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Kids in the Creek - Fishless Acquariums




Pint jars make excellent aquariums for pond life if fish and other large animals are left out. Every pupil should have one of his or her own to watch and enjoy, even if the windowsills and bookshelves are filled for a time!

Such aquariums encourage pupils to make observations on their own and to share their discoveries with classmates. This is so much better than merely feeding goldfish in a classroom aquarium that has become just part of the furniture!

To make a fish-less aquarium, a pupil should place a centimeter or two of pond-bottom sediment in a jar, stick in a small water plant or two, and add pond water. Then put in a snail or two and a few water insects. The water will become clear after a while, allowing many tiny animals to be seen, perhaps for the first time! A magnifying glass will help.

Ideally, a class should set up jar aquariums at a nearby pond. Borrowing in a sense, small parts of the pond for a little while. Early fall is a good time to do this. Then the experience may be repeated in the spring to see what seasonal changes have occurred.

Well in advance of the trip to a pond, notes should be sent home to advise about clothing, especially rubbers or boots. Also, one or two parents may be invited along to participate as well as to provide additional supervision. Possibly a primary grade teacher and an upper-grade teacher can take their classes at the same time, having each older pupil be responsible for a younger one. It surprising how well they shoulder this responsibly!

If the whole class cannot be taken to the pond, perhaps you and a few pupils can bring the material to school. For a class of 30 pupils, you should fill four gallon jugs with pond water and get a small pail of sand or silt from the pond bottom. Also borrow some plants and animals from the pond - not too many!

Gather a few handfuls of small plants, and use a large kitchen strainer to collect some water insects, snails, and other small animals. Put them in a gallon jar of water.

If each sample is first dumped into water in a white pan, the creatures will be more easily seen. Then they can be spooned out. At school, they may be transferred to shallow pans for pupils to select the ones they want. To make the experience a really pleasant one, be sure that pupils:

  • Put only a few animals and plants in a jar, too few rather then to many. Crowding may cause them to die.
  • Keep the jars in a cool place, away from radiators. As a rule they should not be left in direct sunlight.
  • Move or shake the jars a little as possible. The creatures that live in them should be observed, not disturbed.
  • Add no food. The green plants make their own food, and the animals eat plants, or animals whose food came from plants.
  • Use pond water to replace any water that evaporates. Tap water containing chlorine is harmful to some creatures.

Over several days, pupils may investigate questions such as these:

  • How do they animals get around by legs, or by other means? Do any stay in one place, attached to objects?
  • What do the animals eat and how do they eat? How do they keep from being eaten?
  • Which animals carry bubbles of air with them, or get air through little tubes? Do any get air by moving gills through the water?
  • Do some animals avoid light? If you leave a paper bag over a jar and later remove it, can you see things you did not see before?
  • Where do the plants show signs of most growth in leaves, stems, or roots? Do they all have these parts?

Among the many other things that pupils may discover are these:

  • Hydra, named after a monster of mythology, snaring other small animals with their “arms”.
  • Tiny water “fleas”, such as Daphnia and Cyclops, darting through the water.
  • Small shrimp like animals with curved backs and many legs, called scuds, swimming along.
  • Diving beetles carrying their own air supply with them.
  • Caddis larvae pulling their cases along.
  • Mosquito eggs later changing into “wigglers” hanging from the water surface and later hatching as adults.
  • Ananchairs (once called Eldea) plants giving off tiny streams of bubbles in sunlight.

After a week or so, before interest wanes, have pupils return the plants and animals to the community from which they were borrowed. Take another trip to the pond - make it just as important as the first one, for the express purpose of putting the creatures back.

Doing this instead of flushing them down the drain or throwing them out helps to instill respect for living things. A basic environmental ethic!

Source: "Teaching Science with Everyday Things"



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