Eating without Teeth

Gather several green leaves (look for ones that have fallen to the ground).  Place them in a resealable bag and seal. 

Hold the bag between you hands and rub the bag between your hands 25 times.  Observe the leaves.

Now add several small rocks the bag. 

Rub the bag together 25 more times.  Observe the leaves.

You'll find that the leaves without rocks did not change much at all.  However, the leaves in the bag with the rocks were crushed.

Rocks found near the rib bones of some dinosaur skeleton suggest that those dinosaurs swallowed rocks to aid in the digestion of food in dinosaurs who lacked grinding teeth.  Modern chickens swallow gravel to grind food inside their gizzard.

Fossils: Digging for Dinosaur Bones

Keep your eyes out for puzzles similar to these (I've found them at Michael's, for only a buck or two each):

They're wooden sheets of pieces that you punch out and then assemble.  The paper inside the package tells you how to assemble the pieces, but you don't need it for this activity. 

Punch out the pieces for one dinosaur and bury the pieces in a bucket of sand.  Have students dig out the pieces and then try to assemble the pieces.  Without the instructions in front of them, they'll be working as paleontologists do, trying to determine how the bones go together. 

Some other ideas to consider:
*Mix up pieces from two different dinosaurs in the same bucket of sand - students have to determine which bones go with which fossil, as well as assembling them.
*Don't put all of the pieces in the bucket - you don't always find a complete skeleton in one place.
*Consider putting the pieces in something that requires more excavation than just pulling the pieces out of sand. 

Even if your curriculum doesn't include a study of dinosaurs and/or fossils, you can use this activity as a lesson on the way scientists work.