Food Chain of an Owl

Exam Tip on Measurement

UPSR - Solar Eclipse

Summary of Activity:

This lesson provides students with a concrete model of the Sun, Earth and Moon and their interaction during a solar eclipse. Students observe and manipulate the 3-D model and simulate the movement of these bodies during an eclipse. 

 Duration of Activity:

40 minutes.

Materials:

Earth globe (approximately 14" to 16" in diameter)

String

Paperclip

Frame or ceiling hook (from which to hang the globe)

Yardstick

Tape

Thread or monofilament line

3-inch Styrofoam ball

Lamp with a 200 watt bulb, shade removed and extension cord

Work sheets

Teacher Preparation:

Allow 20 minutes to locate and prepare materials, and set up the eclipse demonstration model and copy work sheets.

Work Sheets:

"Solar Eclipse" Work Sheets

    Objectives:

Students will understand that during a total solar eclipse:

The Moon is between the Earth and the Sun.

The Moon blocks the Sun’s light from reaching the surface of the Earth.

The shadow cast by the Moon covers only part of the Earth’s surface.

The Moon’s shadow moves across the Earth.

It becomes dark during the day.

Total darkness only lasts a few minutes.

Procedure:

Preparing the model

1.       Choose a location in the classroom with ample room (approximately 10’ x 10’) to demonstrate the eclipse model. Students may want to sit in a circle or semicircle with the model in the middle.

2.       Hang the Earth globe from the ceiling or framework, so that it hangs about 24" to 30" above the floor. A paperclip with one side bent into an "L" shape will support the globe. Tie string to the paper clip loop, and insert the "L" into the globe’s small hole at top (North Pole point).

3.       To a chair or other sturdy object, tape a yardstick so it extends parallel to the floor.

4.       Cut a short length of thread or monofilament and attach the 3-inch Styrofoam "Moon" ball to one end of the thread. Tie the other end to the yardstick.

5.       Set the suspended Moon ball 12" - 15" away from the Earth globe.

6.       Place the lamp near the hanging "Moon" ball and globe so that the "Moon" casts a shadow on the Earth globe. (See photo)

7.       Have students create an individual K-W-L chart or do this as a whole-class activity.

K — What the students know about the solar eclipse.

W — What they want to learn about the solar eclipse.

L — What they have learned about solar eclipse.

Teaching with the model

a)      Turn on the lamp and turn off the classroom lights to make the shadow more visible.

b)      Slowly turn the Earth globe counterclockwise and begin your discussion of the model by asking students to identify the Sun, the Earth and the Moon.

c)       Ask students to use the model to explain how an eclipse takes place.

d)      Turn the globe so that the "Moon’s" shadow is covering your city. Remind students never to look at the Sun, but ask them to describe how things might look in their city during a total solar eclipse.

e)      Point to the KWL chart used in the previous introductory lesson and review what students contributed. Ask if students have learned anything new to add the chart.

Possible points to elicit in your discussion of what happens during an eclipse–

The Moon is between the Earth and the Sun.

The Moon blocks the Sun’s light from reaching the Earth’s surface.

During the daytime it becomes dark on a small part of the Earth.

The shadow cast by the Moon only covers part of the daytime side of the Earth’s surface.

The Moon’s shadow moves across the Earth as it spins.

The Moon continues to move in its orbit too.

Total darkness of the eclipse only lasts a few minutes.

Some animals respond as if it were night.

f)        Distribute the work sheets. The model can be left in the classroom to help students complete the work sheets.

 This lesson is adapted from "Eye On the Sky - Lesson Plan"

Lunar and Solar Eclispe

DO YOU KNOW WHAT IS LUNAR AND SOLAR ECLISPE?

LUNAR ECLISPE

A lunar eclipse is an eclipse which occurs whenever the moon passes behind the earth such that the earth blocks the sun's rays from striking the moon. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, there is always a full moon the night of a lunar eclipse. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes.

The shadow of the Earth can be divided into two distinctive parts: the umbra and penumbra. Within the umbra, there is no direct solar radiation. However, as a result of the Sun's large angular size, solar illumination is only partially blocked in the outer portion of the Earth's shadow, which is given the name penumbra.

A penumbral eclipse occurs when the Moon passes through the Earth's penumbra. The penumbra causes a subtle darkening of the Moon's surface. A special type of penumbral eclipse is a total penumbral eclipse, during which the Moon lies exclusively within the Earth's penumbra. Total penumbral eclipses are rare, and when these occur, that portion of the Moon which is closest to the umbra can appear somewhat darker than the rest of the Moon.

A partial lunar eclipse occurs when only a portion of the Moon enters the umbra. When the Moon travels completely into the Earth¹s umbra, one observes a total lunar eclipse. The Moon's speed through the shadow is about one kilometer per second (2,300 mph), and totality may last up to nearly 107 minutes. Nevertheless, the total time between the Moon¹s first and last contact with the shadow is much longer, and could last up to 3.8 hours.

The relative distance of the Moon from the Earth at the time of an eclipse can affect the eclipse¹s duration. In particular, when the Moon is near its apogee, the farthest point from the Earth in its orbit, its orbital speed is the slowest. The diameter of the umbra does not decrease much with distance. Thus, a totally-eclipsed Moon occurring near apogee will lengthen the duration of totality.

SOLAR ECLISPE

A solar eclipse occurs when the Moon passes in front of the Sun and obscures it totally or partially. This configuration can only exist at New Moon, when Sun, Moon and Earth are on a single line with the Moon in the middle.

There are four types of solar eclipses:

• A partial solar eclipse occurs when the Sun is only partially overlapped by the Moon.
• A total solar eclipse occurs when the Moon completely obscures the Sun. This happens when the Moon is near perigee and its angular diameter as seen from Earth is identical to or slightly larger than that of the Sun. A total solar eclipse is the only opportunity to observe the Sun's corona without specialised equipment.
• An annular (ring-formed) eclipse occurs when the Moon's center passes in front of Sun's center while the Moon is near apogee. The Moon's angular diameter is then smaller than that of the Sun so that a ring of the Sun can still be seen around the Moon. This is similar to a penumbral eclipse.
• A hybrid eclipse occurs when the curvature of Earth's surface causes a single solar eclipse to be observed as annular from some locations but total from other locations. A total eclipse is seen from places on the Earth's surface that lie along the path of the eclipse and are physically closer to the Moon, and so intersect the Moon's umbra; other locations, further from the Moon, fall in the Moon's antumbra and the eclipse is annular.

The term "solar eclipse" is a misnomer: the phenomenon is actually an occultation. An "eclipse" occurs when one celestial object passes into the shadow cast by another (as with an eclipse of the Moon). An "occultation' occurs when one body passes in front of another. When at its new phase the Moon passes in front of, or occults, the Sun, as seen from Earth, the Moon also casts a small shadow on Earth. An "occultation" of the Sun is therefore also a partial "eclipse" of Earth.

Observing a solar eclipse

Looking at the Sun is dangerous at any time when any part of the brilliant visible disk of the Sun (its photosphere) is visible; to do so can cause permanent eye damage. This is true at any time, including during solar eclipses; since an eclipse offers an unusually high temptation to look at the Sun, there is a high incidence of eye damage caused during solar eclipses. Viewing the Sun through any kind of optical aid, binoculars, a telescope, or even a camera's viewfinder- is extremely dangerous.