How old is the Earth? MS. PATEL DO NOW: Compare and contrast images of Earth. Draw a Venn Diagram is needed. The Formation of Earth Video HTTPS://WWW.YOUTUBE.COM/WATCH?V=QVWZYOFTUAQ Driving Question 1: WHY DOES EARTH LOOK SO DIFFERENT FROM THE WAY IT USED TO LOOK? Big Bang Theory! THE THEORY THAT EXPLAINS THE BEGINNING OF SPACE AND TIME. Let’s bring it back to science: The Big Bang Theory happened 13.8 billion years ago. This marked the fiery birth of the universe. Even though no one witnessed this event, physicists and astronomers are confident in this theory. How old do you think Earth is? Read the article at your desk How old have scientists calculated Earth to be? “By dating the rocks in Earth's ever-changing crust, as well as the rocks in Earth's neighbors, such as the moon and visiting meteorites, scientists have calculated that Earth is 4.54 billion years old, with an error range of 50 million years.” -4.54 billion years old What are some previous, failed attempts that scientists used to date the Earth? -Made several attempts in the past 400 years -Attempted to predict the age based on changing sealevels -Time it took for Earth or sun to cool present temperatures -Salinity (saltiness) of the ocean How do scientists use rock evidence to date the Earth? -Scientists used PLATE TECTONICS -Since plate tectonics constantly change and revamp the crust, the first rocks have been recycled, melted down, and reformed. What other types of evidence do scientists use to support the age of the Earth? -Radiometric Dating (scientific age of Earth) The Great Unconformity -One of Geology’s deepest mysteries -Gap of missing time in the geological record, between 100 million and 1 billion years long. -Geologists can learn a lot about Earth’s history by studying sedimentary rock layers. Unconformity -A break in time in a continuous rock record. -Caused by a period of erosion or a pause in sediment accumulation How do we know how old the Earth is? -The oldest rocks on Earth were found in northwestern Canada near a lake -They are dated to be 4.03 billion years old -Rocks that are older than 3.5 billion years old are found on all continents What is radioactive decay? Relative vs. Absolute Dating What is zircon and how is it significant in the study of Earth’s early history? Zircon: Tiny survivors of Earth’s early era -Very tough crystals -Can survive processes like erosion, transport, and metamorphism. -Key mineral/tool used by geologists to determine the age of rocks -Oldest Zircon dates back to 4.4 billion years ago Why is it hard to find ancient rocks? - Earth formed about 4.6 billion years ago from a disk of gas and dust circling the sun. -Most of the material has been recycled into Earth’s interior several times by the plate tectonics -Plate tectonics continue to shape our planet’s surface HOMEWORK DUE 9/13 -PLEASE COMPLETE THE PRE-LAB QUESTIONS IN YOUR M&M RADIOMETRIC DATING LAB HANDOUT -YOU CAN NOT PARTICIPATE IN THE LAB IF YOU DO NOT COMPLETE THE PRE-LAB. THIS RESULTS IN A ZERO!! -WE WILL BE COMPLETING A LAB NEXT WEEK. M&M Radioactive Dating Homework- DUE TOMORROW 9/10 Name and explain two types of evidence used to support the theory the Earth is 4.6 billion years old. (1 paragraph, please use one academic resource)
