# Daily Warm-Up Exercises

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Daily Warm-Up Exercises
Day 26 What are the three major types of rock? igneous, metamorphic, and sedimentary What's the main difference between the three rock types? The main difference is in how they form What do many of a rock's features depend on? Where and how the rock was formed. Daily Warm-Up Exercises 1 Daily Warm-Up Exercises 1

Contrasting Case Activity 4 Earth History, Investigation 6
Compare Time Scales Contrasting Case Activity 4 Earth History, Investigation 6 In this activity, students will compare two different kinds of diagrams that depict Earth’s history. The numeric scales (table and timeline) will help students begin to get used to starting with the present and moving backward into the past. The proportional scales (football field & clock) will help them begin to understand that the world we live in gradually emerged over a very long period of time, and that humans have only existed for a fraction of that time. Materials needed: •time scales (worksheets 15-18) •comparison tables (worksheets 19 & 20) Compare Time Scales Compare Time Scales

Age of Earth Earth’s history is measured in millions of years.
How much is a million? 1,000 times 1,000 1,000 thousand Earth was formed about 4,500 million years ago. How much is 4,500 million? 4,500 times 1,000 times 1,000 The purpose of this slide is to help students begin to comprehend the very large numbers involved in geologic time scales. If time permits, try some of the “Describe a Million” activities listed on page 225 of the FOSS manual. 4,500 thousand thousand 4,500,000 thousand Compare Time Scales Compare Time Scales

Human Life Humans first appeared about 200,000 years ago.
How much is 200,000? 200 times 1,000 200 thousand How does our age compare with Earth’s? 4,500,000 thousand 200 thousand = 4,500,000 200 This slide will help students begin to understand how old Earth is and how young the human race is by comparison. When you reduce the fraction comparing our age to Earth’s, you see that, for every year humans have existed, Earth has existed for over twenty thousand years. Tell students that the FOSS materials will say Homo sapiens appeared 40,000 years ago, which was what scientists used to believe. More recent fossil discoveries have led scientists to believe we actually appeared somewhat earlier. Additional note: All the other numbers in both numeric time scales match the numbers used in the FOSS materials. Geologists have since adjusted many of the period dates. You can find current information at = 45,000 2 = 22,500 years 1 year Compare Time Scales 4 Compare Time Scales 4

Numeric Scale 1 - Table Compare Time Scales

Complete Column 1 Table Timeline Paleozoic Era 4,500 mya 570 mya
Which part looks like it lasted longest? When did precambrian time begin? When did precambrian time end? How long did precambrian time last? When did the paleozoic era begin? When did paleozoic era end? How long did paleozoic era last? When did modern humans appear? Paleozoic Era 4,500 mya 570 mya 3930 million years 570 mya 245 mya Distribute the numeric comparison table (worksheet 19) and have students work in pairs to complete the first column. Answers will appear one-by-one on keypress. [The questions on the slide are shortened. See the student worksheet for the complete questions.] Before displaying the timeline, tell students that, in the next scale, history "flows" in a different direction. Encourage them to ask themselves, "If I want to follow Earth's history from past to present, how do I need to read this scale?" In the table, the past is at the bottom and the present is at the top. How will the next scale show history? 325 million years 200,000 years ago Compare Time Scales 6 Compare Time Scales 6

Numeric Scale 2 - Timeline
4,500 million years ago (mya) Quaternary – Modern humans appear 200,000 years ago Tertiary – Dinosaurs become extinct Cretaceous – Rocky Mountains are formed Jurassic – Flowering plants appear Triassic – First dinosaurs Permian – Great Extinction Pennsylvanian – First reptiles Mississippian – First amphibians Devonian – First insects Silurian – First land animals Ordovician – First land plants Cambrian – First trilobites Earth is formed; water appears on Earth’s surface; earliest, bacteria-like life appears Cenozoic Today 1.6 mya 66 144 208 245 286 320 360 408 438 505 570 Mesozoic Paleozoic Precambrian Time Students should easily see that, in the timeline, history "flows" from left to right. Compare Time Scales Compare Time Scales

Complete Column 2 Table Timeline Paleozoic Era Paleozoic Era 4,500 mya
Which part looks like it lasted longest? When did precambrian time begin? When did precambrian time end? How long did precambrian time last? When did the paleozoic era begin? When did paleozoic era end? How long did paleozoic era last? When did modern humans appear? Paleozoic Era Paleozoic Era 4,500 mya 4,500 mya 570 mya 570 mya 3930 million years 3930 million years 570 mya 570 mya 245 mya 245 mya Why are these called numeric scales? Students will probably recognize that “numeric” has to do with numbers. Both NUMERIC SCALES (table and the timeline) use numbers to show how many millions of years ago different things happened. 325 million years 325 million years 200,000 years ago 200,000 years ago Compare Time Scales 8 Compare Time Scales 8

Proportional Scale 1 - Football Field
Today (100 yards) START ZONE END ZONE Earth is formed (0 yards) Cenozoic Era (98.5 to 100 yds) Mesozoic Era (95 to 98.5 yds) modern humans appear (99.99 yds) Rocky Mountains form (97 yds) flowering plants appear (96.5 yds) first dinosaurs (94.5 yds) first reptiles (93 yds) first amphibians (92 yds) first insects (91 yds) first land plants (90 yds) first land animals (90.5 yds) first trilobites (88 yds) earliest, bacteria-like life appears (22 yds) water appears on Earth’s surface (11 yds) Great Extinction (94 yds) dinosaurs become extinct (98.5 yds) 10 20 30 40 50 60 70 80 90 Precambrian Time (0 to 87 yds) Paleozoic Era (87 to 95) Distribute the two proportional scales. Encourage your students to examine the football field and again ask themselves, "If I want to follow Earth's history from past to present, how do I need to read this scale?" Students should easily see that the football field is like the timeline, with the past on the left and the present on the right. Compare Time Scales Compare Time Scales

Complete Column 1 Football Field Clock precambrian time 0 yards
Which part looks like it lasted longest? When did precambrian time begin? When did precambrian time end? How long did precambrian time last? When did the paleozoic era begin? When did paleozoic era end? How long did paleozoic era last? When did modern humans appear? precambrian time 0 yards 87 yards 87 of 100 yards 87 yards 95 yards Distribute the proportional comparison table (worksheet 20) and have students work in pairs to complete the first column. Answers will appear one-by-one on keypress. [The questions on the slide are shortened. See the student worksheets for the complete questions.] 8 of 100 yards 99.99 yards Compare Time Scales 10 Compare Time Scales 10

Proportional Scale 2 - Clock
dinosaurs become extinct (11:39 pm) Earth is formed (midnight) Rocky Mountains are formed (11:14 pm) Today (midnight) START END flowering plants appear (11:12 pm) first dinosaurs (10:42 pm) modern humans appear (seconds before midnight) 12 Great Extinction (10:33 pm) 12 first reptiles (10:24 pm) 11 1 11 1 Ceno- zoic Era first amphibians (10:04 pm) Mesozoic Era first insects (9:52 pm) first land animals (9:46 pm) (10:42 - 11:39 pm) 10 2 10 2 first land plants (9:39 pm) water appears on Earth’s surface (2:40 am) Paleozoic Era (9: :42 pm) first trilobites (9:05 pm) 9 am 3 am 9 pm 3 pm Precambrian Time (12:00 am - 9:00 pm) Precambrian Time (12:00 am - 9:00 pm) 8 You will probably need to help your students understand this diagram. Tell them the two clocks represent one day, to show what Earth’s history would look like if it all happened within 24 hours. The left clock shows the first 12 hours, from midnight to noon, and the right clock shows the second, from noon to the following midnight. To make sure they understand this, you might have them think about their own 24-hour day, beginning last night at midnight. For example, point to midnight on the left clock and say, "Think about what you were doing last night at midnight." Point to 3 am and say, "Think about what you were doing at 3 o'clock this morning." Ask, "What time did you wake up this morning?" and point to the times students mention. This type of discussion will help students connect the clock representation to a day in their own lives. When you think your students have made that connection, go back and look at what the clocks show about Earth's history. Precambrian Time lasted from midnight last night, when most of us were sleeping, until 9 o'clock tonight, when most of us will be winding down at the end of our day. If Earth was formed last night at midnight, we wouldn't be here yet. All the plants and animals we're familiar with won't even start to appear until after 9 pm, and modern humans won't appear until seconds before midnight tonight. 4 8 4 earliest, bacteria-like life appears (5:20 am) 7 5 7 5 6 am 6 pm Morning Afternoon Compare Time Scales Compare Time Scales

Complete Column 2 Football Field Clock precambrian time
Which part looks like it lasted longest? When did precambrian time begin? When did precambrian time end? How long did precambrian time last? When did the paleozoic era begin? When did paleozoic era end? How long did paleozoic era last? When did modern humans appear? precambrian time precambrian time 0 yards midnight 87 yards 9:00 pm 87 of 100 yards 21 of 24 hours 87 yards 9:00 pm 95 yards 10:42 pm Answers will appear one-by-one on keypress. These are called PROPORTIONAL TIME SCALES because they show how different parts of Earth's history compare to the whole. Both the clock and the football field show that precambrian time makes up a huge proportion of Earth’s history. In comparison, the cenozoic era’s proportion is small, and human history’s is really, really tiny. 8 of 100 yards less than 2 hours 99.99 yards after 11:59 pm Compare Time Scales 12 Compare Time Scales 12

Compare Categories What can you learn about Earth’s history from the numeric scales but not from the proportional scales? That Earth was formed 4,500 million years ago. That it took thousands of millions of years for plants and animals to appear. Numeric scales are more precise than proportional scales. Compare Time Scales Compare Time Scales

Compare Categories What can you learn from the proportional scales but not from the numeric scales? It’s obvious that precambrian time is longer than all three eras put together You can easily see how young the human race is compared to Earth. You can see how far along in Earth’s history different things happened. Proportional scales make it easy to see how things compare. With the numeric scales, you can subtract and compare numbers, but it’s difficult to see how everything fits together. Compare Time Scales 14 Compare Time Scales 14

Compare Categories Could you include numeric information in the clock or football field? Add the date to each event or time division. Could you include proportional information in the table or timeline? Make the size of each box show how long that section lasted. In part 2, the class will work with a 45-meter timeline that includes both numeric and proportional information, with 1 cm representing 1 million years. In part 3, students will create miniature versions, with 1 mm equal to 1 million years. Although their timelines will be too small to include a lot of numbers, you might encourage them to incorporate at least some numeric information. Compare Time Scales Compare Time Scales

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