sidewalk fossil

Sidewalk Fossils                        

sidewalk fossil

by
Kenneth Fuller
(copyright information 2003)

Field Activities

Introduction to sidewalk fossils

The concrete of which sidewalks, and other structures, are made is actually a kind of stone.  To be exact, it is synthetic calcareous conglomerate  Synthetic means, " It is the real thing but put together by human, rather than by natural, processes".  Conglomerate means, "A stone made of sediments of different sizes mixed together, in this case, sand and gravel".  Calcareous means, "The cement holding this stone together is calcium carbonate".

These activities may be done by groups of students on a field trip, or individually on their own.

Leaf Fossils

Sometimes leaves or other objects fall into the concrete while it is still wet, like mud.  In the finishing process they may become buried, partly buried, or merely pressed into the surface.  As the concrete is lithified (turned to stone), hardened, the impressions of the objects become fossils.  Just like natural fossils.

1. Draw a picture of each different kind of leaf.  Include as many details as you can, veins, leaf margins, stem.  It may be necessary to combine details from several fossils of the same kind (just be sure they are the same kind).

2. Try to identify the kinds of plants the leaves came from.  How do you know? (Field guides to plants would be helpful.)

3. Search the area around the fossil location for plants (trees) with leaves of the same kinds as the fossils.

4. Any other notes of interest.

Animal Track Fossils

It is not rare for animals to walk through wet concrete while it is still wet and can take imprints, like wet mud.  When the concrete, or mud becomes lithified (hardened into rock) the foot prints become fossils.

1. Draw a picture of each kind of print you find with as much detail as you can.

2. Identify which prints are left, right, front, back.  How do you know?

3. Try to identify the animal which produced each kind of track. Cat? Dog? Crow? Opossum?  How do you know?
    (Field guides to animals, or animal tracks would be helpful.)

4. If the track is long enough, sketch the whole track.  Which direction was it going?  Was it walking? Running? Hopping?
     Or something else?  How do you know?

5. Any other notes of interest.

Human Track Fossils

It is not rare for people (either accidentally or deliberately) to walk through wet concrete while it is still wet and can take imprints, like wet mud.  When the concrete, or mud becomes lithified (hardened into rock) the foot prints become fossils.

1. Draw a picture of each kind of print you find, include as much of the pattern on the sole of a shoe as you can.

2. If it is a shoe print, what is the size of the shoe.  Where did you find a chart to convert shoe length to shoe size?

3. If the track is two steps or longer, sketch the whole track. Which direction was the person going?

4. Was the person walking? Running? Something else?  How do you know?

5. Any other notes of interest.

Bicycle Track Fossils

It is not rare for people (either accidentally or deliberately) to ride through wet concrete while it is still wet and can take imprints, like wet mud.  When the concrete, or mud becomes lithified (hardened into rock) the wheel prints become fossils.

1. Draw the patterns of the treads of each tire with as much detail as you can.

2. Sketch the entire track.

3. Identify the track of the front tire, and the track of the back tire. How do you know?

4. Which direction was the bike going? How do you know?

5. How fast was the bike going? How do you know?

6. Any other notes of interest.

(To verify your hypotheses [ How do you know's] see the Lab Activity.)

Wheel Track Fossils

It is not rare for people (either accidentally or deliberately) to ride through wet concrete while it is still wet and can take imprints, like wet mud.  When the concrete, or mud becomes lithified (hardened into rock) the wheel prints become fossils.

1. Sketch the entire track.

2. Draw a section of the track with as much detail of each wheel as you can find.

3. Which direction was it going? How do you know?

4. Identify the type of vehicle, skate, skate board, wagon, wheelchair, etc. How do you know?

5. Any other notes of interest.



Introduction

Lab activities

Student projects

Teacher's page


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