Parasaurolophus was a dinosaur from the family Hadrosauridae. They lived during the Cretaceous period and made really funny sounds! 56 curiositymachine.org/challenges/72/ Make a Parasaurolophous Signal Horn . to make low frequency sounds that travel across a football fi eld! Here’s what you low frequency need to know: low pitch Frequency is how fast sound high frequency high pitch vibrates, and pitch is how we hear frequency. Low frequencies can travel longer distances than high frequencies. Loud sounds can also travel pretty far because they have a lot of force. Imagine how far a sound can travel when it’s loud and has low frequency! So, how can you build a parasaurolophous horn that makes sound that travels really far?? Parasaurolophus 57 Parasaurolophus was a large unique-looking herbivorous (that means plant-eating) dinosaur that lived during the Cretaceous period. This dinosaur had a long crest on top of its head that curved toward its back. Paleontologists think air could move through the crest and make low sounds like a trombone! 7.3_G_Senses_FINAL1 Parasaurolophus probably traveled in large herds around the same time as big meat eating dinosaurs like T. rex. If a T. rex was hungry, they had to watch out! Scientists think that Parasaurolophus could have made loud, low frequency signals to warn their friends that danger was Different crests, different sounds Air flowing through the long, curved crest nasal passage of Parasaurolophus (top left) helped near! Parasaurolophus was able produce the low-pitched sound these animals probably used to communicate. to make these sounds by directing Corythosaurus (below left) had a much shorter crest than Parasaurolophus. But its air through the long nasal passages crest probably also served to produce and ParasauroloPhus amplify sounds for communication. in its crest. 58 curiositymachine.org/challenges/72/ Modern tools help us model ancient ears. Using CAT scans, we create models of dinosaurs’ inner ears, like the duck-billed Corythosaurus dinosaur ear below. We compare them with the inner ears of living animals. Because we know what living animals can hear, we can infer what dinosaurs heard. Our studies tell us that dinosaur ears were best at hearing low-pitched sounds. Have you ever heard these instruments? Some instruments are better at making low pitch sounds than others. Write whether you think each instrument makes a high pitch or a low pitch sound! Hint : The ocarina longer saxophone travels through the air instrument, the lower pitch it will produce! tuba whistle recorder didgeridoo Parasaurolophus 59 Plan how to build your Parasaurolophus signal horn! List all the materials you plan to use. There’s a few here to get started. You should look for other things to use, and add them too! straws rubber bands balloon paper tube cardboard 60 curiositymachine.org/challenges/72/ Draw your plan for a Parasaurolophus signal horn design here. Label all the parts and how it will move so that everyone else can understand your amazing plan! Parasaurolophus 61 Start building! If you have trouble getting started, here’s one way to build a Parasaurolophus signal horn that can make sounds that travel really far: step 1: Find or make a tube that will be the body of your signal horn. step 2: Cut the round top off a balloon so that it is open at both ends. Cover one end of your tube with the cut end of the balloon. step 3: Insert a straw to the other end of the balloon. Make sure both balloon attachments are tight so no air escapes. 62 curiositymachine.org/challenges/72/ step 4: Test your design! Find a football fi eld or other big space and have a friend stand at different yards lines as you blow into the signal horn. How far does the sound travel? Parasaurolophus 63 How does it work? Sometimes it takes a few tries to make a machine work like you want it to! If yours doesn’t work the fi rst time, try to fi nd a way to make it better! Take notes on what problems you had, or what worked really well. 64 curiositymachine.org/challenges/72/ Draw or take a picture of your fi nished Parasaurolophus signal horn and put it here! Parasaurolophus 65 Put your thinking cap on! Reflect on what you’ve made! What can you change to make it work better? Did you learn how to do something new? Here’s one question to get you started: Different materials make very different sounds. Do you think that making the tube of your signal horn from other materials will help the sound travel farther? 66 curiositymachine.org/challenges/72/ There are animals living today that produce loud, low-frequency sounds – even underwater! Baleen whales make the loudest sounds of any animal living today at super-low frequencies. Cool, right? Parasaurolophus 67.