Classroom Activities
Investigation One
Lesson Description
In this activity, the students will discover that the rotation of the Earth produces day and night every 24 hours. They will also understand that the Sun is a bright star that illuminates light 360 degrees around.
Procedure
At this point, the students have already been observing the night sky. I will ask the students to share some objects that they have found in the night sky. When asking this question, the students always state that the Moon and stars are the two main objects in the night sky. Knowing this I will continue on to ask them if they are aware of what a star really is. I will record all responses on chart paper and read the story Our Very Own Star, the Sun. At the conclusion of the story, I will talk about how the Sun lights the day sky but then when we go to bed at night, what might happen to it.
I will then read a book titled Watching the Night Sky. This book closely relates to the above objective and will answer any questions or clarify any confusion that the students may have.
I will then show the students a globe with a sticker placed over the state of Delaware. The sticker will represent the people who live in Delaware. One student will hold the globe in front of the light source, facing the class with the sticker of DE facing the light source (Sun). I will point to the sticker and ask the students if it is day or night in Delaware. I will then have the student holding the globe turn it counter clockwise and ask the class what is moving and what is the Sun doing while the Earth is moving. I will ask the students what is happening to DE as the globe is turning and have them clarify at what points are day and night time. I will then explain to the students that it takes approx. 24 hours for the Earth to spin around one time. This corresponds with the 24 hours that we have in a day.
I will then read another story titled Day and Night. Class discussion will follow.
Summary
The students will be responsible for answering the following questions in their science journal:
How does the Earth move?
What does it spin around?
What is another name for spinning?
How long does the Earth take to spin one full time on its axis?
If it is nighttime in DE, where would it be daytime?
Assessment
The students will be given a handout after they are finished responding to the above questions. The hand out will be titled Day and Night. The question that the students will answer is the following: What causes day and night? In order for the students to receive full credit for their response, they need to write the following: Day and Night is caused when the Earth rotates. The Sun, which is located in the center of the Solar System, can only shine on one side of the Earth because it is shaped like a sphere. Light cannot reach all sides of a sphere at the same time. For the side of the Earth that is facing the Sun, it is daytime and the side not facing the Sun is nighttime.
Investigation Two
Lesson Description
In this activity, the students will understand that the size and shape of a shadow are a result of the Sun's position in the sky, because of the Earth's rotation, the Sun's position in the sky changes throughout the day and that the Earth is constantly moving and turning.
Procedure
We know that the Earth rotates around on its axis in a counter clockwise direction as seen from the northern hemisphere. This rotation of the Earth just makes it look like the Sun is moving across the sky. We can learn a lot about this by watching the shadows the Sun makes on Earth. I will ask the students if they have ever made a shadow and how the size and shape of the shadow changes.
With the light source back in the center of the room, one student will hold his/her hand in front if it casting a shadow of the hand on the board. Together we will discuss the shadows size, shape and position. I will then direct the student to alter the position of his/her hand but not change the shadow size and position. I will make sure that the students are aware that the light source is stationary.
For this experiment, the students will be studying how the shape and size of a shadow created by the Sun is a result of the Earth's rotation.
The students are going to be developing a Sun tracker that will be observed at multiple times throughout one school day. Students will draw a horizontal and vertical line across the middle of a large piece of white paper. They will write the cardinal directions on the paper. The students will then take modeling clay and stand a pencil straight up at the center of the paper where the two lines cross. The next morning at school, the students will go outside and find a flat space in an open area to place the tracker. Partners will use a compass to lay the tracker down according to the cardinal directions. At ten o'clock in the morning, the students will use a ruler and one colored crayon to draw a line directly on the shadow from the bottom of the pencil to the end of the shadow. They will use the ruler to measure this line in centimeters. They will record this on a recording sheet provided earlier in the lesson. The students will then repeat this procedure for the next four hours going outside at eleven, twelve, one and two o'clock. On their recording sheet, the students will have a list of questions that they need to answer after their observations are completed for the day: What made the shadow?, Did the shadow size change during the day?, Why do you think the shadow changed?
The next school day the students will review all the collected data and as a class will record the median length for shadow size in each of the time slots from the previous day. After all information has been displayed, I will ask the class to share observations that they may have about the numbers. Students will be noticing that the size of the shadows vary according to the time of the day. I will then ask them why they think that the shadow lengths changed throughout the day. The students should respond that since the Earth has rotated, this movement makes it look as if the Sun is moving across the sky. However, in reality the Earth's rotation makes the Sun's position change throughout the day.
Using the light source representing the Sun and the globe with the DE dot on it, I will demonstrate the Earth's rotation. After pointing to DE, the students will see that by turning the globe, the Sun appears to be in a different position in the sky throughout the course of the rotation.
Assessment
The students will complete a response sheet titled Daytime Shadows. This sheet addresses the following problem:
Taylor's class is learning about patterns of movement in the sky. By conducting an experiment using a Sun tracker, Taylor was able to prove that the Sun does not really move across the sky, it just appears to move.
The students will need to explain why Taylor's statement is true by answering what was really moving and how Taylor was able to prove her theory.
Investigation Three
Lesson Description
This lesson is designed for the students to understand that the Moon's phases change gradually and repeat themselves in a pattern, as well as the reflection of the Sun on the Moon's surface affects the appearance of the Moon and produces lunar phases.
Procedure
In earlier lessons, the students will have kept a Moon log tracking the phases of the Moon each night for about 30 nights. As a class, we have been keeping track of the daily log and have a chart displayed in the front of the room. I will draw the student's attention to this log and have them discuss their observations of how the Moon changed its appearance throughout the log. The students will share ideas of the patterns they see and possible explanations for why the Moon appears to change shape. In this experiment, the students will be completing an investigation to see why the Moon appears the way that it does in the night sky.
I will show the class a softball and have each student sit around the softball so that each student will see something different. I will turn on the overhead projector and position the ball so that we can only see one side of it, the side lit by the projector. The students will have a sheet in front of them in which they will draw a circle and shade in the part of the circle that they cannot see with their pencil and leave the lit part of the ball white on the paper. They are going to draw this in the same manner that they have been doing nightly for their Moon observations. Since the students are observing from all angles of the overhead, I will have three students approach the board to draw their observations for the class to see. Students from the far left, center, and far right of the room will come to the board. More than likely, their observations will be very different therefore posing the questions of how come their drawings are so very different yet we were all looking at the same ball.
Students will know that the ball represents the Moon in this investigation, with the overhead projector posing as the Sun. The Moon does not produce its own light, therefore reflecting light from the Sun. This can also be demonstrated by a flashlight and a mirror or bike reflector. The flashlight is the Sun and the mirror/reflector is the Moon. Just as the surface of the mirror/reflector reflects the light, the Moon's surface does the same. So, the light we see from the Moon at night is actually the Sun's light being reflected.
The students will gather in front of the overhead projector and I will explain the Moon's orbit around the Earth. Just like the Earth moves around the Sun, the Moon travels around the Earth. The ball represents the Moon and the projector is the Sun. But, we are missing the Earth in this model. Therefore, the students will hold the globe between the Sun and the Moon and position the softball directly in front of the light so the students see the fully lit side of the Moon. Moving the ball halfway around the Earth, the students are only seeing one side of the ball. After asking for observations that students should be able to share that as the ball is moving they are seeing less of the lit side of the ball. Stopping the ball where the students are not seeing any lit side, I will ask them what they see at this point. After replying that darkness is seen, I will begin to move the ball around the globe to its original position. The students should begin to share that the lit side of the Moon is increasing.
As the Moon moves around the Earth, we only see one side of it. Whenever we look at the Moon at night, we are always seeing the same side of the Moon. However, this is not the same side that faces the Sun, and is li up. Because of this, the Moon's shape changes. changes. These changing views of the Moon are called "phases". There are four main phases: new, first quarter, full, and second quarter. We have been viewing these phases throughout the month. The Moon goes through all of its phases in a month. Therefore, it takes the Moon only one month's time to travel around the Earth. Throughout the month however, these phases gradually change because as the Moon moves around the Earth we see different amounts of the Moon lit by sunlight.
The class will then break up into groups to explore the Moon's changing phases. Each pair of students will need a ball and a flashlight. One student will represent the Earth, the ball is the Moon, and the flashlight is the Sun. With a partner, one person holds the ball in front of their face as the other student stands behind shining the flashlight. The ball needs to be positioned so that you see the side facing you entirely lit by the flashlight. Then, the student will turn their body counter clockwise so that they are facing the light. Holding the ball in front, the lit side of the ball should now be facing away. Partners will then switch phases so that everyone has a chance to experience the changing phases of the Moon.
The next day I will read aloud The Moon Book. After reading, we will review the lesson described above. The students will discuss their findings as to what was happening when they moved the ball around their heads. After viewing the Moon log for clarification, the students will notice that the Moon's phases repeat themselves in a pattern. Students will realize that we can predict what phases are going to come at what times of the month. Since the pattern is cyclical, we know what phase will come each night depending on the phase the night before.
Assessment
Teacher made assessment will be distributed.
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