Validity confusion (1 Viewer)

[darkphoenix]

I am really confused about validity, for example use pendulum to measure gravity. I know that reliability is how consistent the results are, and accuracy relates to the equipments used and how close it is to the theoretical result, but how do I assess validity? Please explain

 

[LifeBoats]

Validity is essentially how well the experiment and the results address your aim. Did the pendulum experiment produce results that determined 'g'?
In order to address validity, you need to take into consideration the variables and whether they were kept constant (of course apart from the independent variable i.e. length of string or the angle from which the pendulum was released)