Experimental Data
The Nature of data b Data is the outcome of observation and measurement b Data may be acquired ê In the field ê By experiment
What is an experiment? b Data acquired under controlled conditions b Experiments involve ê Identifying relevant (key) variables ê Deciding on which variables are to be manipulated (controlled) ê Deciding on methods of measurement ê Obtaining and using suitable equipment Processing the data obtained.
Reproducibility b Experimental data should be reproducible ê Observations made under the same conditions should lead to the same findings. b Natural variability (ie. error) to be taken into account ê Cannot always reproduce conditions exactly. ê Statistics used to determine acceptable variation
Types of data The nature of data varies; based on b the aims of the experiment b the nature of the phenomena investigated b Methods of data collection
Activity b How would you collect data from/for: ê Preparation of new chemical compound? ê Examination of bacterial culture? ê Investigation of link between body temperature & time of death? ê Investigation of links between diet & health?
Possible Solution b Chemical analysis of products b Count or identification of cells b Temperature vs time data b Survey (Questionnaire) of target population
Types of data
Fitness for purpose b The nature of the data depends on the hypothesis being tested. b The same phenomenon may be investigated from a variety of viewpoints.
Activity b What type of data would you require if you were investigating a chemical reaction for: ê Reaction sequence? ê Structure of product? ê Kinetics (rate) of the reaction?
Possible Solution b Analysis of compounds present at each stage b Information on position of atoms within the molecule b Quantity of materials present over time
Experimental Planning b Decide on the purpose of your experiment b Read the literature for previous work b Devise a suitable experimental procedure b Assemble your equipment b Make measurements b Analyse results & draw conclusions
And Finally... b Review your findings b Start again!!
The End For now