science endeavours

• science is the systematic knowledge that has been gained through observation, experimentation, and testing
• Ways to cultivate a questioning mind:

  • Be curious
  • Observe phenomena around you
  • Read widely
  • Ask questions
• Traits of a scientist:

  • Observant
  • Curious
  • Have a questioning mind
  • Perseverant
  • Hardworking
  • Risk-taking
  • Flexible in thinking
  • Adaptable
  • Tenacious
• Lab rules:

  • No running
  • Wear safety goggles
  • Tie up long hair
  • No eating, drinking, or food allowed
• Measuring tools:

  • Time: stopwatch; seconds (s)
  • Temperature: thermometer; kelvin (K)
  • Mass: electronic balance; kilogram (kg)
  • Length: ruler, measuring tape, metre rule, digital calipers; metre (m)
  • Volume: measuring cylinder; cubic metre (m3)
• Remember:

  • For a normal ruler, half a division (a division is 0.1) is 0.05, so your measurement must be given in 2 decimal places
  • For a measuring cylinder, half a division (a division is 1) is 0.5, so your measurement must be in 1 decimal place
• Bunsen burner:

  1. Luminous flame (yellow/orange):

  • Obtained when air hole is closed
  • Temperature is lower than non-luminous
  • Flame is flickering and unsteady
  • Flame is easily visible from afar

  2. Non-luminous flame (blue):

  • Obtained when air hole is opened
  • Temperature is higher than luminous
  • Flame is steady
  • Flame cannot be seen from afar

  3. How does a Bunsen burner work?

  • A Bunsen flame is produced when gas undergoes combustion
  • The collar of a Bunsen burner determines the amount of oxygen mixing with the gas
  • With a closed air-hole, very little oxygen enters, leading to incomplete combustion, forming carbon
  • The presence of glowing carbon particles in the flame turns it yellow and black carbon is often visible
  • With the air hole open, there is an increase in airflow to the burner, so there is more complete combustion, producing a hotter blue flame
• Accuracy and precision:

  • Accuracy: how close the result is to the actual correct value
  • Precision: how close the results are to one another
  • Errors:
  • Systematic errors: consistent (zero error on the weighing scale)
  • Random errors: unpredictable (human reaction time error)
  • To increase accuracy of the investigation:
  • Repeat the experiment as many times as possible for each variation of the independent variable and calculate the average
• Scientific investigations:

  • Independent variable: the changed variable
  • Dependent variable: the measured variable
  • Controlled variable: the constant variable
  • Try to state 3 controlled variables
  • Do NOT use the word "amount"
  • Research question should always start with "how"
  • Hypothesis is basically predicting the relationship between variables
  • Qualitative data describes results in color, odor, etc
  • Quantitative data presents results in numbers
• Tabulating data:

  • Must have a title: "The effect of (independent variable) on (dependent variable)"
  • The table (lines and all) should be in pencil
  • Words (headings, numbers) should be in pen