Experimental Know-How Flashcards
Reliable results
give the same data each time the experiment by you and reproduced by other scientists
Valid results
Reliable
Fair test
Control variables
Temperature
Concentration of reactants
Volume of reactants
Mass of reactants
How to improve reliability
Repeat
Mean average
Potential hazards
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)
Accuracy
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
Precise
Close to the mean average
Use a sensitive instrument that can measure small increments
What are anomalous results caused by?
Human error (mistake when measuring, not using equipment correctly)
Is it too high or too low? What’s caused that?
When calculating average, ignore
What can cause a correlation?
- chance
- linked by a 3rd variable
- cause
How to calculate rate from a graph
Gradient
Δy/Δx
Gradient of a curve
Draw tangent
Evaluations
Valid? Fair test?
Enough results taken?
Reliable? Accurate? Precise?
Anomalous results?
