We went on a nature walk with our students on the banks of Yeşilırmak River in Samsun. Our Students collected garbage from the banks of the river. They became aware of the results of water pollution. We took water samples with the help of technicians. The technicians measured some water values such as mineral and pH values with the necessary equipments. The students witnessed this experience. The NGO "TEMA" supported us in our activity. They informed the students about water pollution and the possible results. With this activity, our students learned how waste thrown into rivers affect the seas, ocean and marine life.