Experimental Know-How

give the same data each time the experiment by you and reproduced by other scientists

Reliable Fair test

Temperature Concentration of reactants Volume of reactants Mass of reactants

Repeat Mean average

Chemicals (gloves, safety goggles to reduce risk of the acid on skin or in eyes) Fire (heat proof mat to reduce risk of starting fire) Electricity Fumes (fume cupboard)

Human error Measuring the right thing, don’t include anything you shouldn’t Impurities Reaction unfinished -> not all the product produced Heat escaped into atmosphere Gas syringe -> empty at start Small increments

Close to the mean average Use a sensitive instrument that can measure small increments

Human error (mistake when measuring, not using equipment correctly) Is it too high or too low? What’s caused that? When calculating average, ignore

• chance • linked by a 3rd variable • cause

Gradient Δy/Δx

Draw tangent

Valid? Fair test? Enough results taken? Reliable? Accurate? Precise? Anomalous results?