Most children know that dinosaurs hatched out of eggs. Ask your child to hold her hands in front of her, and have her guess how big she thinks different dinosaur eggs were. You can tell her that many of her guesses are right. Explain that different kinds of dinosaurs hatched out of different-sized eggs, much in the way modern birds hatch out of different-sized eggs—some tiny, some pretty big. Show illustration of different-sized bird eggs. Explain that the largest egg of any bird today is the ostrich egg — which is about the size of a volleyball. If possible, have your child hold a cantaloupe or volleyball to get a sense of how big this egg is.
Tell your child that a dinosaur species known as Maiasaura hatched out of eggs similar in size to ostrich eggs. Show a picture of a full-grown Maiasaura. Tell your child that an adult Maiasaura was about 30 feet long, 6 feet tall and weighed 3-4 tons (about the weight of an African elephant). Tell her she is going to create a model of a Maiasaura nest. Show a picture of a reconstruction of Maiasaura nest
Make the Maiasaura eggs. Tell your child that based on fossils, scientists know that Maiasaura laid their eggs in groups in nests they dug in the ground. Each group of eggs, called a “clutch,” was organized in a circle inside the nest. Have your child paint her round rocks. Explain that scientists don’t know what color the dinosaur eggs were — so your child can use their imaginations to paint her eggs. She may wish to add speckled patterns like many bird eggs today. Let the paint dry.
Dig the Nest. In a sandbox, or large dirt-covered area, have your child create a Maiasaura nest — a circular area about 5-6 feet across. Your child can build up the edges of the nest, similar to the reconstruction in the photo.
Fill the Nest. Have your child organize their eggs in a group in the middle of the large Maiasaura nest. Next, explain that Maiasaura were too big to sit on their eggs like a chicken. So how did they keep their eggs warm? Plants. Have your child put leaves, pine branches, and other plant material on top of the eggs.
Make a picture of the nest. If available, use a camera to photograph the completed nest. Share with other friends and family members. As an alternative, you can draw a picture of the nest with crayons or paint.
Take It Further
If you want to create a dinosaur egg that “hatches,” try this: Put a small toy plastic dinosaur inside a balloon, inflate it and tie it. Then use paper mache to cover the balloon. To make paper mache, mix 2 cups flour with 2 cups water, and 1 tablespoon of salt. Drag strips of newspaper through this mixture and stick them onto the outside of the balloon. Let dry for a couple days. Then paint the outside of the dried paper mache. Let dry. When you are ready to hatch the egg, crack open the shell, and pop the balloon.