CONFOUNDING (CONTROL/KEEP SAME) VARIABLES

TEMPERATURE
pH
Other C variables/precautions/standardisations
If not controlled in investigation, how to find how it could've influenced results
Keeping it constant
Monitor room temp thru out/ at beginning & end of experiment
Water bath: more temp variation in air than water/it keeps test tubes at constant temp
Monitor with thermometer
use data-logger to record temp
Adjust with hot/cold water
Temp of water bath as reliable as possible: measure temp of bath at beginning & end of reaction period (or more) to assess effect of any temp changes during reaction/to show there was no/little variation in temperature
EQUILIBRATION
Leave tube 1 in water bath for 5 mins before adding enzyme. To equilibrate /for solution to reach the temp of bath
Keep constant: use buffer
If 2 enzymes with diff optimum pH, then use 2 buffers
Volume/mass
Concentration
Standardise type/category
Time: between readings;duration; mixing
All controlled apart from 1-independent variable
No./rate of repeats
Read meniscus at eye level
Allows comparison of results/reproduce-able (diff techniques but same results)/repeatable (exact same technique) by someone else
Investigating 1 variable only
Same end point each time

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AS-level EMPA Notiz am EMPA: Common Themes - created from Mind Map, erstellt von Anna Rattu am 16/04/2014.