Create a Coral Reef
Amy with her finished coral reef diorama and a close up of her model for coral polyp

Hi, I'm Amy O'Donnell, an educator at the American Museum of Natural History. I am fascinated by coral reefs and the creatures that live near them.

Did you know that giant coral reefs are built by thousands of tiny organisms called coral polyps (pah-lips)? The outside layer of a reef is alive. A coral polyp produces a cup-shaped skeleton around itself. The inside layers of a reef are made of the skeletons of dead coral, some of which lived millions of years ago.

Today, I'm going to show you how to make a model of a coral reef called a diorama, a 3-D scene set against a painted background. Dioramas come in many sizes. Like Museum scientists and artists, I love to make scientific models of different kinds of organisms from interesting materials in my classroom. I use these models to help people understand how these creatures live and their amazing body forms.

snipping off pink strings dangling from pink tube

Create a diorama of a coral reef.

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What's a Museum Diorama?

coral diorama

At the Museum, we create dioramas of many interesting environments. For the Milstein Hall of Ocean Life, we created a large diorama of a coral reef near Andros Island in the Bahamas. These dioramas give Museum visitors a chance to observe unusual ecosystems up-close. It takes Museum scientists and artists many months to construct a diorama. First, they go into the field to make careful observations of an ecosystem. Then they reconstruct all the organisms, plants, and rocks that they found into a life-like scene.

Cool Coral Facts

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  • The world's first coral reefs formed about 500 million years ago.
  • Coral reefs are made of millions of tiny, fragile animals called hard coral polyps, living and dead. A group of coral is called a colony.
  • Each different kind of coral, as a community, creates an amazing shaped structure. These architectural shapes are used by scientists to identify corals.
  • Coral polyps feed at night. They have tentacles with small stinging cells called nematocysts. Hard coral also get nutrients from the algae that live on them.
  • Coral reefs are found in shallow water because the algae that live with them need sunlight for photosynthesis. Photosynthesis is the process by which plants harness the Sun's energy and use it to turn water and carbon dioxide into their food, sugar. As corals compete for sunlight, the reef gets bigger and bigger.
  • Soft corals like sea fans and sea whips may be part of coral reefs, but they're not reef builders.
Image Credits:

Photos: Brain coral: courtesy of ReefNews, Jonathan Dowell; Fan coral: courtesy of Paul Janosi; Sea anemone: courtesy of California Academy of Sciences; Sponges: courtesy of REVEL Project, University of Washington; Andros Coral Reef: courtesy of AMNH, Denis Finnin; Supplies, What to Do (all photos); Amy's Extras (all photos): courtesy of AMNH; Illustrations: Sean Murtha