Problem
Hypothesis
Experiment design
Observations and data
Conclusion

For a history of why microwaved water became a topic of interest please see the detailed problem section of our plant experiment.

As stated in the introduction, our plant experiment lasted only 10 days because it was started so close to the end of the school year. Although I feel we provided solid evidence that microwaved water is harmless to plants over a short period of time, a long term experiment is needed if we want to say with any degree of confidence that microwaved water is completely harmless to plants. Instead of repeating the same experiment, I decided to use an aquarium ecosystem. This not only provides maximum exposure to the microwaved water, but allows us to observe any affects of microwaved water on a variety of organisms.

Plants, fish, and the microorganisms that help keep the water environment healthy create a complex interdependent ecosystem. If microwaved water is harmful to living organisms, it will surely have an affect on the interconnected relationships between all of the organisms within the small ecosystem, and we will be able to observe a difference between the control aquarium and our experiment aquarium.

We are keeping our experimental problem simple:

Does cooled microwaved water harm aquatic life?

Our main areas of observation will be general fish health, general plant health and growth, as well as the presence of helpful microorganisms. The latter will be determined through the monitoring of nitrate, nitrite, and ammonia levels in the water. We will also be monitoring the pH of each aquarium.

Before asking the students to form a hypothesis, a group of students researched how microwaves heat water and presented their findings to the class. By understanding the process of microwaving water, I felt the students could make a better judgement about the affects of microwaved water on living organisms.

Microwaved water will:

You can read some samples of student written hypotheses in our Student Weblog.

We will maintain 2 ten-gallon aquariums with identical populations of fish and plants. Water chemistry, as well as other factors in the 2 aquariums, will be monitored and logged carefully to keep both environments as close to matching as possible. Food will be measured and dispensed equally on a regular schedule. Observations will be posted on this website as the experiment progresses.

Each 10 gallon aquarium setup consists of:

Fish will be fed TetraMin PRO Tropical Crisps which will be supplemented with TetraMin supplements (e.g., bloodworms, minikrill, etc.). During long weekends and spring break, we will use TetraMin gel feeder blocks.

This will be a double blind study. No one connected with maintaining the aquariums, including myself, will know which tank contains the microwaved water. We will use filtered bottled water in both aquariums. The microwaved water will be boiled in a microwave oven for 20 minutes, then cooled and rebottled. One set of bottles will be labeled A and the other labeled B. A flip of a coin will determine which label will be assigned to the microwaved water. A third party, who is not invested in the results, will perform the microwaving and rebottling.

The aquariums will be labeled A and B, and only water from the bottles will be used to top off the tanks. When cleaning maintenance is required, fresh bottled water will be used, and when necessary more water will be microwaved. When needed, both aquariums will be cleaned the same day, and in the same manner.

Water chemistry, temperature, and other observations will be posted on this website (see "Observations and data" below).

A complete record of data and observations can be found here: