We don't have the sensors to see or feel electromagnetic fields yet, they might have some impact on us (still an "under-research" topic...).
Ondes Visibles! is an Android + Arduino application that helps people experimenting with and raising their awareness of electromagnetic fields (EMFs). It features tutorials giving you the very basics of EMFs as well as interactive experiments for low (LF) and high (HF) frequencies using home-made sensors.
Get a full description of the project here: http://webofthings.github.io/Ondes-Visibles/