Nice Video! Once the ruler is vertical, a second set square can be used at the top of the object to avoid parallax. That is to help you ensure your eye, the top of the object and the part of the meter ruler that you are looking at are all in line.
John Byrne hi can u explain how I can write this down in my exam for the answer The question says how can u use a set square to avoid parallel error ? You may draw a diagram to explain ur anwer
@@amnanajmee4243, thanks for the message. (Apologies in the delay replying - security settings restricted me seeing comments and responding.) So firstly, the word is "parallax" Sorry, can't draw diagrams in comments. Once you have the metre rule vertical as described by Mr Matheson in the video, you can place one edge of the set square against the metre ruler. As the set square has a 90 degree angle to it, then if you look along the other edge, your eye will be horizontally opposite the point you are measuring to. Therefore, this edge will be against the point on the ruler making it easier to read the height value off the ruler. Does that help???
