The concentration of tracer in a step experiment at the reactor inlet changes abruptly from 0 to . The concentration of tracer at the outlet is measured and normalized to the concentration  to obtain the non-dimensional curve  which goes from 0 to 1:
The step- and pulse-responses of a reactor are related by the following:
A step experiment is often easier to perform than a pulse experiment, but it tends to smooth over some of the details that a pulse response could show. It is easy to numerically integrate an experimental pulse response to obtain a very high-quality estimate of the step response, but the reverse is not the case because any noise in the concentration measurement will be amplified by numeric differentiation.