hey wassup every1.my first post lol.neway, ive got a question which i cnt seem to find the answer to anywhere else so im hopin one of u lot could help me out. anyway heres the question. How do i find out the percentage error of a hard wood ruler compared to the actual graduations of the ruler which are 1mm. basically i am measurin the length tht an air column rises using a hard wood ruler dipped in cold water then gradually risen to 100degree c.so the range is 0-100degrees. so how do i obtain the thermal expansitivity of the co-efficient of the hard wood and then use tht to work out the %error created by the ruler.my starting length of the air column is 54mm.if u dnt understand the question cuz i ent worded it properly then its all gud, but cud sum1 tell me the thermal expanisitivity co-efficient of hard wood.thanx all.word up.