IBDP Physics - Mathematics and Measurements

Orders of Magnitude

Orders of Magnitude

Expressing numbers using powers of ten to represent a range of magnitudes in physics.

Uncertainties

Estimates of the difference between a measurement reading and the true value, caused by random or systemic errors.

Types of Uncertainties

Absolute uncertainty (fixed quantity), fractional uncertainty (fraction of total measurement), percentage uncertainty (percentage of total measurement).

Combining Uncertainties

Addition/subtraction (sum of absolute uncertainties), multiplication/division (sum of fractional uncertainties), power (magnitude of n times fractional uncertainty).

Scalars and Vectors

Scalars have magnitude, vectors have magnitude and direction. Distance is scalar, displacement is vector.

Vectors Representation

Vectors are represented by arrows, where the arrowhead shows direction and length indicates magnitude.

Combining Vectors

Combine vectors head to tail and use Pythagoras’ Theorem to find the resultant magnitude.

Error Bars

Represent uncertainty in measurements on graphs with vertical and horizontal bars at each point.

Lines of Best-Fit

Drawn to minimize distance between points and the line, with some points above and some below.

Uncertainty in Gradient

Calculated as ΔK = (kmax - kmin)/2, where k is the gradient and ΔK is the uncertainty in the gradient.