150 likes | 400 Views
IB Graphing. Error Bars. When measurement expressed with absolute uncertainty - graph with error bars. Bar is sketched as vertical and horizontal lines beginning at data point ending in horizontal line or cap. Bars are scaled to the graph axis. Error bars. distance (m) ±0.5.
E N D
Error Bars • When measurement expressed with absolute uncertainty - graph with error bars. • Bar is sketched as vertical and horizontal lines beginning at data point ending in horizontal line or cap. • Bars are scaled to the graph axis.
Error bars distance (m) ±0.5 time (s)±0.01* Error bars too small to show at this scale
Some error bars are different lengths why? Different instruments Calculated deviation from mean for each.
Usually give graphical data display because: • See relationship btw variables. • See outliers from data. • Show math relationship. • Finding constants.
How to graph • Graph axis independent (x) / dependent (y). Not always. • Scale – large. • Slope points – far apart. • Plot dot circled or dot w/bars. • Line or curve of best fit by hand. Can buy shape to help fit curves. Should touch error bars. • Best fit straight line may or may not pass through origin. • Transform curves. • Calculate slope & slope uncertainty for linear.
Graph Analysis • Linear y = mx + b test • Since slope is constant, y/x = k any 2 points
What graph is this? • Y = -kx. • This is a linear graph!
Inverse hyperbolic • Y = k/x yx = k • Transform graph by plotting y against 1/x to get linear.
Parabolic • Y = kx2. y/x2 = k • Or transform graph y against x2make it linear • What will the slope be?
Craters DBQStrobe Ball Drop • Kerr activity pendulum