Lesson Plan 2: Phases of the moon

Transcription

1 Lesson Plan 2: Phases of the moon Ryan Wolfe EDTP 501 summer 2009 Date: July 2009 Age/Grade Level: 6 th Grade Number of Students: Number of Students with Special needs: (IEP, 504) Number of Gifted Students: (GSSP) Lesson Subject : Science Major Content: Earth & the Universe Number of Students with Limited English Proficiency: (LEP) Lesson Length (# of minutes): Three 50 minute classes Broad goal(s) of this lesson: to study lunar phases, their predictability, and related vocabulary Context In accordance with the JCPS Grade-Six Curriculum and Assessment Map, the previous unit dealt with the components of the solar system. Students are thus familiar with general astronomy terms used to discuss planets and moons. They also understand the basic layout of the sun-centric solar system and the fact that the moon orbits the Earth which in turn orbits the sun over the course of a year. This lesson specifically examine lunar phases as a way to discuss the Earth-moon-sun physical and orbital relationships with the students at the center of the experience (since lunar phases are only meaningful from the perspective of an observer on Earth). Subsequent lessons will examine how the Earth, moon, and sun interact to create lunar and solar eclipses. The effects of the moon on tides will then be used to segue into a broader discussion of gravity and other forces of the universe. Standards SC-6-EU-U-1: Students will understand that regular and predictable movements of the sun, moon and Earth are responsible for many observed phenomena on Earth, (e.g. day/night, year, moon phases, eclipses). The regular patterns of these phenomena can be predicted using data or models. SC-6-EU-S-2: Students will investigate, create and identify the limitations of models which can be used to substantiate and predict the actual results (e.g. moon phases, seasons, eclipses) of the interactions of the sun, moon and Earth

2 SC : Students will explain and predict phenomena (e.g., day, year, moon phases, eclipses) based on models/representations or data related to the motion of objects in the solar system (e.g., earth, sun, moon). Observations and investigations of patterns indicate that most objects in the solar system are in regular and predictable motion. Evaluation of this data explains such phenomena as the day, the year, phases of the moon and eclipses. Objectives Given the position of the moon and sun in the sky, students will correctly determine the phase of the moon at least 80% of the time. (DOK 2) On a written quiz, students will demonstrate knowledge of the moon s phases including vocabulary and graphical representations - by answering multiple choice questions with 80% or better accuracy. (DOK 2) Connections The direct instruction and discussion describes the regular motion of the moon around the Earth and demonstrates how this allows us to predict the phases of the moon as seen from Earth. This is part of standard SC-6-EU-U-1 from the Combined Curriculum Document. The discussion also uses a model of the Earth-moon-sun system in order to help students visualize the spatial arrangement of these bodies and the way in which light from the sun falls upon the Earth and moon. This ties in directly with SC from the Core Content for Assessment which says Students will explain and predict phenomena (e.g. moon phases) based on models/representation. In addition, it also allows students to identify the limitations of such models (SC-6-EU-S-2).

3 Objective Number Type of Assessment (formative or summative) Description of Assessment (format*) Depth of Knowledge Level Adaptations and/or Accommodations Objective 1 formative Discussion Guess the Phase activity 2 Partners Partial Notes & Diagrams Objective 2 summative Written quiz 2 Reference Notes & Diagrams Resources, media, and technology Classroom science textbooks, FOSS (Full Option Science System) workbooks, or reference documents: hardcopy, or online if sufficiently available in the classroom. Two-page, multiple choice quiz assessing knowledge of lunar phases. One-page Guess the Phase activity document. Material to model the Earth, moon, and sun 8 inch diameter ball (one with a blue-white swirl pattern is best) Standard baseball (painted white, with one side marked) A lamp or light with an exposed bulb to create sharper shadows Optional: 20 foot pre-measured string to demonstrate distance to moon Images (possibly in Power Point) to help illustrate lecture and discussion Earth_Moon_Distance.jpg Earth_Moon_Scale.jpg Far_Side.jpg Phases_Diagram.jpg Moon_Orbiting_Screenshot.jpg Moon_Orbiting_Screenshot_2.jpg Sun_Earth_Moon.gif Full_Moon.jpg YouTube video of animated phase diagram

4 Procedures Step 1: Introduce / Engage: The purpose of this lesson is to explain the phases of the moon so that students can understand, predict, and name them. This is also an exercise in 3D visualization as the arrangement in space of the sun, moon, and Earth determine where and how the moon appears in the sky. To begin, display a full-screen image of the moon (Full_Moon.jpg or something similar) to gain attention and to make it very clear what you will be talking about during this lesson. All students should have some prior knowledge concerning the moon and the fact that it s appearance changes from night to night. Begin the lesson by drawing upon this background knowledge and focusing attention with questions like the following: What phase was the moon in last night? The answer varies depending on where it is in it s 30- day cycle. It is quite possible that the moon was not visible at all, or only during the wee hours of the night, and so there may not be a good answer to this question. At the very least, it gets them trying to visualize the moon from their point of view. Most of the time part of the moon is lit up and part is not. Why is this?. The answer is because sunlight falls on half of the spherical moon leaving the other half dark. From Earth, we usually see some of the lit part and some of the unlit part. Half the moon is ALWAYS illuminated, but we only see part of the illuminated half from Earth the amount of the lit half we can see is the phase. A common misconception is that the Earth s shadow causes the darkness, so this is a good time to point out that the moon would appear the same even if the Earth were gone. Why do the phases of the moon matter to us? The phases of the moon have been used to set up calendars ( month = MOON th ), determine harvest times (harvest moon = enough light to keep working through the night), and religious celebrations. Hunters and fishermen know that the phase of the moon affects animal behavior. In folklore, the full moon is associated with werewolves and insanity ( Luna = Latin name for the moon and is the root for lunatic ). Inform students that by the end of this lesson they will be able to figure out the phase of the moon given nothing but the location of the sun and moon in the sky. They will also be able to name the phases using the proper scientific vocabulary.

5 Step 2: Activities / Explore / Explain: Model the Earth-moon-sun system using a large (8-inch diameter) ball, baseball, and lamp. The large ball (available at Wal-Mart for about a dollar) represents Earth. The baseball is the moon, and the lamp (or other light source) creates the sunlight for our model. Turning off the classroom lights may help. You may also want to put a mark (like an X ) on one side of the baseball and then have that mark facing towards Earth no matter where the ball is in its orbit. This models how the Moon (being tidally locked) always keeps the same side facing us. It s not a primary objective for the lesson, but it bears mentioning as it explains why the face of the moon always looks the same to us aside from the phase changing. Many moons in the solar system orbit their parent planets in a similar fashion which may have come up in the previous lesson. As an aside, the shadows created using this model will not be nearly as sharp or dark as those you see on the real moon. This is because the classroom has air in it. This scatters the light, making the shadows fuzzy and partially illuminating even the dark side of objects. There may also be extra light coming in from windows and so forth so point out that this is just a rough approximation to help with visualizing the system. There is no air between the real sun and moon, so the moon has a sharp, very dark, shadow on the side away from the sun. The baseball and larger ball are approximately to scale. Display the Earth_Moon_Scale.jpg image to reinforce this. Use this model, in conjunction with the Phases_Diagram.jpg to demonstrate how the phase of the moon changes from our point of view as the moon orbits around the Earth. The diagram also contains the key vocabulary for the lesson: New Moon phase when the side facing us is unlit. Moon is not visible in this phase. Crescent less than half lit First/Third Quarter half of the moon facing us is lit up Gibbous more than half, but less than fully lit Full Moon fully lit Waxing illumination increasing (from New up to Full) Waning illumination is decreasing (from Full back down to New) Be sure to note how a quarter moon is actually half illuminated from our point of view. The quarter notation refers to the fact that the moon is a quarter of the way through it s cycle. There is another quarter moon when the moon is 3/4 th of the way through it s cycle.

6 Below is a good summary of the information to be imparted during this part of the lesson. By observing the Moon over a period of several weeks, one will notice that the Moon rises and sets at different times each night, and that there is a regular progression through lunar phases. In days, the Moon progresses through one lunar cycle and will vary between being a completely dark new moon and a fully illuminated full moon. The lunar phases are caused because the orbit of the Moon around the Earth will vary the Moon s position in relation to the Sun. Half of the Moon is always lit by the Sun, but the portion that we see will change depending on where the Moon is in its orbit. The cycle begins at new moon. Because the Moon is in the same part of the sky as the Sun, the illuminated half of the Moon is not facing us and is not visible. During new moon, the Moon rises and sets at the same time as the Sun, and is therefore in the sky during the day. There is then a progression through the growing crescent phase until we see the right half illuminated; this is known as a first quarter moon. After the first quarter phase, there is another progression, this time through the waxing gibbous phases. The Moon becomes full about 15 days after the new moon. During a full moon, the Moon is opposite the Sun and is fully lit when viewed from Earth. The Moon rises at sunset and sets at sunrise when it is full, so the Moon is always visible in the night sky while full. The Moon then begins to wane through another gibbous phase until it reaches its next phase called last or third quarter moon, and again proceeds through another crescent phase, ultimately returning to the new moon almost 30 days later. Borrowed, with slight modification, from: n4/phasesmoon.html The following video (if available) is an animated version of the phases diagram: The image Moon_Orbiting_Screenshot.jpg is a screenshot of this video and can be used as an example if the video is unavailable. The video is a top down view and, like the diagram, shows the moon going behind the Earth but still being full (see Moon_Orbiting_Screenshot_2.jpg ) Pose the following question: How can the moon appear fully lit if it is behind the Earth? Shouldn t it be dark because it is in the Earth s shadow? the moon is actually much further away than these diagrams show, and it s orbit is tilted a bit so it rarely passes through Earth s shadow. Note, however, that a lunar eclipse can only occur during a full moon (and a solar eclipse only during a new moon) but we ll talk about that more in the next lesson. To demonstrate the distance to the moon using the model, place the baseball approximately 20 feet away from the larger ball. Pre-preparing a 20 foot length of string can make this easier, and can also involve a students to hold the string and ball. This setup demonstrates the real distance to the moon in the scale of our model, and should make it clear how the moon avoids the Earth s shadow with even a little tilt in its orbital plane (it s about 5 degrees off of the ecliptic). Image Earth_Moon_Distance.jpg also illustrates the actual distance.

7 Other Interesting Bits Work these in where appropriate: The moon orbits such that the same side is always facing the earth. This is really common for moons because the gravity of the (much larger) parent planet locks them into this position like a ball on a tether. We never see the far side of the moon from Earth (show Far_Side.jpg). It is sometimes called the Dark Side of the Moon, but that is wrong. It is lit up just as much as the near side we just don t see it from Earth. The moon rises about 50 minutes later each night. This is because the moon goes around the Earth in about 30 days so it s about 1/30 th of a day further along each time it rises. Stress that the moon s orbit is very predictable (like all of the major bodies in the solar system). The time estimate for this lesson is one 50 minute class period to cover everything up to this point, and another 50 minute class period to cover Step 3 below. The assessment would then be done on the following day, perhaps after a brief review. Step 3: Elaborate: During this section of the lesson, the goal is to get the students involved and let them make some predictions about the phase of the moon given its location in the sky relative to the sun. In making these predictions they will also practice using the vocabulary for describing lunar phases. Show the image Sun_Earth_Moon.jpg and ask What phase is the moon in? This is a tricky question because the image is from a vantage point behind the moon. From the point of view of the picture, the moon is almost new (a thin crescent is illuminated). From the Earth, however, it would appear full. The key point is that the moon is directly opposite the sun with the Earth in between. This means the moon is full as seen from Earth. The angle from sun to Earth to moon always determines the phase of the moon.

8 Display or hand out the document Moon_Phase_Guess_the_Phase.doc and explain that given any two of the following, you can determine the third: 1) Sun s location in the sky 2) Moon s location in the sky 3) Phase of the moon We will pick the first two items and then guess the phase from that information. To demonstrate this, have one student pick the sun s location from the first table; then have a second student pick the moon s location from the second table. Given these parameters, a third student can determine the phase of the moon (consider picking a fourth to agree or correct). As time allows (or for particularly interesting combinations), have the student come up and show the current arrangement using the model or the video animation. Students can be picked randomly or using any method you prefer. The goal is to keep the students involved by letting them have some input. The first two choices are also safe in that there is no wrong answer so these may be guided towards students who would benefit from that fact. The Guess the Phase document has a diagram at the bottom to help with the visualization process (though it might be necessary to review how a full circle is 360 degrees). The key to using it is to realize that the angular separation between the sun and moon in the sky determines the phase of the moon as seen from Earth. If there is no separation (that is, if the sun and moon are right near each other in the sky), then it is a new moon (and probably not visible). 45 degrees of separation is a crescent, 90 is half a moon, 135 is gibbous, and 180 degrees yields a full moon. It doesn t matter where the sun is, just how many degrees there are between it an the moon. To start, consider allowing only 0, 90, or 180 degrees (sunrise, noon, or sunset) for the sun s location as these are the easiest spots from which to figure out the phase. Once students can do that easily, then increase the difficulty by letting the sun be at any of the 6 possible positions. You may also consider letting students pick from any of the two tables then the third student has to fill in the missing piece of data. This would be a good option for more advanced learners. Depending on the class, there are alternate ways in which this activity could be presented to increase participation. The default teacher lead question and answer - is applicable in most situations and is the easiest to implement. Guess the Phase could instead be used as a group exercise by breaking the class into groups of three with students taking turns picking locations and guessing phases within their groups (and maybe keeping score just for fun). The tables include a Random column so that picking locations by chance is also an option. Another

9 possibility is to use this as a more formal assessment by having two students pick sun and moon locations as usual, but then having everyone answer by writing down the phase on a sheet to be turned in, or on a personal whiteboard to be displayed. Note that determining waxing from waning is not necessarily part of this Guess the Phase exercise. The moon is Waxing (gaining lighted area) if it is up mostly during the day and Waning (growing less illuminated) if it is up mostly during the night. Guess the Phase emphasizes the day time and so most answers will technically be Waxing moons if that level of detail is required. Also note that in real life you could use your arms as an ad hoc protractor to figure out the angle. Point one hand at the sun and the other at the moon. The angle you make tells you the phase of the moon as above (ie. 180 degrees means the sun and moon are on opposite horizons and the moon is full). This is useful information for kinesthetic learners, and might even be a good technique to employ during the Guess the Phase exercise. At some point during this section of the lesson, ask Is the phase only meaningful when viewed from Earth? The phase of the moon is indeed only meaningful given a point of reference (and Earth is the only meaningful viewpoint in this particular system). Note that the phase will look pretty much the same from anywhere on Earth at a given moment. If the moon is full over L.A., then it is going to look full from New York (though it will be in a slightly different part of the sky). Special Considerations This lesson combines traditional lecture and discussion with a physical model and various graphics and animations. This should appeal to several different learning styles. English Language Learners with a given fluency may be seated near a like student where feasible as having another person with a fluent language in common may facilitate participation. Non-English conversation should be acceptable so long as it is on task and does not become exclusionary with regards to the rest of the class. Translations of vocabulary words, and labeled images illustrating key concepts, can also be provided. While there isn t any group work in this lesson, the Guess the Phase activity can be expanded to include partners or teams. Discussion with nearby partners should also be encouraged in order to promote a feeling that this is a team effort. A possible accommodation for students with special needs is to provide an outline of the notes, with key words left blank. This will allow students to follow along in an organized manner, but still

10 require them to pay attention in order to fill in the key words. They may also be allowed access to these notes during the assessment. Possible Extensions There are many extra activities that can be done relating to the moon. These can be used to support varied learning styles or considered as accommodations for some students an alternate way to show understanding of this content. If implementing this extension, allow each student to choose one of the following longer-tem assignments: 1. Find or create a painting or drawing showing the sun and moon in the sky. Explain briefly whether (and why) the phase of the moon is correct given the location of the sun and moon shown. 2. Over the course of a week, sketch the phase of the moon each day or night that you can see it. Note the rising and/or setting time if possible. 3. Write a poem of reasonable length concerning the moon and draw or find a supporting piece of art. 4. Create a poster (hard copy or digital image) commemorating a historic mission to the moon (landing, orbiting, or other important event). Use images and text from online research. 5. Research folk tales or ancient beliefs about the moon and write a one page report. 6. Come up with your own moon-related project and clear it with the teacher. Allow a week for these to be completed and then have each student briefly present their project to the class. This would also be a good time to quickly review the lesson and key points.

11 Step 4: Closure / Evaluate: The summative assessment covering the phases of the moon takes the form of a written quiz with several multiple choice questions. This quiz is given at the start of the class period following the lesson so that some study and long-term recall is required. The summative assessment is to be done individually and without reference material of any sort (unless part of an accommodation for a student with special needs). Students not proficient in English may be accommodated by being given a list of vocabulary in a language with which they are fluent, or they may be allowed to use a translation reference. All students should be given ample time to finish the quiz as speed-ofrecall is not being assessed here. The quiz is worth 20 points. Once all students have completed the quiz, go over the answers and clear up any remaining questions or concerns regarding the lesson. Review that we have learned what the phases of the moon are, why they occur, and how to predict them. Explain that the next lesson will discuss lunar and solar eclipses using the visualization skills and model from this lesson to discover why eclipses occur (and why they don t occur more often).