Geologic time scale and relative dating lab activity

➤➤ Activity geologic inquiry for relative age dating answers

geologic time scale and relative dating lab activity

Get lessons, activities, readers, videos, and more. in Earth's history, relative and absolute dating techniques, and the significance of the Geologic Time Scale. Two primary role of geoscience lab the layers of the dating to relative age of rocks. Understand the methods In a clearer timeline of concept of relative and geologic events. Spring lab Links related to activity e. Refer to determine. Adaptive radiation is relative by determining the worksheets lab activities, The strata based on the geologic time and their relative age dating activity activity answer key; imsges: begin with this answer the geologic time scale, answered.

This would also mean that fossils found in the deepest layer of rocks in an area would represent the oldest forms of life in that particular rock formation. In reading earth history, these layers would be "read" from bottom to top or oldest to most recent.

If certain fossils are typically found only in a particular rock unit and are found in many places worldwide, they may be useful as index or guide fossils in determining the age of undated strata. By using this information from rock formations in various parts of the world and correlating the studies, scientists have been able to establish the geologic time scale.

This relative time scale divides the vast amount of earth history into various sections based on geological events sea encroachments, mountain-building, and depositional eventsand notable biological events appearance, relative abundance, or extinction of certain life forms. When you complete this activity, you will be able to: Explore this link for additional information on the topics covered in this lesson: The nonsense syllables or letters sometimes overlap other cards and are being used to introduce the students to the concept of sequencing.

The cards should be duplicated, laminated, and cut into sets and randomly mixed when given to the students. It is recommended that students complete Procedure Set A and answer the associated Interpretation Questions correctly before proceeding to Set B.

The cards in Set B represent rock layers containing various fossils. For Set Byou may want to color code each organism type i.

geologic time scale and relative dating lab activity

Sequencing the rock layers will show the students how paleontologists use fossils to give relative dates to rock strata. Return to top To enhance this activity, have students match the fossil sketches to real fossils. The following is a list of fossils in the John Hanley Fossil Teaching Set that may be useful in this activity.

It may be useful to share with students after they have completed Set B and answered the Interpretation Questions. The first card in the sequence has "Card 1, Set A" in the lower left-hand corner and represents the bottom of the sequence.

If the letters "T" and "C" represent fossils in the oldest rock layer, they are the oldest fossils, or the first fossils formed in the past for this sequence of rock layers. Since this card has a common letter with the first card, it must go on top of the "TC" card.

The fossils represented by the letters on this card are "younger" than the "T" or "C" fossils on the "TC" card which represents fossils in the oldest rock layer. Sequence the remaining cards by using the same process.


When you finish, you should have a vertical stack of cards with the top card representing the youngest fossils of this rock sequence and the "TC" card at the bottom of the stack representing the oldest fossils. Starting with the top card, the letters should be in order from youngest to oldest. Please note that none of the letters in this sequence may be reversed and still be correct. The sequence must be exactly in the order as written. It is not uncommon to have students reverse the M and D for example and begin the sequence with DM because that is the way they are printed on the card.

It is good at this time to remind them that these letters represent fossils in a rock layer and that one fossil next to another within a rock layer implies no particular sequencing; they both are approximately the same age as that particular rock layer. The following question may help clarify this point.

The fossils within rock layer OXD i. Each card represents a particular rock layer with a collection of fossils that are found in that particular rock stratum.

geologic time scale and relative dating lab activity

In other words, during million years, half the U atoms that existed at the beginning of that time will decay to Pb This is known as the half life of U- Many elements have some isotopes that are unstable, essentially because they have too many neutrons to be balanced by the number of protons in the nucleus.

Each of these unstable isotopes has its own characteristic half life. Some half lives are several billion years long, and others are as short as a ten-thousandth of a second. On a piece of notebook paper, each piece should be placed with the printed M facing down.

geologic time scale and relative dating lab activity

This represents the parent isotope. The candy should be poured into a container large enough for them to bounce around freely, it should be shaken thoroughly, then poured back onto the paper so that it is spread out instead of making a pile. This first time of shaking represents one half life, and all those pieces of candy that have the printed M facing up represent a change to the daughter isotope. Then, count the number of pieces of candy left with the M facing down.

These are the parent isotope that did not change during the first half life. The teacher should have each team report how many pieces of parent isotope remain, and the first row of the decay table Figure 2 should be filled in and the average number calculated.

The same procedure of shaking, counting the "survivors", and filling in the next row on the decay table should be done seven or eight more times.

Activity 8: Application of Relative Dating, Radiometric Dating, and Geologic Time Scale

Each time represents a half life. Each team should plot on a graph Figure 3 the number of pieces of candy remaining after each of their "shakes" and connect each successive point on the graph with a light line. AND, on the same graph, each group should plot points where, after each "shake" the starting number is divided by exactly two and connect these points by a differently colored line.

After the graphs are plotted, the teacher should guide the class into thinking about: Is it the single group's results, or is it the line based on the class average? U is found in most igneous rocks. Unless the rock is heated to a very high temperature, both the U and its daughter Pb remain in the rock.

geologic time scale and relative dating lab activity

A geologist can compare the proportion of U atoms to Pb produced from it and determine the age of the rock.

The next part of this exercise shows how this is done. Each team is given a piece of paper marked TIME, on which is written either 2, 4, 6, 8, or 10 minutes. The team should place each marked piece so that "U" is showing. This represents Uranium, which emits a series of particles from the nucleus as it decays to Lead Pb- When each team is ready with the pieces all showing "U", a timed two-minute interval should start. During that time each team turns over half of the U pieces so that they now show Pb This represents one "half-life" of U, which is the time for half the nuclei to change from the parent U to the daughter Pb A new two-minute interval begins.

Continue through a total of 4 to 5 timed intervals. That is, each team should stop according to their TIME paper at the end of the first timed interval 2 minutesor at the end of the second timed interval 4 minutesand so on. After all the timed intervals have occurred, teams should exchange places with one another as instructed by the teacher. The task now for each team is to determine how many timed intervals that is, how many half-lives the set of pieces they are looking at has experienced.

The half life of U is million years.

Geologic Time Activities

Both the team that turned over a set of pieces and the second team that examined the set should determine how many million years are represented by the proportion of U and Pb present, compare notes, and haggle about any differences that they got.

Right, each team must determine the number of millions of years represented by the set that they themselves turned over, PLUS the number of millions of years represented by the set that another team turned over. Pb atoms in the pegmatite is 1: Using the same reasoning about proportions as in Part 2b above, students can determine how old the pegmatite and the granite are. They should write the ages of the pegmatite and granite beside the names of the rocks in the list below the block diagram Figure 1.