{"showCoverPage":false,"bookCover":{"coverDescription":"

<\/p>"},"chapters":[{"params":{"content":[{"content":{"params":{"text":"

Welcome to the Calculating the Radius of Earth's Core Tutorial<\/strong>. This resource is designed to be used in full-screen mode with the table of contents always displayed. To set this mode, click the Expand button in the top right of the header AND click the Navigation Menu button in the top left of the header. Then begin making your way through the tutorial by watching the video below.<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Untitled Text"},"subContentId":"cd2b2d11-88ed-44af-8d53-c363ff918fb5"},"useSeparator":"auto"},{"content":{"params":{"decorative":false,"contentName":"Image","file":{"path":"images\/file-62b8dfd867867.jpg","mime":"image\/jpeg","copyright":{"license":"U"},"width":665,"height":770},"alt":"Cross-section through Earth with radial scale","expandImage":"Expand Image","minimizeImage":"Minimize Image"},"library":"H5P.Image 1.1","metadata":{"contentType":"Image","license":"U","title":"Untitled Image"},"subContentId":"c8bb3e0a-c4c2-46fd-a571-9271770bdc2c"},"useSeparator":"auto"},{"content":{"params":{"text":"

Above figure is a cross-section through Earth.
\nThe outer ring is Earth's surface, and the dot is the center of the Earth.<\/em><\/p>\n\n

\n
Instructions<\/span><\/span><\/strong><\/p>\n\n
\n\t
Pick a point on the Earth surface (the outer ring of the circle) and make that the epicenter of the earthquake. Put an X there.<\/span><\/span><\/span><\/li>\n\t
Draw a dashed line between the X and the dot in the center marking Earth's deepest point in the inner core.<\/span><\/span><\/span><\/li>\n\t
With a protractor, measure a 103\u00b0 angle (arc) along the outer ring of the circle right and left of your X and place dots in both locations. Example: a 90\u00b0 arc would put you at point 1\/4 of the way around the circle from where you started; a 180\u00b0 arc would put you on the side directly opposite your X. To measure this angle, p<\/span><\/span><\/span>lace protractor\u2019s center spot on Earth\u2019s center. Line up protractor\u2019s bottom line along radial line you just drew. Measure 103\u00b0 in one direction, then flip the protractor and do the same again in the other direction.<\/span><\/span><\/span><\/li>\n\t
Draw a slightly curved line (seismic ray) from the earthquake epicenter through the Earth's mantle to the points 103\u00b0 away (bend it slightly, as shown in the images on the next page, to represent the refraction through some of Earth\u2019s layers\u2014don\u2019t worry if not precise, just be consistent).The surface locations between your X and your dot will receive S waves from an earthquake; the area beyond will not and is called the shadow zone.<\/strong><\/span><\/span><\/span><\/li>\n\t
Repeat this procedure for 3 other epicenters scattered around Earth's surface.<\/span><\/span><\/span><\/li>\n\t
Use a compass to draw a circle that lies just below the bottom arcs of each seismic ray you drew. This is Earth\u2019s core\/mantle boundary. Any S waves that try to travel beyond 103\u00b0 will hit that boundary and get absorbed..<\/span><\/span><\/span><\/li>\n\t
Measure the radius of the circle you just drew and compare it with the scale bar in the image. <\/span><\/span><\/span><\/li>\n\t
The correct answer for the radius of the Earth\u2019s core is 3370km. How close is your answer to the correct one? If differences, why do you think so?<\/span><\/span><\/span><\/li>\n<\/ol>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Untitled Text"},"subContentId":"006f5a25-a23a-4f6c-8fa6-82e8fa160639"},"useSeparator":"auto"},{"content":{"params":{"text":"
When done with the video above, continue through the remaining pages of this book to review content and images from the video, explore some content more deeply, and test your understanding through interactive ungraded quiz questions. The final page of the tutorial is a list of Additional Resources for students who want to dig even deeper into some of the video contents. When you've reached that page, you're done.<\/p>\n\n
To navigate to the remaining pages of this tutorial, use the arrow keys that appear in the header and footer. Or use the table of contents navigation menu, which you can toggle open or closed by using the button on the top left of the screen. <\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Untitled Text"},"subContentId":"21f1f66d-bc68-4f8e-b688-e450a0bf87ab"},"useSeparator":"auto"}]},"library":"H5P.Column 1.18","subContentId":"d7bf0253-f2f2-423c-a80e-6146a7588f15","metadata":{"contentType":"Column","license":"U","title":"Calculating the Radius of Earth's Core"}},{"params":{"content":[{"content":{"params":{"decorative":false,"contentName":"Image","alt":"Seismic wave paths through the Earth","file":{"path":"images\/file-62b9ef2a15d85.png","mime":"image\/png","copyright":{"license":"U"},"width":1024,"height":480},"expandImage":"Expand Image","minimizeImage":"Minimize Image"},"library":"H5P.Image 1.1","metadata":{"contentType":"Image","license":"U","title":"Untitled Image"},"subContentId":"67c50854-021f-4389-a21b-a496add21074"},"useSeparator":"auto"},{"content":{"params":{"text":"
Above image: Patterns of seismic wave propagation through Earth\u2019s mantle and core. S-waves do not travel through the liquid outer core, so they leave a shadow on Earth\u2019s far side. P-waves do travel through the core, but because the waves that enter the core are refracted, there are also P-wave shadow zones. Source: Steven Earle (2016) CC BY 4.0<\/em><\/p>\n\n
\n
Why are the S- and P-wave paths through the Earth curved?<\/strong> <\/p>\n\n
Body waves as they travel through the Earth speed and slow down as they move into materials more or less rigid. So if you pay attention to just ONE layer like the crust or the Lithosphere or even just the Asthenosphere -- NOT CROSSING BOUNDARIES -- just going deeper into that one layer, what happens? The pressure increases, so the material gets compacted more and actually gets a bit denser within just that single layer. As a result, it becomes more rigid, and the waves speed up in that layer. When waves speed up, the wave front bends. (See further explanation in this IRIS video: Why do waves bend when they travel through the mantle?<\/a>)<\/p>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Untitled Text"},"subContentId":"9300ca8f-87a2-4785-9c09-a3f05f3e0fdd"},"useSeparator":"auto"},{"content":{"params":{"visuals":{"fit":true,"controls":true},"playback":{"autoplay":false,"loop":false},"l10n":{"name":"Video","loading":"Video player loading...","noPlayers":"Found no video players that supports the given video format.","noSources":"Video is missing sources.","aborted":"Media playback has been aborted.","networkFailure":"Network failure.","cannotDecode":"Unable to decode media.","formatNotSupported":"Video format not supported.","mediaEncrypted":"Media encrypted.","unknownError":"Unknown error.","invalidYtId":"Invalid YouTube ID.","unknownYtId":"Unable to find video with the given YouTube ID.","restrictedYt":"The owner of this video does not allow it to be embedded."},"sources":[{"path":"https:\/\/www.youtube.com\/watch?v=w4hvy2VfCg4","mime":"video\/YouTube","copyright":{"license":"U"}}]},"library":"H5P.Video 1.6","metadata":{"contentType":"Video","license":"U","title":"Why do waves bend when they travel through the mantle?"},"subContentId":"9ec57ddd-a8c9-4ffd-92f8-ca3438e2f3b0"},"useSeparator":"auto"}]},"library":"H5P.Column 1.18","metadata":{"contentType":"Column","license":"U","title":"Shadow Zones and Curved Paths"},"subContentId":"6a4134c3-2560-4404-9f4a-8ab13aae4322"},{"params":{"content":[{"content":{"params":{"decorative":false,"contentName":"Image","file":{"path":"images\/file-62b8e09b2dd27.jpg","mime":"image\/jpeg","copyright":{"license":"U"},"width":675,"height":798},"alt":"Cross-section through Mars with scale","expandImage":"Expand Image","minimizeImage":"Minimize Image"},"library":"H5P.Image 1.1","metadata":{"contentType":"Image","license":"U","title":"Untitled Image"},"subContentId":"3fff1140-6175-4236-846c-a1344165d9e3"},"useSeparator":"auto"},{"content":{"params":{"text":"
Above figure is a cross-section through Mars.
\nThe outer ring is Mars' surface, and the dot is the center of the planet.<\/em><\/p>\n\n
\n
Instructions<\/strong><\/span><\/span><\/p>\n\n
\n\t
Use the same general procedure as you used for the Earth to find the radius of the core of Mars.<\/li>\n\t
Mars has a radius of 3400 km, and an S-wave shadow zone that begins 7000 km or 118\u00b0 away on the surface. <\/li>\n<\/ol>\n"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Untitled Text"},"subContentId":"91cde075-c17a-4e00-8048-f45a6b6e0046"},"useSeparator":"auto"}]},"library":"H5P.Column 1.18","subContentId":"bb9ffd45-05af-4502-ae41-d626acb16b17","metadata":{"contentType":"Column","license":"U","title":"Mars' Core Radius"}},{"params":{"content":[{"content":{"params":{"text":"
For a print out of the activity in this tutorial see:
Calculating the Radius of Earth's Core.<\/a><\/p>
To see the full solutions for this assignment, open:
Solution: Calculating Earth's Core Radius<\/a><\/p>"},"library":"H5P.AdvancedText 1.1","metadata":{"contentType":"Text","license":"U","title":"Untitled Text"},"subContentId":"d652ddd4-5852-4162-b07d-5cb6801b75cf"},"useSeparator":"auto"}]},"library":"H5P.Column 1.18","metadata":{"contentType":"Column","license":"U","title":"Additional Resources"},"subContentId":"95d0caa7-c5c5-4c88-903f-0e9e7bcafeed"}],"behaviour":{"defaultTableOfContents":true,"progressIndicators":true,"progressAuto":true,"displaySummary":false,"baseColor":"#1768c4","enableRetry":true},"read":"Read","displayTOC":"Display 'Table of contents'","hideTOC":"Hide 'Table of contents'","nextPage":"Next page","previousPage":"Previous page","chapterCompleted":"Page completed!","partCompleted":"@pages of @total completed","incompleteChapter":"Incomplete page","navigateToTop":"Navigate to the top","markAsFinished":"I have finished this page","fullscreen":"Fullscreen","exitFullscreen":"Exit fullscreen","bookProgressSubtext":"@count of @total pages","interactionsProgressSubtext":"@count of @total interactions","submitReport":"Submit Report","restartLabel":"Restart","summaryHeader":"Summary","allInteractions":"All interactions","unansweredInteractions":"Unanswered interactions","scoreText":"@score \/ @maxscore","leftOutOfTotalCompleted":"@left of @max interactions completed","noInteractions":"No interactions","score":"Score","summaryAndSubmit":"Summary & submit","noChapterInteractionBoldText":"You have not interacted with any pages.","noChapterInteractionText":"You have to interact with at least one page before you can see the summary.","yourAnswersAreSubmittedForReview":"Your answers are submitted for review!","bookProgress":"Book progress","interactionsProgress":"Interactions progress","totalScoreLabel":"Total score","a11y":{"progress":"Page @page of @total.","menu":"Toggle navigation menu"}}

Activity Preview

Instructor Overview

Shared By

Metadata

Title

Subject

License

License Attribution

H5P Type

Accessibility

Shared On

Last Updated

Shared in Library

H5P ID