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Build Your Own Simulated Matrix Sifter!

In this activity, students will be challenged to engineer their own simulated matrix sifter to practice their microfossil sifting skills!

Photo of microfossils being sorted in the Tar Pits micro lab

Make Your Own Simulated Matrix Sifter

In this activity, students are challenged to engineer their own simulated matrix sifter to practice their microfossil sifting skills! Microfossils are just what they sound like - very small fossils. When we excavate bones of megafauna (large animals), there is often still dirt stuck to those bones. That dirt and the dirt surrounding the megafauna bones are actually FILLED with these tiny fossils. When we examine the microfossils, we're actually getting a better look at the "locals" of Los Angeles during the Ice Age. Think insect legs, fish scales, mouse toes, etc. One of the most important parts of excavating fossils is sifting through the matrix to find those microfossils!


  • Measuring cup or ladle
  • 2 aluminum baking tins (9x13 or larger recommended)
  • Small toys or rocks that are larger in size than the matrix

Simulated matrix materials:

  • Gathered simulated matrix
    • Gather some dirt from your neighborhood. You will need at least 3 cups of dirt with varying-sized grains of dirt and small rocks.
  • Found simulated matrix
    • Rice
    • Quinoa
    • Barley
    • Mix of whatever grains you have in your pantry
  • Purchase simulated matrix
  • Sifter
    • Purchase a fine mesh sifter or colander
    • Make your own found-object sifter
      • Pipe cleaners
      • Wooden kebab skewers
      • Chopsticks
      • Cardboard tubes (toilet paper or paper towel tubes will work!)
      • Mesh produce bag
      • Burlap
      • Scissors
      • String or twine
      • Masking tape


  • Make your simulated matrix.
    Create your simulated matrix by putting your dirt, grains, or birdseed into one of the aluminum trays. Hide your small toys or rocks in the matrix. 
    Image of two kids mixing simulated matrix in an aluminum tray


  • Engineer your sifter. 
    Set up all your supplies for creating your sifter. Begin by making a frame to hold the mesh or screen. Attach your mesh or screen to the frame. Use the other aluminum tray underneath the sifter to catch the smaller grains of your "matrix". 
    mesh produce bag being stretched and shaped with pipe cleaners to create sifter
  • Sift your matrix!
    Test out your sifter by gently scooping some of your simulated matrix onto the mesh of your sifter. Gently move the matrix around on top of your screen or mesh, keeping an eye out for any microfossil toys you find!
    child's hand holding small toy they sifted from their simulated matrix