Earthquake Mitigation Measures Minimizing or avoiding the risks from earthquakes involves three subject areas. First is the ability to predict their occurrence. While scientists cannot routinely predict earthquakes, this area is of growing interest and may be a key factor in reducing risks in the future. This information is used to address the third area of earthquake risk reduction-mitigation measures. Following a discussion of prediction, assessment, and mitigation, the types and sources of earthquake information are presented. Earthquake Prediction A report on an erroneous prediction of an earthquake in Lima, Peru, states:
How Do Scientists Determine the Age of Dinosaur Bones?
How might the Fairlight area have looked million years ago? Introduction Fairlight is a small village located a short distance from the coast between Pett Level half a mile to the north-east and Hastings 4 miles to the south-west. Over the years coastal erosion has consumed much of the village outskirts and several homes have already toppled over the cliff. A recent study revealed the cliffs had retreated over metres in the last century alone.
Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. estimated age).
Age of the Universe How old is the world? Ancient commentators propose that the world may be simultaneously young and old. Gerald Schroeder One of the most obvious perceived contradictions between Torah and science is the age of the universe. Is it billions of years old, like scientific data, or is it thousands of years, like Biblical data? When we add up the generations of the Bible, we come to plus years.
Whereas, data from the Hubble telescope or from the land based telescopes in Hawaii, indicate the age at about 15 billion years. Let me clarify right at the start. The world may be only some years old. God could have put the fossils in the ground and juggled the light arriving from distant galaxies to make the world appear to be billions of years old. There is absolutely no way to disprove this claim. God being infinite could have made the world that way.
Geological Time Scale
Carbon , Radiometric Dating and Index Fossils Carbon dating is used to determine the age of biological artifacts up to 50, years old. This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils like those of the dinosaurs alleged to be millions of years old. This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers.
Geologic age dating is an entire discipline of its own. In a way, this field, called geochronology, is some of the purest detective work earth scientists do. There are two basic approaches: relative geologic age dating, and absolute geologic age dating.
Post warm-up question s on the board that focus on the content objective for the day. Students should speak and write in complete sentences during class in order to develop scientific academic language and clarify their reasoning. In small groups, give ample wait time for processing, provide sentence starters, give verbal and visual cues, accept verbal responses, and reduce written responses.
In this lesson, students connect fossil succession change in life over time to geologic time and relative age dating of fossiliferous rock units. Students begin the lesson by discussing geologic time and the use of rock units and fossils by naturalists in the past to establish a geologic time scale. Students then investigate the current geologic time scale, constructing a framework for subsequent investigations. Students next integrate into the framework of geologic time, the concept of fossil succession change in life over time through the investigation of the three basic principles of fossil succession and analysis of a fossil succession chart.
Students apply the concepts of geologic time and fossil succession to determine the relative ages of hypothetical rock units containing index fossils. Students then create their own hypothetical index fossils and hypothetical rock units, sequence the rock units by relative age, and explain how they determined this sequence. So, when we consider Earth time, we are thinking in huge time measurement units millions and billions of years long.
Naturalists before used relationships of rock layers oldest to youngest, bottom to top to create a relative time scale for the Earth. In the s, time measurement techniques based on the radioactive decay of atoms were developed. It was not until then that Earth scientists began to assign absolute ages to prehistoric geologic events.
Radiometric Dating and the Geological Time Scale
Possession of hard parts IV. Correlation of rock layers A. Matching rocks of similar age in different regions often relies upon fossils 1. William Smith late s—early s noted that sedimentary strata in widely separated areas could be identified and correlated by their distinctive fossil content 2. Principle of fossil succession — fossil organisms succeed one another in a definite and determinable order, and therefore any time period can be recognized by its fossil content V.
Dating with radioactivity A.
The geologic time scale (GTS) is a system of chronological dating that relates geological strata (stratigraphy) to time. It is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth’s history.
April Koch April teaches high school science and holds a master’s degree in education. Discover how geologists study the layers in sedimentary rock to establish relative age. Learn how inclusions and unconformities can tell us stories about the geologic past. We’ll even visit the Grand Canyon to solve the mystery of the Great Unconformity!
Your goal is to study the smooth, parallel layers of rock to learn how the land built up over geologic time. Now imagine that you come upon a formation like this: Example of a rock layer that is not smooth or parallel What do you think of it? How do you study it? How can you make any conclusions about rock layers that make such a crazy arrangement?
Geologists establish the age of rocks in two ways: Numerical dating determines the actual ages of rocks through the study of radioactive decay.
Until recent years, scientists who believe in creation haven’t had the necessary resources to explore radiometric dating in detail. A 10 gram sample of U Now that has changed, and some important discoveries are being made. When granite rock hardens, it freezes radioactive elements in place. The most common radioactive element in granite is Uranium This element is locked in tiny zircons within the granite.
As part of the decay process, helium is produced.
Radiometric dating (often called radioactive dating) is a way to find out how old something is. The method compares the amount of a naturally occurring radioactive isotope and its decay products, in samples.
This grade activity introduces students to age dating with exercises using relative and absolute dating. Geology and Geologic Time. Geological Society of America. Links to various activities and lesson plans concerning relative and absolute dating. Sequencing Time , University of California, Berkeley. This grade activity lets students place parts of their own life story into a time line so that they can better understand how geologic time is reconstructed by scientists.
Who’s on First , University of California, Berkeley. This grade activity introduces students to the idea of sequencing information in overlapping data sets and the Principle of Superposition, which is a core concept in relative dating. This website is a book chapter about geologic time. Offers history of age dating, stratigraphic principles, rock correlation, fossil correlations, radiometric dating, and the geologic time scale.
This belief in long ages for the earth and the existence of life is derived largely from radiometric dating. These long time periods are computed by measuring the ratio of daughter to parent substance in a rock and inferring an age based on this ratio. This age is computed under the assumption that the parent substance say, uranium gradually decays to the daughter substance say, lead , so the higher the ratio of lead to uranium, the older the rock must be.
Mar 03, · Overview of the mechanics of radioactive decay as associated with radiometric or absolute rock dating. Coverage of key definitions (half-life, parent atom, daughter atom, etc).
Page with 4 varve sections x17 Download each PDF page. For one class set, print 4 copies of the 10mm rulers and 1 page each of the 4 pages of varve sections. Cut the rulers and varve sections apart. Each varve section has a number You could put each varve section and an enlarged ruler into a plastic ziplock bag or envelope – for easy handout to each pair – and for easy storage.
Students can work in pairs, lay the enlarged 10mm ruler across the layers on their enlarged varve section so they can count the number of varves in say a 5mm segment, and record that number as x out of 5. Divide x by 5 to get the number of varves per mm, then multiply that number by to get the number of varves per meter.
Perhaps have one student count the varves, then the partner counts the varves to check. They could average their counts – or recount.
Geologic time scale
March, 31 Note: This program originally aired under the title “Last Extinction. Before the last Ice Age, great mammals ruled the plains of North America: You can’t see anything like it today. But then, suddenly, they disappeared, and nobody really knows why. It happened so fast.
Dec 04, · How do scientists determine the age of fossils that have been under the surface of the earth for thousands of years? Scientific American Editor .
It’s true, we can measure decay rates and extrapolate backwards to get an age of the rock. However, there are assumptions involved. The first assumption is that the decay rate hasn’t changed. This isn’t a good assumption since we’ve been able to drastically change the decay rate in the lab, making it over a hundred times faster. If this happened at all in the calculated billions of years, it would throw off the calculation by several million or billion years, depending on how long and how mucher faster it was.
A second assumption is that there was no daughter element present at the beginning. For instance, uranium decays into lead. If there were any lead present at the beginning of decay, which, there probably would be since lead is a useful element and so is “very good”, if someone were to measure the lead and uranium present at that time, it would already appear the Earth had been around for some time, even though it was just created.