Life in a body of water is very diverse: there are fish, snails, frogs, salamanders, turtles, insects and plants. On the microscopic level, diverse life forms are even more abundant. Algae, bacteria, and worms can be found, in addition to numerous kinds of protozoans, which were first viewed by Antonie von Leeuwenhoek in the late 17th century. Although they cannot be seen with the naked eye, these organisms are vital to the ecosystem. They provide food, produce oxygen and remove pollutants from the water.


  • Compound microscope
  • Water sample
  • Dropper or pipette
  • Microscope slides and cover slips


You will want to collect your water sample from still water; a pond or lake is ideal, but water from a slow-moving stream or creek will also work. Use a container with a wide base and do not fill it too full. This will ensure that the organisms have enough oxygen to survive until you can examine them. Place a few drops of water in the center of the slide and place a coverslip on top. Under low power, find an area on the slide that has a lot of activity.

Observe under high power, paying attention to how organisms move and interact. Aim to identify at least 5 different kinds of organisms, using the chart below, in addition to any other available resources.

Pond Life