A qualitative data essentially provides the outcome of an experiment in a descriptive manner. It cannot be measured but can only be observed. For example: color of a solution, texture of a metal etc.
In contrast, a quantitative data provides a numeric value to explain the outcome of an experiment. It can be measured using appropriate tools. The data can be analysed through graphs to model the behaviour of a certain experiment or to predict an outcome. For example: temperature, volume, weight are all quantitative data. In reaction kinetics for example, the change in concentration of reactants is monitored as a function of time. Both, concentration and time are quantitative data and can be plotted to deduce the order of a reaction.
