Citizen science is a collaborative way of creating knowledge in which everyday people take part in scientific research, contributing their observations, experiences, and ideas. Citizen science can take many forms, involving varying degrees of public participation and generating diverse outcomes. While sometimes it simply means helping collect data, in other cases it involves residents working closely with researchers to identify problems, shape questions, and interpret results. Some approaches aim to make science more democratic by giving the public a stronger voice in how knowledge is produced and used, while others focus on tackling issues such as public health, environmental justice, or community planning through partnerships that value local expertise. Across these different forms, citizen science serves not only as a method of inquiry but also as a way to empower communities, address inequalities, and influence decisions that affect people’s lives.

This module examines the concept of citizen science and how different modes of public engagement shape its practice and definition. The first lesson offers a brief overview of citizen science, accompanied by an introduction to the various ways in which citizens can participate in scientific research.

The second lesson features two video interviews that demonstrate how different modes of citizen engagement are applied in practice, highlighting two civic initiatives that use citizen science for environmental monitoring. The first case explores efforts to monitor water quality in Lake Pertusillo, in the Basilicata region of southern Italy – an area significantly affected by the long-term impacts of the fossil fuel industry. The second highlights a long-standing citizen science initiative in Tarragona, Spain, a city that hosts the largest petrochemical complex in Southern Europe.
Together, these examples demonstrate how different models of citizen engagement can shape scientific research, strengthen community involvement, and support environmental advocacy.