Clues of the Past
Kids will enjoy search for signs of earth-shaping events in this after-school activity. Once they discover that the ground under their feet has a complex story to tell, they'll want to tell the entire neighborhood what they've found!
The surface of the earth is constantly moving as water and weather erode the rocks and move the soil. Help kids find evidence of recent geological events -- and perhaps ancient events as well.
What You'll Need:
- A map of your community or a place of special interest
Using a map, encourage your child to explore his or her community or some other special place. Instruct them to mark what they find on their map. Floods, for example, leave watermarks on buildings. Also look for scouring of stream banks and for debris in tree branches.
Huge glaciers, which once scoured a large part of the North American continent, left distinctive marks behind. Large, exposed rock faces may have had long scratches cut into them as rocky undersides of glaciers passed over them.
If you live in the northern United States, direct your child to look for areas around the community that are flat and have many small lakes. These areas were scoured out by glaciers. Glaciers also "rafted" large rocks from one area of the country to another. Suggest looking for boulders of a kind of rock not normally found in the area.
Around the mountains, suggest to a child that he or she look for the same kind of scratches on rock faces that continental glaciers left behind and seek what geologists call U-shaped valleys. These are broad valleys cut by glaciers. Valleys cut by streams tend to be V-shaped.
Also suggest searching for areas where soil has been exposed and eroded by running water. Too much erosion causes stream banks to collapse
and can lead to landslides. If a child sees a very muddy stream, encourage him to follow it upstream to see if the mud comes from erosion along the banks. Kids can also look also for signs of erosion control in their community, such as trees planted on bare slopes.
On the next page, learn about a clothespin activity that really gets your child to shake a leg -- or a hand.