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Debra Kosloski Earth’s Tilt and Its Effect on Light and Seasons Grade 6 Science (Two 60 minute Class Periods) Scientific Investigation, Reasoning, and Logic 6.1 The student will plan and conduct investigations in which a) observations are made involving fine discrimination between similar objects and organisms; e) hypotheses are stated in ways that identify the independent (manipulated) and dependent (responding) variables; f) a method is devised to test the validity of predictions and inferences; i) data are organized and communicated through graphical representation (graphs, charts, and diagrams); j) models are designed to explain a sequence; and k) an understanding of the nature of science is developed and reinforced. Interrelationships in Earth/Space Systems 6.8 The student will investigate and understand the organization of the solar system and the relationships among the various bodies that comprise it. Key concepts include: d) revolution and rotation; e) the unique properties of Earth as a planet; g) the relationship of the Earth’s tilt and the seasons; Instructional Objectives: Appropriate instructional objectives should be included here. The objectives should specify measurable student outcomes. The student should be able to use a physical (globe and lamp) or pictorial (diagram) model to: 1) Explain how the relationship between the tilt of Earth's axis and its yearly orbit around the sun produces the seasons. 2) Explain how the Earth’s tilt on its axis changes the length of daylight received by Earth’s northern and southern hemispheres. 3) Explain how the tilt of the Earth’s axis and its yearly orbit around the sun changes the amount of direct sunlight received by Earth’s northern and southern hemispheres. 1 Debra Kosloski . Lesson Segment & Time Est. Day 1: (60 minute class period) Introductio n (Predict, Explain) (10”) Body (Observe) (Explain) 15” Materials Instructional Sequence Assorted globes of different size, Warm-Up: (10 minutes) Predict: Elicit Students’ Ideas: age, manufacture, *An assortment of Earth globes are displayed on the teacher’s lab table as the etc. (one for students enter the classroom. each student lab table) 1) Students will use their lab notebooks to draw a picture of the object as displayed as a globe. A lamp or 2) Ask the students to write down what they think these globes represent. (A flashlight for model of the Earth). each lab table. 3) Students are asked to list observations (similarities and differences) of the globes. (color representations, location of equator and poles, size, shape, Student lab position of the Earth on each display, etc.). notebooks 4) Ask students to write what is the purpose of a globe. (Students may say that it represents our Earth, decorate a classroom, help us to get a better understanding of our Earth, a model, etc.) 5) Predict what effect the tilt of the Earth, as displayed on each of the globes, has on the amount of direct sunlight received by the northern and southern hemispheres as the Earth makes its revolution around the sun and record predictions in lab notebook. A lamp or flashlight for each lab table. Teacher/Student Actions Include brief description of what teachers and students will be doing during each activity/segment of the lesson. Teacher: Visits each student to be sure the student understands the activity and prompt students who may be confused. Students are applying their observation skills to draw a picture of Earth as a globe and to answer the questions about the globe. Lesson: Explain: (10 minutes) Discuss students’ predictions: S. share predictions/explanations in a class discussion. Make sure to value all ideas. Discuss s. predictions and rationales and have s. discuss, given the range of predictions, which might be most reasonable. Discuss student responses to above warm-up. Students will conclude that although the globes may be of various size and color scheme, they all represent our earth, are spherical and have a “tilt” of approximately, 23°. The Earth globe is a model of our Earth and the tilt is always pointed toward the north star as the Earth revolves around the sun. Ask the students if their original drawings included the Teacher records student 2 Debra Kosloski Lesson Segment & Time Est. Materials Student lab notebooks Hands On 10” A lamp or flashlight for each lab table. Student lab notebooks Instructional Sequence Teacher/Student Actions tilt? Add the north star, Polaris, to the picture and label it. Although the Earth is observation (similarities spherical, did you notice that it can be divided into two halves? These are called and differences) on the “hemispheres”. “Hemi” means “half”, and “sphere” is a ball-like shape. The whiteboard or document Northern Hemisphere, where the United States is located, is above the equator. camera. Australia is in the Southern Hemisphere, below the equator. Can you name any Students: Share the data other land masses that lie in the Northern Hemisphere? In the Southern that they observed and Hemisphere? Let’s see what happens in each hemisphere as the Earth makes its add to their lists in their revolution around the sun. Do the areas of the Earth receive the same amount of lab notebooks direct sunlight throughout the year (one revolution around the sun) – being sure to Students add the keep the north pole always pointed to the North Star, Polaris? Let’s see! following words to their dictionaries: Hands On Lab: 23° Observe: (10 minutes) S. conduct the investigation, make observations, etc. Direct light Distribute a globe and light source to each lab table. Keeping the globe tilted Earth toward a point in the classroom that will symbolize the north star, Polaris, the Earth’s tilt students will work in small groups to maneuver the globe around the light source. Equator The students will notice that light travels in a straight line from the source. Globe Students will observe that the surface of the Earth is curved. Light will not wrap Hemisphere around the Earth, but if it hits a curved surface, the light will be “spread” over a Model larger area. They will notice which hemisphere is tilted toward and away from the Northern sun during various points of the Earth’s revolution. Are there times when the Hemisphere Northern Hemisphere is tilted toward the sun? Which direction does the Southern North Star, Polaris Hemisphere point at that time? Does the Southern Hemisphere ever tilt toward Southern the sun? Where is the Northern Hemisphere tilt at that time. When does each Hemisphere hemisphere receive the most amount of direct sunlight? When does it receive the least sunlight? Are there ever times when neither hemisphere tilts toward the sun? Which hemisphere gets the most sunlight at those times? What seasons Teacher monitors group occur when neither hemisphere tilts toward the sun? activities and assists Lab Explain: (15 minutes) (Small groups) S. discuss observations and their Groups in moving the explanation for these observations in small groups then develop a written globes in a explanation counterclockwise orbit Students will discuss what they have observed with their small groups and around the light source 3 Debra Kosloski Lesson Segment & Time Est. Materials Instructional Sequence now record their observations; including a drawing of the Earth at 4 major positions (Where the Northern Hemisphere receives the most direct sunlight, the least sunlight and the two locations where neither hemisphere is tilted toward the sun, so that they receive about the same amount of sunlight). Closure (Explain, con’t) 20” Illuminated Model of the Earth and Sun Illuminated Model of the Earth and Sun Explain/Debrief (20 minutes): Whole-class discussion of small group observations/explanations using a Illuminated Model of the Earth and Sun. Provide the scientific explanation to students. 1. What position of the Earth provides the most direct sunlight to the Northern Hemisphere? What season is occurring in the Northern Hemisphere at that position? What is happening in the Southern Hemisphere at this time? What season are they experiencing? 2. If you were to move the globe one fourth of its revolution around the sun, going counter clockwise, which hemisphere receives the most direct sunlight? What season is the Northern Hemisphere experiencing? The Southern Hemisphere? 3. Now move your globe so that it is now halfway around the orbit and note which hemisphere, if any, is tilted toward the sun now? Where is the other hemisphere tilted? Which season is occurring in each hemisphere? 4. Move the globe so that it is ¾ of the way around the “sun”. Which hemisphere is receiving the most direct sunlight? 5. When did the two hemispheres receive the same amount of direct sunlight? This was when neither hemisphere was tilted toward the sun. During the spring in the Northern Hemisphere (fall in the SH) and again when the Northern Hemisphere was having its fall (spring in the SH). There are two days during the year when each hemisphere gets an equal amount of day and night. We call that an Equinox. The Northern Hemisphere has its Spring (or Vernal) Equinox on March 22, and its Fall or (Autumnal) Equinox in the fall on September 22. What do you think is happening in the Southern Hemisphere when the NH experiences its equinoxes? 6. During the summer, the days get longer until June 21st, the longest day and shortest night in the Northern Hemisphere. During the winter the days Teacher/Student Actions (the “sun”). Students work in lab groups to simulate the Earth’s revolution around the sun using a globe and a lamp. They collect data on their observations of where the most “direct light” strikes the globe as it orbits. Students will include a drawing of the Earth and “sun” where the Northern Hemisphere would be experiencing Winter, Spring, Summer and Fall. Teacher demonstrates the revolution of the Earth as it orbits the sun using a Trappensee Brand Illuminated Model of the Earth and Sun. Students use their observations/notes to answer the questions to the right and summarize their understandings. Students include the 4 Debra Kosloski Lesson Segment & Time Est. Materials Instructional Sequence continue to get shorter until December 21st, when the NH has its shortest day and longest night. 7. Label your drawings with the seasons and the equinoxes for NH and SH. Assessment 5” Paper & Pencil Teacher/Student Actions following words in their lists w/ definitions: Autumnal (Fall) Equinox Equinox Vernal (Spring) Equinox Cool Down: (5 minutes) Exit Ticket- 1. Why does the Earth experience seasons? 2. Draw a sketch of the Sun and the Earth when the Northern Hemisphere is experiencing its summer. What is the Southern Hemisphere experience when Earth is in this position? 3. Which area of the Earth experience less variation of climate during its seasons? 4. Why does this area have less variation in its seasons? Students write/draw their responses on a half sheet of paper. Teacher collects assessment as students exit the classroom. Total Time =60” Day 2: (60 minute class period) *Flashlight (one for each lab 5 Debra Kosloski Lesson Segment & Time Est. Introductio n (Predict, Explain) (5”) Body (Observe) (Explain) 15” Hands On 20” Materials pair) *Student Science notebooks Instructional Sequence Warm-Up: (5 minutes) 1) What do you predict will happen if you take the beam of a flashlight and point it straight down on a sheet of white paper? 2) What do you predict will happen if you take the beam of a flashlight and shine it at an angle onto your white paper. 3) Using a flashlight, act out the two scenarios with your partner. Trace the shape of the beam of light and label it as straight on or at an angle. 4) Is the shape of the beam of light that you drew on the paper the same or different? Why? Laptop or IPad Cart Lesson: (15 minutes) Technology: Ecliptic Students will work in Pairs to explore the Computer Ecliptic Simulation to see Simulator how the angle of the sun’s rays changes throughout the year. They will notice http://astro.unl.e that as the angle of the sun’s rays changes from the “normal” of straight on, the du/naap/motion ray’s light is spread over a wider area. The same amount of light is received, but 1/animations/se due to the angle less light and heat energy from the sun is received. Students can asons_ecliptic.h observe as the website travels through all twelve months and/or manipulate the tml program to visit individual months. AIMS: Pasta Parallels http://www.gcis dk12.org/cms/lib/ TX01000829/C entricity/Domai n/75/MS%208 %20Grade%20%20OL%20and %20PAP/8.4%2 Hands On Activity (30 minutes) 1) Students will create a Key for their graph that associates the number of pasta strands for the width of the sun beam reaching the earth. 2) Students will place the pasta strands side by side onto each sunbeam to determine the width of the beam. 3) Students will color the beam on their graph to represent the Graph’s Key. Complete the graph 4) Students will cut out the circle that represents our Earth and using the brass fastener, attach it to the graph Teacher/Student Actions Teacher visits each pair of students to be sure that they understand the positioning of the flashlight beam onto the paper. Students manipulate a flashlight to simulate the shape to the beam as it is aimed perpendicular to the paper and at an angle (direct and indirect light). Teacher models the completion of the key as the students complete their own key. Students will apply teacher model to the completion of their own Key. 6 Debra Kosloski Lesson Segment & Time Est. Materials Instructional Sequence Teacher/Student Actions 0Weather/Pasta %20Parallels.pd f Materials: 1)Pasta Parallel packet for each student 2)Several Strands of Thin Pasta at each lab table. 3)Colored Pencils or crayons 4)scissors 5)Brass fastener Closure (Explain, con’t) 15 “ Explain (continued): Students will manipulate the Graph that they created to simulate which hemisphere of the Earth receives more direct or indirect sunlight during the year. 1. What do you notice about your ray graph? 2. On June 21, where are the most direct rays of the sun? Where are the most indirect rays? What seasons are the Northern and Southern Hemispheres having then? 3. On December 21, where are the most direct rays of the sun? Where are the most indirect rays? What season are the Northern and Southern Hemispheres having then? 4. How is the slant of the rays related to the seasons? 5. What kind of clothes do you wear in June? If you were to travel to Australia in June, what kind of clothes would you take? Students will manipulate their Pasta Parallel graph in order to answer the questions. Teacher will visit each lab pair to insure that they understand what is being asked and that they are manipulating the graph correctly. 7 Debra Kosloski Lesson Segment & Time Est. Assessment 5” Total time: 60” Materials Instructional Sequence 6. Find the central, most direct rays. What is its farthest point north? What is its farthest point south? What might the climate be like in this area? Why? 7. What happens to day (or night) in the Arctic (or Antarctic) Circle as it goes through the different seasons? 8. If the Earth were not tilted, how would that affect us during the year? 9. What are you wondering now? Cool Down – Exit Ticket 1) Explain how the relationship between the tilt of Earth's axis and its yearly orbit around the sun produces the seasons. 2) Explain how the Earth’s tilt on its axis changes the length of daylight received by Earth’s northern and southern hemispheres. 3) Explain how the tilt of the Earth’s axis and its yearly orbit around the sun changes the amount of direct sunlight received by Earth’s northern and southern hemispheres. Teacher/Student Actions Students will be able to answer the questions independently. Teacher will collect student responses as they exit the classroom. 8