Yummy Sedimentary Sandwich

How clastic sedimentary rocks form

These science activities illustrate how clastic sedimentary rocks form when bits and pieces of older rock form layers of sediment on the seafloor or in lake beds. Bedding planes, which are slightly different in color, separate the individual layers of sediment. Major floods bring in thick layers of mud that contain rocks and boulders. Rainstorms create thinner layers of mud and silt. 

Just like sedimentary rocks the bottom layers are the oldest and the top layers are the youngest.

creating a tasty sedimentary sandwich

These science activities involve creating clastic sedimentary sandwiches using graham crackers, peanut butter  and jam are fun to create and eat. In this activity the graham crackers represent sedimentary layers of mud that have turned to stone. In between the layers are layers of chunky peanut butter or jam.

Sedimentary sandwich


  • Honey graham crackers
  • Chocolate graham crackers
  • Chunky peanut butter
  • Strawberry or raspberry jam
  • Knife
  • Paper plate


1.   Break two rectangular pieces of honey graham crackers in half to form four square pieces of light crackers.

2.   Break two rectangular pieces of chocolate graham crackers in half to form four square pieces of dark crackers.

3.   Lay one square of honey graham cracker on the plate.

4.   Spread a layer of chucky peanut butter on top.

5.   Place a square of chocolate graham cracker on top of the chunky peanut butter.

6.   Spread jam over the top of the chocolate graham cracker creating another layer for your sedimentary sandwich.

7.   Continue to add crackers, jam and peanut butter to your sedimentary sandwich until all the crackers are used.

8.   Count the number of layers that form your sedimentary sandwich.

9.   How many layers were created by a major flood? To find out the answer to this question count the number of layers of the chunky peanut butter.

10.  Count the number of times a volcano erupted and covered the sedimentary layers with lava by counting the layers of jam.

Our Volcano activity book contains 51 pages of fun activities about volcanoes.  Each of the activities have been "kid tested" by my grandchildren when they came over to my house.  Myrna Martin 

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More science activity ideas

  • Add animal crackers to your sedimentary sandwich to denote fossils.
  • Create a sedimentary sandwich using white and wheat bread.
  • Create cookies with several layers to show sedimentary rocks that have lithified.

Science behind the activity

Sedimentary rocks form in layers. During rainstorms and floods dirt, silt and sand are carried downstream to be deposited in deep ocean basins and lake beds. The layers are stacked one on top of the other with the deepest layers on the bottom just like your sedimentary sandwich.

KIDS FUN Science Bookstore

Check out Myrna Martin's award winning textbooks, e-books, videos and rock sets. The Kids Fun Science Bookstore covers a wide range of earth science topics.  Click here to browse. 

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