Practical questions - general tips Flashcards
what are control variables
things that would affect the dependent variable if they aren’t kept the same
why are control experiments set up to compare with the actual experiment
to prove that its definitely the independent variable that’s causing the effect
what should you do if you’re planning a method
- identify the variables
- identify hazards and precautions
- describe the stages of an investigation
- repeats!!
what should you do if you have to add to a results table
keep the numbers to the same number of decimal places
make sure you do what when presented with a results table
check if the column heading has/needs a unit
what does repeatable mean
if YOU do the experiment again and get the same results
what does reproducible mean
if SOMEONE ELSE carries out the experiment and get the same results
what are random errors
unpredictable differences caused by things like human error in measurements
how can random errors be reduced
by repeating the experiment and calculation a mean
what are systematic errors
cause measurements to be wrong by the same amount each time. for example, if you used a ruler to measure something but started from the end instead of at 0
what is accuracy
how close a measurement is to the true value
what is precision
how close measurements are to each other
how do you plot a graph
- decide on a suitable scale
- label x axis with independent variable and the unit
- label y axis with dependent variable and unit
- plot accurately with neat little crosses in pencil
- decide what kind of line to draw: straight, curved or point-to-point
