Warm or Cold Activity

Warm or Cold Activity Card No one has ever seen a live dinosaur but scientists know a lot about them. Some ate meat, some only plants. They laid eggs. Dinosaurs lived between 230 and 65 million years ago. They lived on dry land. Scientists have worked out all these dinosaur facts from looking at fossils. But one dinosaur fact is still puzzling Dina Digg. For many years scientists believed dinosaurs were coldblooded animals, like modern reptiles, rather than warmblooded like birds and mammals. Now they are not so sure. Cold-blooded reptiles like crocodiles and lizards need to lie in the sun to warm up. Warm-blooded animals do not have to do this. Time to become a dino detective ... Cold-blooded animals get warm by lying in the sun. The size of an animal’s body makes a difference to how quickly it cools down again. Many dinosaurs were very big. If dinosaurs were cold-blooded, would being big be a problem? Or would being big be helpful? Do big things cool down faster or slower than smaller ones? WARM OR COLD Your challenge Help Dina Digg to explore if size matters. Discuss You can’t get a real dinosaur but you can use large and small plastic bottles to make model dinosaurs. If you fill the bottles with warm water you can see how long they take to cool down. What will you measure in your test? How will you record your results?

Getting started You could start by looking at how quickly water cools in different size bottles: To do the tests you will need: • Different sized plastic bottles with lids • Measuring jugs • Warm water • Thermometer and stop watch or data logger You might want to use a table like this one: Volume of bottle Temperature at the start Temperature after ? minutes Temperature after ? minutes Temperature after ? minutes You may want to record your findings in a table like this: 1 Birds could have descended from dinosaurs. Evidence Evidence Evidence Birds are warmblooded. This could mean that dinosaurs were warm-blooded not cold-blooded. Dinosaurs were descended from reptiles. Reptiles are cold-blooded. Need to know more about Could there have been both warmblooded and coldblooded dinosaurs? 2 The climate was warmer. Plenty of sunlight would help coldblooded animals warm up. So dinosaurs could have been coldblooded. It wasn’t warm everywhere on Earth. 3 Dinosaurs were very big. Big things cool down. Not all dinosaurs were big. 4 Dinosaurs had scales. Animals with scales, such as lizards, are... This could mean that dinosaurs are... Some dinosaurs had feathers. Animals with feathers are... If an animal has a layer on the outside like feathers or fur, can it get warm by lying in the sun? Try to investigate this. 5 Anything else you can think of? Can you find other scientific evidence to help you decide if dinosaurs were cold-blooded or not?