Scientific method

Science aims to develop a good explanation of natural events (phenomena) that are observed.

Scientists develop explanations using the scientific method. This follows a specific way of working:

  • propose a hypothesis, an initial theory or explanation for an observation
  • make a prediction based on the hypothesis, suggesting how changing one factor will affect the outcome
  • Plan an experiment - this should test the prediction and the hypothesis on which it is based

Planning experiments

It is important to choose appropriate apparatus, materials and techniques.

Apparatus needed for titration: burette, pipette, conical flask and pipette filler.An example of equipment that could be used in an experiment

Apparatus

Containers including:

  • test tubes
  • boiling tubes
  • beakers
  • flasks

Measuring apparatus including:

Heating and electrical apparatus including:

  • Bunsen burners
  • electric heating mantle
  • water bath
  • power pack
  • leads, crocodile clips and electrodes

Chemicals

Reacting chemicals including:

Chemicals for analysis including:

Techniques

Standard techniques of measurement. The table gives some examples

ApparatusMeasures
ThermometerTemperature
pH meterpH
TimerTime
Digital balanceMass
Measuring cylinderVolume of liquid
BuretteVolume of liquid in titration
Gas syringeVolume of gas

Methods of analysis including

  • chromatography
  • flame tests to identify metal ions
  • chemical tests to identify gases or ions
  • titration

Methods for carrying out reactions including:

  • test tube reactions
  • heating methods, such as Bunsen burner, electric heating mantle, water bath
  • electrolysis