1 Measurement Basics Standard International Units Length metre

1 Measurement Basics

Standard International Units • • Length metre Mass kilogram Time second Temperature kelvin Amount mole Energy joule Pressure pascal m kg s k mol J pa

Prefixes • • deci centi milli micro nano Pico kilo d c m µ n p k 10 -1 10 -2 10 -3 10 -6 10 -9 10 -12 103

Significant Figures • Rule 1 You must have the same number of significant figures in your answer as the least accurate quantity in the question • Rule 2 Carry through your calculation 1 more significant figure than will be in your answer

Drawing Graphs • Whenever possible use a form that will allow a straight line to be plotted • Choose a scale that will allow the graph to cover as much of the paper as possible • Label the axes with dimensions and units • For a straight line graph draw the best straight line you can passing through, or close to, as many points as possible. • For a curve draw the smoothest curve you can • Be aware of when it is acceptable to draw the line point to point

Lab Reports • Practical Notebooks and Reports • • • Your practical notebook must have i) Your name and course, on the front cover ii) An index at the front, kept up to date iii) all pages numbered All results and observations must be recorded and written in ink

• All measurements and observations must be recorded in the notebook, at the time they are obtained. The use of scraps of paper for writing down results is expressly forbidden and such scraps will be confiscated or destroyed. • Incorrect entries must not be erased or altered. If a mistake is made the incorrect entry should be crossed out with one stoke and the correct entry written above or alongside the error.

Finally! • ALWAYS include units • ALWAYS look critically at your answer and ask yourself if it is reasonable • Errors in use of a calculator can lead to large errors in your answer • IS THE ANSWER REASONABLE? ? ?

1) a) How many significant figures are there in the following! 234. 9 b) 45 c) 0. 000344 d) 1284765. 000 a) 4 b) 2 c) 3 d) 10 2) Use your calculator to find the following. a) 1. 23 x 10 -4 x 345 b) 7. 900 x 10 -3 c) 0. 00001 x 0. 000056 a) 0. 0424 b) 7. 900 x 10 -3 c) 5. 6 x 10 -10