Grade Levels: K-3

This page provides information to support educators and families in teaching K-3 students about fossils. It is designed to complement the Fossils topic page on BrainPOP Jr.

Learning about fossils is a terrific way for children to explore Earth’s past. Most children have probably looked at fossils in natural history museums or have read about them in books. Nearly every child has learned about dinosaurs and prehistoric animals. Encourage children to view fossils as clues to Earth’s history, clues that help us understand how life has changed on our planet. Remind children that a fossil is a preserved clue left from a plant or animal that lived long ago. It is important for your children to understand that fossils do not have to be bones or parts of plants, but they can be a variety of remnants of life, such as nests, footprints, and droppings. Fossils can form in many ways and your children should understand that the process takes millions of years.

Many fossils are preserved remains of living things that are extinct. Remind your children that when a living thing is extinct, it is no longer living and none of its kind is left on Earth. Your class may want to screen the Extinct and Endangered Species movie, so children understand more about extinction. Some living things die out due to natural causes, such as dinosaurs, while others die out because of human interference, such as the dodo. People have found fossils of leaves, seeds, and cones of plants that lived millions of years ago, as well as fossil bones, shells, claws, teeth, and even whole skeletons. People have also discovered fossil footprints, eggs, nests, and droppings, which give insight into how living things moved or behaved.

Fossils can form in different ways, but some fossils form when a living thing dies and gets buried. Over time, the soft parts get eaten by bacteria or other organisms. The soft parts decompose, or break down, and the hard parts, such as shells, teeth, bones, or claws, are left behind. Over millions of years, layers of sediment pile on top of these remnants, creating pressure, which helps turn the lower layers into rock. Water can seep into the area and bring in minerals. Minerals slowly replace the hard parts and create a slow chemical change that turns the hard parts into a fossil of the same shape. Slowly, erosion causes the top layers to recede and wear away and the fossil can be found. Many fossils are found in riverbeds or on cliff sides, where water has eroded an area for thousands of years.

Sometimes a living thing dies and gets buried under sediment. It decomposes, but its outline remains in the sediment. Over millions of years the sediment turns to rock, but an imprint of the living thing is still left behind. Your children have probably seen fossil imprints of plants and shells and may have made imprints on their own using clay and different objects.

People have also found living things trapped in ice, such as woolly mammoths. The ice preserves the living thing and prevents it from fully decomposing. Woolly mammoths discovered in caves and river banks were found with tusks, fur, and even whiskers intact. Some species of trees release a resin, which is similar to tree sap. Insects and small animals can get trapped in the resin and over time it hardens into amber with the animal inside preserved. While these resin fossils and are not considered true fossils, they still provide valuable clues to Earth’s history and sometimes even contain small fragments of an organism’s DNA.

Scientists use fossils to learn about Earth’s history. We recommend watching the Earth movie together as a review. Remind your children that a paleontologist is a scientist who studies fossils and the remains of all life forms. You may want to explain that an archaeologist is slightly different; an archaeologist studies the remains of human life and culture. Explain to children that each fossil tells a story. For example, fossil footprints tell scientists about whether an animal walked on two or four legs, its length of stride, and its stalking behavior. A fossil bone can give clues about the size of an animal, its shape, and (due to carbon dating) when it lived. Scientists often compare living animals with fossil bones to draw conclusions. For example, today’s carnivorous animals often have sharp teeth for tearing meat, while herbivorous animals often have flat teeth for grinding and chewing. Scientists can draw comparisons with fossil teeth to today’s animals to infer what a living thing ate millions of years ago. Fossils of animals’ nests reveal a lot about their behavior and their habitat, and fossil droppings can also give clues about what an animal ate. Some fossil droppings show traces of plant materials or bones of other animals.

Encourage your children to learn about Earth’s history. Your children will probably have many questions about fossils, so encourage them to look up information on the Internet or in the library to learn more. This will help develop their research skills and support their natural curiosity about our world.