requestAnimationFrame API: now with sub-millisecond precision

Science Explorer. Frequently Asked Questions. Multimedia Gallery. Park Passes. Technical Announcements. Employees in the News. Emergency Management. Survey Manual. The beginning of the story starts at the bottom of the canyon and moves forward in time as you get closer to the rim.

Mid-Atlantic Ridge

Park attendance is managed via the Disney Park Pass reservation system —to enter a park, both a park reservation and valid admission for the same park on the same date are required for Guests ages 3 and up. Learn more. Upon reopening, theme parks, Disney Resort Hotels, restaurants and other offerings may be modified, limited in capacity and subject to availability or closure. Follow all posted instructions while visiting Walt Disney World Resort.

Geologists have used this method to date rocks as much as 4 billion years old Click on the “Show Movie” button below to view this animation.

Most sedimentary rocks are laid down in flat, horizontal layers. These can later tilt and fold due to tectonic activity, and river cuttings can cause gaps among the layers. Relative dating arranges geological events — and the rocks they leave behind — in a sequence. The method of reading the order is called stratigraphy layers of rock are called strata. In this activity, students observe rock layers located near Whanganui, watch an animation about how they were formed and use relative dating to work out the order in which rocks were created.

Scientists use diagrams and models to communicate information. Students need support and practice to become familiar with and know how to use these science communication tools. This activity is part of our collection on dating the past. The introductory article has links to related articles, activities and media. Read our latest newsletter online here. Nature of science Scientists use diagrams and models to communicate information. Related content This activity is part of our collection on dating the past.

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Radioactive Decay and Absolute Age Determinations

What was missing from the early geologic time scale? While the order of events was given, the dates at which the events happened were not. With the discovery of radioactivity in the late s, scientists were able to measure the absolute age , or the exact age of some rocks in years. Absolute dating allows scientists to assign numbers to the breaks in the geologic time scale.

Radiometric dating and other forms of absolute age dating allowed scientists to get an absolute age from a rock or fossil.

That is, with increasing age, the amount of rock of that age decreases. An animation to explain the three main types of unconformities – disconformities, This scheme has proven useful in dating rocks that have undergone metamorphism.

HTML5 canvas, which started as an experiment from Apple, is the most widely supported standard for 2D immediate mode graphics on the web. Many developers now rely on it for a wide variety of multimedia projects, visualizations, and games. However, as the applications we build increase in complexity, developers inadvertently hit the performance wall.

This article aims to consolidate some of this body into a more readily digestible resource for developers. This article includes fundamental optimizations that apply to all computer graphics environments as well as canvas-specific techniques that are subject to change as canvas implementations improve. In particular, as browser vendors implement canvas GPU acceleration, some of the outlined performance techniques discussed will likely become less impactful.

This will be noted where appropriate. Note that this article does not go into usage of HTML5 canvas. JSPerf is a web application that allows developers to write JavaScript performance tests. JSPerf runs each approach as many times as possible over a short time period and gives a statistically meaningful number of iterations per second. Higher scores are always better! Visitors to a JSPerf performance test page can run the test on their browser, and let JSPerf store the normalized test results on Browserscope browserscope.

Because the optimization techniques in this article are backed up by a JSPerf result, you can return to see up-to-date information about whether or not the technique still applies.

Dating rocks animation

If you’ve been using requestAnimationFrame you’ve enjoyed seeing your paints synchronized to the refresh rate of the screen, resulting in the most high-fidelity animations possible. Plus, you’re saving your users CPU fan noise and battery-power when they switch to another tab. There is about to be a change to part of the API , however. The Timestamp that is passed into your callback function is changing from a typical Date.

If you use this value, you will need to update your code , based on the explanation below.

Rock and Fossil Age Dating Exercise Radioactive Isotopes – the “Clocks in Rocks” animation Phases of the Moon ( download to play) · animation​.

Subscriber Account active since. Disney’s live-action ” Aladdin ” is now in theaters and while the main story is still in tact, the remake takes a lot of liberties from the original animated classic. Keep reading to see the biggest changes the live-action movie makes from Disney’s original animated classic. In the original movie, “Aladdin” opens on the song “Arabian Nights” with a peddler riding across the desert on a camel on his way to Agrabah.

The remake scraps this entirely. The original opening of “Aladdin” contained the lyric ” where they cut off your ear if they don’t like your face ,” a line which was changed when the film was released on video to the friendlier ” where it’s flat and immense and the heat is intense.

Cosmogenic nuclide dating

Nicolaus Steno introduced basic principles of stratigraphy , the study of layered rocks, in William Smith , working with the strata of English coal Former swamp-derived plant material that is part of the rock record. The figure of this geologic time scale shows the names of the units and subunits. Using this time scale, geologists can place all events of Earth history in order without ever knowing their numerical ages.

The specific events within Earth history are discussed in Chapter 8.

Journals · Geology · GSA Bulletin · Geosphere · Lithosphere · Environmental & Engineering Geoscience · GSA Today · Full Issue Archive · Features · Rock Stars.

Variety reports that Dave Bautista Guardians of the Galaxy , Blade Runner will join the cast for the second season. A half-hour comedy drama, it is set in the past but features writing to relate to a modern audience. The show is meant to help introduce toddlers to the simplest core concepts of coding as a means of helping people.

This is limited series of 10 animated shorts. That might not mean a lot to the kids of today, but anyone over 30 grew up with Charlie Brown and the Peanuts gang on TV and in the newspaper. The Book Club that was part of her daytime TV show could turn novels into bestsellers overnight. The film follows their journey as the watering hole that is home to her and her family dries up, and she risks taking her family in search of food and water, though they might not survive the journey.

Night Shyamalan. When you can watch: Servant debuted on November 28, Be sure to read our review of the first episodes. Read our review of the first season. It will focus not on the huge famous immigrants that have made worldwide impact, but the everyday lives and struggles that we all share.

7 Geologic Time

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The significance of the magnetic stripes was only revealed when their ages were discovered from dating magnetic reversals in volcanic rocks accessible on land.

Radioactive decay has become one of the most useful methods for determining the age of formation of rocks. However, in the very principal of radiometric dating there are several vital assumptions that have to be made in order for the age to be considered valid. These assumptions include: 1 the initial amount of the daughter isotope is known, 2 neither parent or daughter product has migrated into, or out of, the closed rock system, and 3 decay has occurred at a constant rate over time.

But what if one or some combination of these assumptions is incorrect? Then the computed age based on the accumulation of daughter products will be incorrect Stasson In order to use the valuable information provided by radiometric dating, a new method had to be created that would determine an accurate date and validate the assumptions of radiometric dating. For this purpose, isochron dating was developed, a process “that solves both of these problems accurate date, assumptions at once” Stasson A natural clock must meet four requirements.

FOSSILS: how fossils are dated