Lesson 7 Overview. DRIVING QUESTION: How has Earth s temperature changed through time?

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Tobias Taylor
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global temperature has changed over time.

discover the pattern of natural climate cycling on Earth.

1 Lesson 7 Overview DRIVING QUESTION: How has Earth s temperature changed through time? LEARNING GOAL: Students construct a justified prediction to show how climate data from various sources reveal that global temperature has changed over time. TOTAL TIME: 100 minutes LESSON SUMMARY: Students will investigate the Earth s temperature through history to discover the pattern of natural climate cycling on Earth. They then use these data to predict what the pattern of temperature change would be from 1800 to present and into the future if the only influence is natural climate cycling. MATERIALS: Computers with Internet access LESSON 7: How has Earth s temperature changed through time? 1

2 BEFORE YOU BEGIN LESSON 7: Part 1 Have the video ready to show the class and worksheets of the graphs printed out individually for students. Students create a large, classroom timeline of Earth s temperature history, you may need to prepare an area with a large piece of papers or you could project it onto a writeable board. The timeline will be long, so an entire wall may be needed. Part 2 All activities for this lesson are online and are based on data from the Vostok ice core. Students review trends in graphs of temperature. Part 3 All activities for this lesson are online and are based on data from the Vostok ice core and Mauna Loa observations. Students review trends in graphs of temperature. LESSON 7: How has Earth s temperature changed through time? 2

Part 1: Understanding Milankovitch Cycles Earth s climate undergoes natural, cyclical changes. The primary forces behind these cyclical changes are Milankovitch Cycles (see: http://en.wikipedia.

3 Part 1: Understanding Milankovitch Cycles Earth s climate undergoes natural, cyclical changes. The primary forces behind these cyclical changes are Milankovitch Cycles (see: or news.discovery.com/earth/climate-myths-and-questions-part-ii.html for more). They are a result of changes in the wobble of the Earth on its axis, its elliptical orbit around the sun, and changes in the direction of the Earth s axis (see: These cycles are primarily responsible for the natural fluctuations observed in global temperature. In these activities, students observe these natural climate cycles through a record of Earth s temperature from 400,000 years before present and predict what global temperature should be in the last 150 years and into the future if only those natural fluctuations are at work. This provides the framework for understanding that the rate of temperature change in the last 200 years, and what is predicted for the future, cannot be explained by natural fluctuations. LESSON 7: How has Earth s temperature changed through time? 3

4 Part 1: Understanding Milankovitch Cycles Students use temperature data from Vostok ice cores to understand the impact of Milankovitch cycles on Earth s temperature. LESSON 7: How has Earth s temperature changed through time? 4

Part 2: Predicting Recent Climate under Natural Conditions Students review recent data on average global temperatures from ice cores and draw an estimated trend line that shows what

5 Part 2: Predicting Recent Climate under Natural Conditions Students review recent data on average global temperatures from ice cores and draw an estimated trend line that shows what the expected trend in Earth s recent average temperature would be if only Milankovitch cycles were influencing climate. LESSON 7: How has Earth s temperature changed through time? 5

would the pattern of Earth s temperature look like from 150 years ago until now if climate cycles were

6 Part 2: Predicting Recent Climate under Natural Conditions In this activity, students use information on average global temperatures from ice cores to create a prediction for the scientific question: What would the pattern of Earth s temperature look like from 150 years ago until now if climate cycles were only the result of natural climate cycles? LESSON 7: How has Earth s temperature changed through time? 6

7 Part 3: Actual Trends in Recent Temperature Students examine the actual trend in average temperature in the last 150 years and compare that to the predicted pattern from the previous activity. LESSON 7: How has Earth s temperature changed through time? 7

natural climate cycles explain increases in global temperature in

8 Part 3: Actual Trends in Recent Temperature Students use evidence presented in this Lesson to answer the Scientific Question: Do natural climate cycles explain increases in global temperature in the last 150 years? LESSON 7: How has Earth s temperature changed through time? 8

a. Do you think the function is linear or non-linear? Explain using what you know about powers of variables.

a. Do you think the function is linear or non-linear? Explain using what you know about powers of variables. 8.5.8 Lesson Date: Graphs of Non-Linear Functions Student Objectives I can examine the average rate of change for non-linear functions and learn that they do not have a constant rate of change. I can determine