Science ideas for young children: Lakes versus rivers

Teach young children about science by comparing lakes and rivers.

Boy bending down in edge of lake

Michigan is blessed with a great deal of natural water features. In Michigan, you are never more than six miles from a lake, stream or river. You are also never more than 85 miles from a Great Lake. This article is part of a series by Michigan State University Extension about conducting science activities with children in the natural world. This can be done within a family, in a daycare setting, as part of school activities, with a 4-H club or with any group working with young children.

What is the difference between a lake and a river? Most children can come up with the answer quickly. Rivers are always moving and lakes do not. To quote from the song “Just Around The Riverbend,” “What I love most about rivers is, you can't step in the same river twice, the water's always changing, always flowing.”

Once children understand the primary difference, explore the following questions on what that difference might mean for the lake or stream and the creatures that live in it.

  • What adaptation might a creature have to be able to live in a river compared to a lake? How might a river fish look different than a lake fish? How might insects living in the river be adapted to that movement of water?
  • Which do you think would usually be warmer, a lake or a river? Why do you think that? Could you test it? Is it easier for trees to shade a lake or a river? If water is running off a parking lot into a river, how might that change the temperature?
  • Almost all creatures need oxygen to live, and for aquatic creatures, it is dissolved in the water. How might oxygen levels be different in a lake compared to a river? Usually rivers have more oxygen because the water flowing over rocks increases the oxygen level.
  • How might pollution behave differently in a river than in a lake? In a river, the water is always moving, so the pollution entering the river at a certain point today will probably be further downstream tomorrow. In a lake, the pollution tends to stay in the lake.
  • What about food sources in lakes versus rivers? Lakes are more likely to have rooted plants in the water as well as floating phytoplankton to support the food chain. Narrow rivers are more likely to get their food from leaves falling into the river in the fall, and some wider rivers have rooted plants.

With any of these points, there are always exceptions. How might a lake made from a dammed river affect any of the above discussion? Or a big, wide, river that moves very slowly? How might inlets or outlets affect a lake? When a river enters a lake, how might that affect wildlife? Sometimes fish like to hang out at inlets because of the food it brings in or the cooler water.

Enjoy the wonderful waters of Michigan and engage youth in some meaningful science questions while doing it.


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