Science chpt 1

• our 5 senses - sight, hearing, touch, smell and taste
• qualitative data involves


  senses and is usually descriptive
• quantitative data invovles


  senses and measurements taken using instruments
• whats a hypothesis?

  proposed explanation - explaining a pheomenon/propose solutions to a problem
• order of hypothesis

  hypothesis -> experiment -> results (data) -> conclusion
• whats a independent variable

  its changed in an experiment
• zero error


  instrument give a non-zero reading when measured quantity should be 0
• parallax error


  instrument used incorrectly making it less accurate/precise
• when marking on instrument is viewed from the wrong angle

  it is a parallax error
• ruler (parallax error)

  line of sight is perpendicular to markings on the ruler
• measuring cylinder

  line of sight must be in line with bottom of meniscus
• spring balance (parallax error)

  line of sight is perpendicular to marking on the scale
• thermometer (parallax error)

  line of sight is lvl with top of meniscus
• accuracy


  readings - very close/ same as true value
• precision


  reading is close to each other
• whats a dependent variable

  it is an observed/measured variable
• Why should the air-hole be closed when one is lighting a Bunsen flame?

  to prevent a strike-back
• Which type of Bunsen flame should you use when you are temporarily not heating something?

  luminous flame as its more visible and safer
• What is this?

  corrosive

  
• Effects for corrosive

  Severe damage when in contact with body parts
• What is this?

  Flammable sign

  
• Effects for flammable sign

  May cause fire and might produce poisonous gas in a reaction
• What is this?

  Irritant sign

  
• Effect for irritant/harmful sign

  May lead to irritation of the skin, eyes and nose. It also causes harm to ozone layer
• What’s this?

  Environmental toxicity sign

  
• What’s this

  Gases under pressure sign

  
• Effect for gases under pressure

  heated- may explode. Gas leak in enclosed space- oxygen deficiency
• What’s this

  Oxidising substance sign

  
• Effect for Oxidising substance

  Released oxygen easily and can cause a fire/ explosion
• What’s this

  Acute toxicity sign

  
• Effect for acute toxicity

  If breathed in/swallowed- toxic effects. It is fatal
• Effect for acute toxicity

  Degree of exposure & toxicity may affect level of health implications
• What’s this

  Explosives sign

  
• Effect of explosives

  May cause fire/ explosion. Explodes when in contact with heat
• What’s this

  Carcinogenicity sign

  
• Effect of carcinogenicity

  Breathing difficulties, infertility, damage to organs, cancer
• SI unit for volume

  m3
• SI unit for mass

  Kg
• SI unit for time

  S
• SI unit for length

  M