Kitchen
Geology
GRADE
LEVEL: 4-6
TIME
REQUIRED: Two to three class periods
SETTING:
Classroom
GOAL:
To create a layered edible dish that demonstrates: (1) the layering of
rock strata, and (2) the movement of rocks that expose fossils.
OUTCOMES:
At the end of the lesson the student will:
- state the defining
characteristic of sedimentary rock,
- define index fossil,
- define uplifting,
overthrust, and faulting,
- and state how fossils
are exposed.
KERA GOALS:
Meets KERA goals 1.3, 1.4, 2.1, 2.2, 2.4, 2.6, 5.3, 5.4, 6.1, 6.2, 6.3
BACKGROUND INFORMATION
Sedimentary rocks are layered rocks. Chemicals in rivers, lakes, and oceans
precipitate particles from water. This precipitate then mixes with organic
remains (such as shells and skeletons) of organisms. Wind, rain, and ice
wear down surface rocks into bits of sand, soil, mud, pebbles, clay, and
loose sediments. All these various sediments eventually pile up layer
upon layer. Over time, pressure exerted by the weight of the top layers
compacts and cements the lower sediments to form solid rock. Younger rock
is placed on older rock. Each layer captures life forms of that period
in time. These preserved species are called index fossils. By observing
these index fossils the geologist can determine the age of the rock.
Sandstone is a sedimentary
rock made of layers of compressed and cemented sand grains. Shale is a
sedimentary rock made of layers of silt and mud. Limestone is a sedimentary
rock made of layers of carbonated sediments (sea life) that thrived in
a warm shallow sea. Fossils can be found in any sedimentary rock, but
in the Mammoth Cave area they are most typically seen in the layers of
limestone.
Rock strata can stretch,
bend, and break when they are subjected to heat and pressure. They are
constantly worn away on the surface by wind, rain, and ice. As the rocks
change, fossils become exposed.
MATERIALS NEEDED
- Clear glass container
12” X 18”
- Three boxes of
Jell-O of contrasting colors (red, orange, green)
- 1½ cup Coolwhip
or cottage cheese (blended)
- ¼ - ½ cup each
of carrots, nuts, pieces of apples (Avoid candies with food coloring
such as M & M’s)
PROCEDURE
ACTIVITY ONE:
SEDIMENTARY ROCK
Create a series of rock strata with fossils.
- Following the
directions on the box, mix a box of one color Jell-O and allow to partially
set-up (follow directions for soft-set or thickened Jell-O as shown
on box).
- When partially
setup, stir in Coolwhip or blended cottage cheese to make the Jell-O
opaque. Add ¼ cup sliced carrots to represent fossils. Allow to set
until firm.
- Mix a box of the
second color Jell-O and when partially set, stir in Coolwhip or blended
cottage cheese. Add ¼ cup nuts to represent fossils. Pour this mixture
on top of the first layer of Jell-O. Allow to set until firm.
- Mix the third box
of Jell-O and when partially set, stir in Coolwhip or blended cottage
cheese. Add pieces of apples to represent fossils. Pour this mixture
on top of the first two layers of Jell-O. Allow to set until firm.
PROCEDURE ACTIVITY
TWO:
EXTRUSION OF FOSSILS
Create
movement of Jell-O that is characteristic of earth’s movement to expose
the fossils. Cut 4”x4” squares of Jell-O. Use one square for each of the
following demonstrations:
- Uplifting.
Place a four- by four-inch square of Jell-O on a plate. Slide a knife
under the piece of Jell-O and gently lift. First the strata will bend
and then it will break. Once the pieces are standing on end, some of
the fossils may be exposed.
- Overthrust.
Cut another four- by four-inch square of Jell-O. Gently and evenly push
in from opposite sides of the square so the center rises up and one
half flops over the other half. Geologists call this overthrust. Notice
the older stratum is no longer under the younger strata.
- Faulting.
The surface of the earth is covered with cracks called faults. Sometimes
the land on one side can be uplifted and raised above the land on the
other side. Cut another 4” square of gelatin. Slice the gelatin into
two parts. Use a spatula to raise one side. This will show the way rocks
can move in relation to each other.
- Erosion. Wind
and rain constantly wears away sedimentary rocks, thus exposing fossils.
This may be demonstrated in various ways. Allow hot water to run over
a square of gelatin until fossils are exposed. Use a hair dryer to dissolve
and expose the fossils in a second square.
NOTE: Examine
how fossils are exposed with each type of earth movement. Hopefully, molds,
imprints, as well as fossil pieces will be exposed.
This activity adapted
from The Big Beast Book by Jury Both.
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