Dinosaurs became extinct millions of years ago. No one is certain why this happened. Here are a few theories: (A theory is a scientific explanation using evidence.)
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Have you ever have a bad dream? Imagine that you are looking out your bedroom window, and you see a giant dinosaur with its huge mouth full of sharp teeth staring back at you. Luckily, things like that only happen in dreams or movies!
When dinosaurs lived, the area was very different. The climate was very warm and tropical. There were many plants for the plant-eaters and plenty of animals for the meat-eaters.
Dinosaurs became extinct millions of years ago. No one is certain why this happened. So, scientists came up with some theories. A theory is a scientific explanation using evidence. Here are a few theories:
    1. Something happened that changed the climate. Maybe a huge comet or a meteor struck the earth and created large clouds of dust that blocked out the sun. The amount of rainfall changed, causing a drought that affected all of the plants and animals.
    2. Scientists knew that animals could be affected by diseases. Maybe a disease was spread rapidly among the dinosaurs that caused them to become sick or die.
    3. A sudden change in temperature could harm animals such as reptiles. Putting a turtle outside in the snow would cause it to die, if it were left there for very long. It is possible that the weather became very cold during the time of the dinosaurs and caused them to die out.

Write it!

Choose one of the theories of how dinosaurs became extinct. Write a story telling how it happened. Be sure to include illustrations. Share your story with friends and family.


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Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 4th grade science core.

Updated October 24, 2008 by: Glen Westbroek

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