The purpose of this visit is to investigate lunar phases. After this lab, the students will be able to demonstrate and apply these concepts:

Transcription

1 Lunar&Phases& The purpose of this visit is to investigate lunar phases. After this lab, the students will be able to demonstrate and apply these concepts: The Earth rotates from counterclockwise as you look down at the Earth from the north pole. The sun seems to rise in the east, but we know that the earth s rotation is what causes the moon, the sun and the stars to appear to move in the sky. Using a model one way scientists better understand something like this. The moon is the earth s only natural satellite. It rotates once on its axis every time it revolves once around the earth, every 28 days. Using this knowledge, we can predict when will see each phase of moon in the daytime or nighttime sky. The moon doesn t create its own light, but it half of the moon s surface is always reflecting the sun s light. Depending upon the moon s location in its orbit around the Earth, we can see none of the lighted surface (new moon), the right half of the lighted surface (1 st quarter moon), all of the lighted surface (full moon) the left half of the lighted surface (3 rd quarter moon). The terms waxing and waning refer to whether the amount of lighted surface seen is becoming greater or smaller, respectively. Crescent and gibbous are used to describe phases less than a quarter moon or more than a quarter moon, respectively. The lesson plan begins with an introduction by the Science Leader. The students will divide into as many groups as the class has volunteers, up to five groups. At the end of the lab, the Science Leader will briefly review our conclusions. Teachers: Please divide students into groups once we are in the lab and we know how many volunteers are available to help. & Volunteers: Please read this material, and arrive at the lab promptly to familiarize yourself with the experiment. Your roll will be to ensure safety and assist the students as they complete the lab presented by the Science Leader. You will not be responsible for the class presentation, but it would be helpful if you read the information provided here before coming to the lab. Suggested Introduction by the Science Leader: Welcome to the Science Force Lab. This is a special time for you and our parent volunteers to investigate the exciting things you are learning in your classroom. The experiments you do during your Science Force visits are prepared and taught by your parents, and the equipment you use in this lab is purchased using the money from PTA. (Introduce yourselves and the parent volunteers.) Brainstorm with students You are studying lots of things about astronomy. Astronomy is the very first science ever studied. We are building on discoveries made by ancient scientists. Let s see what you have learned so far. (Just pick a few of these.)

2 1. What is our closest star? (the sun) 2. What is in the middle of our solar system? (the sun) 3. How many planets orbit the sun? (now eight) Try to name them in order. 4. Which planet is the largest? (Jupiter) 5. Which former planet is now considered a planetoid? (Pluto) 6. The big planets, like Jupiter, Saturn, Uranus and Neptune are made of mostly what? (gas, we call these Jovian planets) The smaller planets are made of mostly what? (rock, we call these terrestrial planets) 7. What are two ways that the Earth moves? (Revolves and rotates) 8. How many days does it take for the Earth to make one revolution around the sun? (365 ¼) 9. How many long does it take for the Earth to make one complete rotation (24 hours) 10. Is there anything that revolves around the Earth? (moon) 11. Does anyone know how many days it take the moon to make one complete revolution? (28 days) Do you know that it makes one complete rotation in 28 days too, so the same side of the moon is always facing us. We never see the backside of the moon. Instruction: In our lab today, we are investigating the phases of the moon. Scientists use models to better understand something that is too big to visualize, and our lab today is a perfect example of using a model. - Use a clip-on light or desk lamp and a ball to show how the sun shines on half of the ball s surface. Dim the class lights for a better effect. Whether it is the moon or the Earth, one-half of its surface is always illuminated by the sun. The moon doesn t make its own light. It only reflects the sun s light. - Choose one student to be the moon, and give them a ball. (about basketball-sized) Use the model and review revolution and rotation of the earth. Have them hold the ball straight above their head. Choose another student to be the Earth. Place them in the center of the room on a standing turn-table or sit-and-spin toy. For safety, the leader will always hold onto the Earth student so that they don t fall. The Earth student puts his/her head through the hole cut in the center of a framed blank art canvas, and holds the edges of the canvas with his/her hands. The canvas is labeled with E on the east and W on the west. The leader will rotate the Earth student from east to west (to the students left). The leader will explain, You are the earth. Imagine that your nose is a person on the Earth. Discuss how you can see half of the sky at all times. Rotate the Earth student, explaining the time of day sunrise, noon, sunset, midnight. Then add in the student who is the Moon with the basketball. Start them at the position of new moon, then revolve the Moon student around the Earth student, explaining the moon phases and that it takes 28 days for one complete lunar revolution. Although it is tough for fourth graders to comprehend, mention that while the moon is revolving once in 28 days, it is also rotating once on its axis. This means that the same side of the moon always faces the Earth. Discuss the phases of the moon and its position in the sky. For example a full moon is overhead at midnight, and a full moon sets at sunrise. Why can you sometimes see the moon during the day? Use the example that a third quarter moon is overhead at sunrise. Face the third quarter moon. Now look on your eastern

3 horizon and see the sun. Why won t we ever see a full moon at noon? It is because it is on the other side of the earth. If the moon is lighted on the right side, we know that each night it will have more of its surface lighted than the previous night. (We might say that it is getting bigger; in science we call that waxing.) If the left side of the moon is lighted, we know that the next night we will see less of its surface lighted. (So it will look smaller; in science we call that waning.) Remember that when you see the right side of the moon lighted, the moon is waxing, and the next night, more visible surface will be lighted. When the left side of the moon is lighted, it is waning, and the next night, less visible surface will be lighted. Discuss waxing and waning crescent and gibbous phases Now that we have used a classroom-sized model to help understand the Earth rotation and lunar phases, we are going to split into groups and use a desktop model to reinforce what you have learned. Divide the students into as many groups as you have volunteers, up to five groups. Ideally, there would be six or fewer students per group. Lunar Phases Game Instructions for the class volunteers: On each table is a game board, showing a model of the Earth, shaded half for day and half for night. The moon s orbit path is diagrammed, showing a spot for each of the 28 days of the lunar revolution. 1. Remind the students of what they have learned: - The sun is the center of our solar system - The sun produces light and other energy, and the Earth and moon only reflect the sun s light. The moon really doesn t shine. It just reflects, like a mirror. Use the example of a mirror. Does the mirror really have a face? No, it reflects your face. Half of the moon s surface always reflects the sun s light, but we can t always see the entire lighted half of the moon s surface. Sometimes we can t even see any of it at all a new moon. - Revolve means to go around something. The moon makes one revolution around the Earth every 28 days. Rotate means to spin on axis like a top. You can remember the difference because rotate has a T in it, like Top. Revolve has no T. The Earth revolves around the sun once in a year. The Earth rotates on its axis once a day. 2. Give each student a moon as their playing piece. The objective of the game is to revolve around the Earth more times than the other player in the group by the end of the playing time. 3. Everyone places their moon in the new moon phase (closest to the sun, along the trail marked black). Everyone rolls one die to determine who will go first (with the highest roll), and then play will proceed counter-clockwise.

4 4. The first player rolls both dice, and moves his/her moon counter-clockwise the same number of days along the path of the lunar orbit. Make sure that the night and day shading of the moon-playing-piece is oriented on the board to match the diagram shown on the playing board. The lighted side of the moon should always face the sun. 5. The board may be rotated so that the player can get their eyes down to look from behind the earth toward to the moon. This is to simulate what it would look like to look into the sky from the earth, looking to the moon overhead. Now the player must tell the group what the lunar phase is: New Moon Crescent Waxing or Waning 1 st Quarter Gibbous Waxing or Waning 3 rd Quarter Full Moon Check to see if the player identified the phase correctly by lifting the phase card that is the color that matches the trail extending toward the moon. If the student is wrong, then they must move their moon back as many days as the lowest numbered die. If they get the phase correct, they get a bonus question card. The adult volunteer draws a bonus card and reads the question to the player. If they don t know the answer, they can phone-aphase-friend and ask one player for help. If the phase-friend gets the bonus question right, then the two players split the bonus reward. Once a player gets a bonus question wrong, they forfeit the phone-a-phase-friend option. If they get the bonus question correct, then they get the reward indicated on the card. If they miss the bonus question, there is no consequence. 6. At this point, the first player s turn is over and the player to the right continues. Continue playing, as every player moves their moon around the orbit. Remind them as they move that each spot represents one day in the lunar orbit. After each player completes one orbit and returns to the new moon phase, then the player receives a Popsicle stick for completing one complete 4-week revolution. The player who completes the most revolutions during the playing period is the winner!

5 Conclusion: During the last five minutes, the Science Leader will ask the students to gather to review what the students learned about lunar phases. Setup: Demonstration: Sit-n-spin toy or rotation disk (from a gyroscope demonstration) 20 x 24 blank art canvas on a wooden frame, with a head hole cut in the middle Basketball or similar sized ball Clip-on light or desk lamp for the sun Game: (up to five tables, each with these supplies) One game board Six moon playing pieces One Earth 2 dice Set of bonus cards with question, answer, and reward Phase cards, color-coded to match the board Black New Moon Orange Waxing Crescent Moon Red 1 st Quarter Moon Blue Waxing Gibbous Moon Yellow Full Moon Purple Waning Gibbous Moon Green 3 rd Quarter Moon Pink Waning Gibbous Moon Georgia Performance Standards: S4E2. Students will model the position and motion of the earth in the solar system and will explain the role of relative position and motion in determining sequence of the phases of the moon. a. Explain the day/night cycle of the earth using a model. b. Explain the sequence of the phases of the moon Vicki Templet, all rights reserved. Duplication and transmission by electronic means is permitted for single use implementation in a public school environment, but only with permission of the author. Permission is never granted to post this document or any part of it on a webpage other than that of the author Duplication or transmission by electronic means is not permitted under any other circumstance. If you choose to duplicate, transmit, and/or implement any of the material provided herein, you accept the responsibility for assuring the accuracy and the safety of the activities and content of this material. In accepting this responsibility, you must also understand that this material is provided to you at no charge. No revenue or profit should ever be required in exchange for this material. Also in accepting this responsibility, you understand that this material is a collection of many ideas from many different sources. This document may have gone through many revisions as it has been passed from school to school, and the written descriptions may have come directly from sources that are not suitably referenced. It is therefore advised that this material be used at your own risk, and that you assume complete responsibility for the single-use application of the ideas contained herein. For questions or to receive a current version of this document, please feel free to contact Vicki Templet, info [at] science-force dot com.