In this work, the authors propose an experiment aimed for undergraduate laboratories with the aim of introducing different novelties as a topic for practical sessions or student projects. The topics here investigated are appropriate for students with intermediate physics knowledge. Corona discharges are little studied in regular physics courses despite their practical importance in different areas, such as the distribution and transmission of electrical power, generation of ozone, particulate removal in air conditioning systems, improvement of wettability in polymeric materials, or the removal of electrostatic charges from the surface of airplanes among others. This work analyses the minimum voltage level leading to corona discharges and the influence of geometry and atmospheric pressure because these two factors are the most influential to determine the minimum voltage at which corona discharges appear.