to measure volume of liquids
what is a electronic balance used for
to measure mass of solid
what are the instruments to hold liquids
beaker and conical flask
what are the steps to light up a bunsen burner
- close air hole
- turn on the gas tap
- ignite a burner with light
- open air hole
what are the characteristics of a luminous flame
close/open air hole
colour of flame
visibility
suitability for heating
hot/not hot
does/does not give out soot
closed air hole
orange flame
high visibility
not suitable for heating
not as hot
gives out soot
what are the characteristic of a non luminous flame
close/open air hole
colour of flame
visibility
suitability for heating
hot/not hot
does/does not give out soot
open air hole
blue flame
low visibility
suitable for heating
very hot
does not give out soot
what are the characteristics of a qualitative data
involve senses
descriptive
what are the characteristics of a quantitative data
involve senses and measurements
numerical
error when nothing is placed on weighing scale but does not show zero
zero error
error when marking on an instrument is viewed at a wrong angle
parallax error
symbol - causes severe damage when in contact with body parts
corrosive
symbol - lead to irritation, allergies
harmful/irritant
symbol - causes harm to environment
environmental toxicity
symbol - releases oxygen easily
oxidising substance
symbol - may explode when heated
gases under pressure
symbol - causes toxic or harmful effect to body when breathed in, swallowed or in contact with skin
acute toxicity
symbol - may cause fire or explosion
explosives
symbol - highly flammable
flammable
symbol - causes breathing difficulties
carcinogenicity
what are the parts of a bunsen burner
barrel, collar, base, air hole
