Science 6th primary 2nd term unit 3 lesson 2

Lunar eclipse

It is the astronomical phenomenon which occurs when the sun, earth and the moon are nearly on one straight line with the earth in the middle hiding sunlight from the moon.

The phenomenon of lunar eclipse occurs in the middle of the lunar month (( full moon)) when the earth hides all the sunlight or a part of it from the moon on the rate of two lunar eclipses per year.

The lunar eclipse occurs in the middle of the lunar month (full moon)?

Because in the middle of lunar month the earth lies between sun and moon.

The lunar eclipse can be easily seen from the surface of earth !!

As it lasts for an hour or two!! in which the surface of moon gets colored with red and then returns to its original natural color.

Lunar eclipse can be seen easily from surface of the earth?

Because it lasts for an hour or two.

Note

· the only time in which lunar eclipse occurred three times was in 1982.

· Lunar eclipse doesn't require precautions. Because it doesn't harm eyes.

Activity >>> to show how does the lunar eclipse occur.

Tools:

Source of light ((sun)) , a coin ((earth)).

Steps:

1 – hold he coin between your thumb and fore finger as in figure.

2 – move the coin horizontally in front of the light source and observe with your eye the mount of light blocked by the coin.

Observation:

· the coin doesn't block light when it is away from the light path and as you move it, it starts to block light partially then totally.

· Then partially again until it finally becomes out of the light path again.

Conclusion:

1 – when the earth passes in front of the sun it forms two types of shadows which are cone shadows which are cone shadow (umbra) and semi-shadow (penumbra).

2 – the total lunar eclipse occurs when the whole moon enters the umbra region and partial lunar eclipse occurs when a part of the moon enters the umbra region.

Total lunar eclipse

It is the lunar eclipse which occurs when the whole moon

· in the total lunar eclipse, the sun , the earth and the moon all lie on a straight line with the earth in the middle.

** during the start of total lunar eclipse the color of the moon tends to be red.

The reason:

Although the sunlight is blocked from reaching the moon, there are some rays (red rays) are not absorbed by the earth's atmosphere these rd rays are refracted reaching reaching the moon to appear with red color.

Partial lunar eclipse

It is the lunar eclipse which occurs when a part of the moon enters the shadow area (umbra) of the earth.

Note

There is no annular lunar eclipse, because earth has a great size relative to that of the moon, so it always blocks all sunlight when it comes between the sun and the moon.

Semi-shaded lunar eclipse

It is the lunar eclipse which occurs when the moon enters the semi-shaded area only (penumbra) in which the moon light turns to be faint without being eclipsed.

Exercise >>> to calculate the time taken by lunar eclipse and its type?

Observe the figure which represents the lunar eclipse phases occurred on 21st February 2008.

** it started at 3 O'clock and it ended at 3.51 O'clock.

1 – Calculate the time taken for this lunar eclipse?

……………………………………………………………………………………………………………

………………………………………………………………………………………………………….

2 – Describe and determine the types of lunar eclipse illustrated in the figure?

Semi-shaded lunar eclipse >>> partial lunar eclipse >>>total lunar eclipse >>> partial lunar eclipse >>> semi-shaded lunar eclipse.

Solar eclipse

Lunar eclipse

Similarities

1 – each of them is an astronomical phenomenon caused by blocking of sunlight and casting the middle body shadow on the other celestial body.

So, they don't affect life on earth's surface.

2 – their types occur in regular periods of times and can be predicted.

3 – the shadow of both moon and earth is classified into umbra and penumbra.

Differences

Points

Solar eclipse

Lunar eclipse

1 -How does it occur?

Occur when the moon comes between earth and sun on one straight line.

Occurs when earth comes between moon and sun on one straight line.

2 – time of occurrence

Seen at morning only

Seen at night only

3 – its duration

Doesn't exceed seven minutes and few seconds.

Last for more than two hours.

4 – safety precautions

It requires precautions , warnings and special device to observe it, because it causes serious harms to the eye.

Doesn't require precautions, because it doesn't harm the eyes.

Enrichment information

** the moon returns back to the same point where the lunar or solar eclipses occurred after 18 years and 11 days.

This is what is called the Cerus of the Moon which was discovered by Babylonians in ancient ages.

Questions on lesson:

Complete the following statements:

1 - ………………………… is the phenomenon that occurs when the earth comes between sun and moon

2 – The lunar eclipse occurs in the ………………………… of the lunar month when the moon phase is …………………………………

3 – The lunar eclipse occurs with a rate of ………………….. per year.

4 – The only time in which lunar eclipse occurred three times was in ………………………..

5 – The lunar eclipse may last for ………………………….. or ………………………. Hours.

6 - ………………………. Is colored with red color during the lunar eclipse.

7 – The types of lunar eclipse are ……………………., ……………………………………. And ………………………………..

8 – In the total lunar eclipse, the sun earth and ………………………. Are on …………………….. with the earth in the middle.

9 – the moon appeared colord with red because of some …………............. rays, that are …………………………….. by the earth's atmosphere and reach the moon.

10 - ……………….. is the lunar eclipse which occurs when the moon enters the earth's penumbra.

11 – The time taken by the lunar eclipse occurred in February 2008 is …………………………..

12 – The lunar eclipse cycle strats with ……………………. Lunar eclipse then ………………………….

13 – The shadow of the moon and the earth is classified into …………………. And ……………………….

14 – The lunar eclipse doesn’t harm the eye, while solar eclipse causes …………………………

Choose the correct answer:

1 – the dark shadow of the earth is called ……………………….

a. antumbra b. penumbra c. umbra d. negative shadow.

2 – the lunar eclipse is formed when a celestial body comes between the sun and ……………

a. earth b. moon c. Jupiter d. mercury

3 – the lunar eclipse occurs ……………… times per year.

a. 1 b. 12 c. 5 d. 2

4 – we can observe the lunar eclipse when the moon phase is ………………………

a. crescent b. 1st quadrant c. full moon d. new moon.

5 – during the start of the total lunar eclipse the color of the moon tends to be ……………….

a. gray b. yellow c. orange d. red.

6 – all the following are from the types of lunar eclipse except ………………… eclipse.

a. total b. annular c. partial d. semi-shaded.

7 – the partial lunar eclipse occurs when a part of the moon enters the earth's ……………….

a. umbra b. penumbra c. antumbra d. atmosphere.

8 – when moon looks slightly faint, it indicates …………………….

a. total lunar eclipse b. partial lunar eclipse

c. semi-shaded lunar eclipse d. no eclipse.

9 – when the earth prevents all sunlight from reaching the moon it forms …………………..

a. total lunar eclipse b. partial lunar eclipse

c. penumbral lunar eclipse d. no eclipse.

10 – the duration of lunar eclipse is …………………… that of the solar eclipse.

a. longer than b. shorter than c. equal to d. twice.

Write the scientific term :

1 – the phenomenon that occurs two times per year in the middle of lunar month.

…………………………………………………………………………………………………………………………….

2 – the earth's shadow in which total lunar eclipse is formed.

……………………………………………………………………………………………………………………………

3 – the color of moon during the starting of total lunar eclipse.

…………………………………………………………………………………………………………………………..

4 –the lunar eclipse in which a part of the moon enters the earth's umbra.

…………………………………………………………………………………………………………………………..

Give reason for:

1 – the lunar eclipse occurs in the middle of the lunar month (full moon)?

………………………………………………………………………………………………………………………….

2 – the earth has an important role in lunar eclipse?

………………………………………………………………………………………………………………………..

3 – there is no annular lunar eclipse?

…………………………………………………………………………………………………………………………

4 – the two phenomena of lunar and solar eclipses are repeated regularly and can be predicted?

………………………………………………………………………………………………………………………..

Compare between solar and lunar eclipses :

Points

Solar eclipse

Lunar eclipse

1 -How does it occur?

2 – time of occurrence

3 – its duration

4 – safety precautions

Solar eclipse & lunar eclipse

3 – Semi-shaded (penumbral) lunar eclipse.

2 -partial lunar eclipse

1 – Total lunar eclipse

3 – Semi-shaded eclipse

2- Partial lunar eclipse

1- Total lunar eclipse

Type of lunar eclipse

Lunar eclipse phenomenon

The lunar eclipse

Ms. Marim 1