Earth, sun and moon: phases, eclipses and seasons

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टीचर्स के लिए: Earth, sun and moon: phases, eclipses and seasons (NGSS Middle School Science, Earth and Space Science) के लिए इस्तेमाल के लिए तैयार लेसन स्लाइड्स, रिवीज़न नोट्स — इन्हें अपने लेसन में इस्तेमाल करें, या टॉपिक को एक इंटरैक्टिव क्लास एक्टिविटी की तरह चलाएं जिसे आपके स्टूडेंट्स लाइव गेम की तरह खेलें।

लेसन नोट्स

Moon's Orbit and Rotation

The Moon orbits Earth once every 27.3 days.
The Moon rotates on its axis once every 27.3 days (same as its orbital period).
Because rotation and revolution are synchronized, we always see the same side of the Moon (nearside).
The Moon's orbit is elliptical, so its distance from Earth varies; average distance is about 385,000 km.
The Moon moves anti-clockwise around Earth when viewed from above the North Pole.
The Moon's diameter is just under one-third of Earth's diameter.

Phases of the Moon

The Moon does not make its own light — we see it because it reflects sunlight from the Sun.
The Moon is always half lit by the Sun. As the Moon orbits Earth, different portions of that lit half face Earth, which is why its shape appears to change.
The 8 phases, in order, are: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent.
At new moon, the lit side faces away from Earth. At full moon, the lit side faces directly toward Earth.
This cycle of phases repeats about every 28 days.

Phases of the Moon

Moon's Surface

The Moon's surface is covered with regolith (lunar soil), which lacks organic matter.
Dark areas on the Moon are called maria (seas), which are basaltic plains.
Bright areas are called highlands, which are higher in elevation.
The nearside has more maria than the farside.
The farside was first photographed by the Soviet spacecraft Luna 3 in 1959.

Solar Eclipses

A solar eclipse occurs when the Moon passes directly between the Sun and Earth, blocking the Sun's light.
Solar eclipses happen only when the Sun, Moon, and Earth are aligned in the ecliptic plane.
The Moon's shadow has two parts: the umbra (inner, fully dark) and the penumbra (outer, partially dark).
A total solar eclipse happens when the Moon completely covers the Sun, visible only from within the umbra.
A partial solar eclipse occurs when only part of the Sun is blocked, visible from the penumbra.
Solar eclipses are rare and brief because the Moon's shadow covers a small area and Earth rotates rapidly.
During totality, the Sun's corona and solar prominences become visible.

Solar eclipse geometry

Lunar Eclipses

A lunar eclipse occurs when the Earth passes between the Sun and the Moon, casting its shadow on the Moon.
Lunar eclipses happen only during a full moon when all three bodies are aligned in the ecliptic plane.
Earth's shadow also has an umbra and penumbra.
A total lunar eclipse occurs when the Moon passes completely into Earth's umbra.
A partial lunar eclipse occurs when only part of the Moon enters the umbra.
Lunar eclipses can last for hours and are visible from anywhere on Earth's night side.
Lunar eclipses do not occur monthly because the Moon's orbit is inclined about 5° to Earth's orbit.

Lunar eclipse geometry

Seasons: Cause and Effect

Seasons are caused by the 23.5-degree tilt of Earth's axis and its revolution around the Sun.
Earth's axis always points in the same direction, toward Polaris (the North Star).
When a hemisphere is tilted toward the Sun, it receives more direct sunlight and has longer days, causing summer.
When a hemisphere is tilted away from the Sun, it receives indirect sunlight and has shorter days, causing winter.
The distance from the Sun does not cause seasons; in fact, Earth is closest to the Sun during Northern Hemisphere winter.
Seasons are reversed in the Northern and Southern Hemispheres.

Earth's revolution around the Sun showing the seasons in the Northern and Southern Hemispheres.

Solstices and Equinoxes

The summer solstice (around June 21) is when the Sun's rays hit the Tropic of Cancer most directly; it's the longest day in the Northern Hemisphere.
The winter solstice (around December 21) is when the Sun's rays hit the Tropic of Capricorn most directly; it's the shortest day in the Northern Hemisphere.
At the equinoxes (around March 21 and September 22), the Sun shines directly on the equator, and day and night are nearly equal.
The vernal equinox occurs in spring, and the autumnal equinox occurs in fall.
Solstices and equinoxes mark the start of seasons in many calendars.

Earth's axial tilt relative to its orbital plane

Key Vocabulary

Orbit: The path an object takes around another object.
Rotation: The spinning of an object on its axis.
Revolution: The movement of one object around another.
Axis: An imaginary line through the center of an object around which it rotates.
Ecliptic: The plane of Earth's orbit around the Sun.
Umbra: The inner, darkest part of a shadow.
Penumbra: The outer, lighter part of a shadow.
Solstice: The time when the Sun reaches its highest or lowest point in the sky at noon.
Equinox: The time when the Sun crosses the celestial equator, making day and night equal.

स्लाइड्स

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प्रैक्टिस सवाल

फ्री प्रीव्यू — 45 में से 8 सवाल। सभी देखने के लिए साइन अप करें।

1.What is the time taken for the Moon to complete one orbit around the Earth?
Easy
- A24 hours
- B27.3 days
- C365.25 days
- D28 days
2.Which of the following is the correct order of the Sun, Earth, and Moon during a total solar eclipse?
Easy
- ASun, Moon, Earth
- BSun, Earth, Moon
- CMoon, Sun, Earth
- DEarth, Sun, Moon
3.The Moon has an atmosphere.
Easy
True or false?
4.Why do we always see the same side of the Moon from Earth?
Easy
- ABecause the Moon does not rotate on its axis.
- BBecause the Moon rotates on its axis at the same rate as it revolves around the Earth.
- CBecause the Moon revolves around the Earth in the opposite direction to its rotation.
- DBecause the Moon is tidally locked to the Sun.
5.What is the name of the outer part of the Moon's shadow during a solar eclipse?
Easy
- Aumbra
- Bpenumbra
- Ccorona
- Dmaria
6.During a lunar eclipse, the Earth is between the Sun and the Moon.
Easy
True or false?
7.Why is it hotter at the equator than at the poles?
Easy
- ABecause the equator is closer to the Sun.
- BBecause sunlight strikes the equator more directly.
- CBecause the equator has more volcanoes.
- DBecause the equator rotates faster.
8.Which of the following are true about the Moon? (select all that apply)
Medium
- AIt takes 27.3 days to orbit the Earth.
- BIt has a substantial atmosphere.
- CIt always shows the same face to Earth.
- DIts surface is covered with regolith.
- EIt is larger than the Earth.

और सवाल

9.Match each term with its correct description.
Easy
- Rotation
- Revolution
- Orbit
- Spinning on an axis
- Path around another object
- One trip around the Sun
10.Put the following events in the correct order for a total solar eclipse to occur.
Medium
- Moon passes directly in front of the Sun
- Earth, Moon, and Sun align in a straight line
- Moon's shadow falls on Earth
- Sun's corona becomes visible
11.During a lunar eclipse, the Moon can appear red because
Medium
- Athe Moon is covered by Earth's umbra and no light reaches it
- BEarth's atmosphere bends red light into the umbra, so some red light reaches the Moon
- Cthe Sun emits red light during an eclipse
- Dthe Moon's surface is made of red rock
12.Which of the following is the correct order of the Moon's phases?
Medium
- ANew moon, first quarter, full moon, third quarter
- BNew moon, full moon, first quarter, third quarter
- CFull moon, new moon, first quarter, third quarter
- DFirst quarter, new moon, full moon, third quarter
13.The Moon's diameter is approximately what fraction of the Earth's diameter?
Easy
- Aone third
- Bone half
- Cone quarter
- Done tenth
14.If the Moon's orbital period were shorter than its rotation period, what would an observer on Earth most likely see?
Medium
- ADifferent sides of the Moon over time
- BThe same side of the Moon always
- CNo Moon at all
- DThe Moon rotating faster than it orbits
15.The Moon's average distance from Earth is about 385,000 km. If Earth's radius is about 6,371 km, approximately how many Earth radii is the Moon from Earth?
Medium
- A60
- B6
- C600
- D23,481
16.Which of the following are necessary for a total solar eclipse to occur? (Select all that apply)
Medium
- AThe Moon is in the new moon phase
- BThe Sun, Moon, and Earth are aligned in a straight line
- CThe Moon is in the full moon phase
- DThe observer is in the Moon's umbra
- EThe observer is in the Moon's penumbra
17.The Moon's orbit is a perfect circle.
Easy
True or false?
18.The images below show five phases of the Moon as seen from Earth over about a month. Which statement best describes what causes the Moon to go through phases?
Medium
- ALight from Earth reflects off both the Sun and the Moon, creating a rotating pattern.
- BThe Moon produces a constant amount of its own light, and its rotation changes how much of that light reaches Earth.
- CEarth casts a shadow on the Moon, and the positions of the Sun, Earth, and Moon change relative to each other over time.
- DSunlight reflects off the Moon, and the changing positions of the Sun, Earth, and Moon relative to each other change how much of the lit half of the Moon we see.
19.Match each phase of the Moon with its description.
Medium
- New moon
- Full moon
- First quarter
- Moon is between Earth and Sun
- Earth is between Moon and Sun
- Moon is at a right angle to Earth-Sun line
20.Put the following events in the correct order for a lunar eclipse to occur.
Medium
- Full moon phase
- Earth between Sun and Moon
- Moon enters Earth's umbra
- Moon appears dark or red
21.A student wants to model how the tilt of Earth's axis causes the seasons. They use a globe tilted at 23.5° with the North Pole pointing toward a fixed star, and a lamp representing the Sun. As they move the globe around the lamp, they keep the North Pole pointing at the star. Which statement correctly describes what this model demonstrates?
Medium
- AThe distance from the Sun changes, causing the seasons.
- BThe tilt of Earth's axis causes different hemispheres to receive more direct sunlight at different times of the year.
- CThe Sun's energy output changes as Earth orbits, causing the seasons.
- DThe Earth's rotation speed changes, causing the seasons.
22.A student sets up an experiment to model how the angle of sunlight affects heating. They shine a desk lamp at a piece of black card from directly above (90°) and then at a 45° angle, keeping the lamp at the same distance. They measure the temperature rise over 5 minutes in each case. Which set of variables is correct for this experiment?
Hard
- AIndependent variable: temperature rise; dependent variable: angle of light; controlled variables: lamp, distance, card, time.
- BIndependent variable: angle of light; dependent variable: temperature rise; controlled variables: lamp, distance, card, time.
- CIndependent variable: angle of light; dependent variable: temperature rise; controlled variables: lamp, distance, card, but not time.
23.A student claims that a lunar eclipse occurs every month. Which of the following reasons explain why this is NOT true? (Select all that apply)
Hard
- AThe Moon's orbit is inclined about 5° to Earth's orbit.
- BThe Moon's shadow is too small to cover Earth.
- CThe Sun, Earth, and Moon are not always in the same plane.
- DThe Moon's orbital period is 27.3 days, not 30 days.
24.During a solar eclipse, the Moon's shadow has two parts: the umbra and the penumbra. The umbra is the outer part where light is only partially blocked.
Easy
True or false?
25.Match each part of an eclipse shadow with its correct description.
Medium
- Umbra
- Penumbra
- Ecliptic
- Inner, cone-shaped part where all light is blocked
- Outer part where light is only partially blocked
- The plane of Earth's orbit around the Sun
26.A student observes that during a total solar eclipse, the Moon almost exactly covers the Sun. They know the Sun is about 400 times farther away than the Moon, and its diameter is about 400 times larger. Which of the following best explains why the Moon can completely block the Sun?
Challenge
- AThe Sun's light is blocked by Earth's atmosphere.
- BThe Moon and Sun have the same angular size as seen from Earth.
- CThe Moon is larger than the Sun.
- DThe Sun is smaller than the Moon.
27.The Moon's surface has oceans and lakes.
Easy
True or false?
28.Which side of the Moon has more dark areas (maria)?
Easy
- AThe near side
- BThe far side
- CBoth sides equally
- DNeither side
29.What is the average distance from the Moon to the Earth?
Easy
- Aabout 385,000 km
- Babout 149,597,871 km
- Cabout 60,000 km
- Dabout 6,371 km
30.The Moon's rotation period is the same as its orbital period.
Easy
True or false?
31.A total solar eclipse can be seen from any location on Earth.
Easy
True or false?
32.What is the name given to the inner, cone-shaped part of a shadow during an eclipse?
Easy
33.Complete the sentences about the Moon's surface.
Easy
The dark areas on the Moon are called ____ and the bright areas are called ____.
34.How many days does it take the Moon to complete one orbit around the Earth?
Medium
35.What is the name of the plane in which Earth orbits the Sun?
Easy
36.The Earth's average distance from the Sun is 149,597,871 km. If the Earth's radius is about 6,371 km, how many Earth radii is the Earth from the Sun? Give your answer to the nearest thousand.
Medium
37.The Moon's average distance from Earth is about 385,000 km. If the Earth's radius is about 6,371 km, approximately how many Earth radii is the Moon from Earth? Give your answer to the nearest whole number.
Easy
38.Complete the sentences about the Earth and the Moon using the correct terms.
Easy
The Earth spins on its axis once every ____ hours. The Moon spins on its axis once every ____ days.
39.During a total solar eclipse, the Sun, Moon, and Earth are aligned in a straight line with the ___ in the middle. The inner, cone-shaped part of the Moon's shadow is called the ___, and the outer part is called the ___.
Easy
During a total solar eclipse, the Sun, Moon, and Earth are aligned in a straight line with the ____ in the middle. The inner, cone-shaped part of the Moon's shadow is called the ____, and the outer part is called the ____.
40.The Moon's diameter is roughly what fraction of the Earth's diameter? (Give your answer as a fraction in simplest form, e.g., 1/3)
Easy
41.In the Northern Hemisphere, the summer solstice occurs around June 21 when the North Pole is tilted ___ the Sun. The winter solstice occurs around December 21 when the North Pole is tilted ___ the Sun.
Medium
In the Northern Hemisphere, the summer solstice occurs around June 21 when the North Pole is tilted ____ the Sun. The winter solstice occurs around December 21 when the North Pole is tilted ____ the Sun.
42.What is the angle of tilt of the Earth's axis from the vertical?
Medium
43.A model shows Earth at two points in its orbit around the Sun: about 147 million km away at one point and about 152 million km away at the other (a difference of less than 3%). Which of the following best explains why a place on Earth still experiences a change of seasons as Earth travels around the Sun?
Medium
- AEarth's tilted axis causes uneven heating of Earth's surface by the Sun.
- BEarth's tilted axis makes the Sun appear larger in the sky.
- CEarth's changing distance from the Sun causes uneven heating of its surface.
- DEarth's changing orbital distance changes how far the Sun is from Earth.
44.A student claims that the seasons are caused by the changing distance between Earth and the Sun. Explain why this is incorrect, using evidence from the fact that when it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere.
Hard
45.The Earth's average distance from the Sun is 149,597,871 km. If the Earth's radius is about 6,371 km, how many Earth radii is the Earth from the Sun? Give your answer to the nearest thousand.
Medium
- A23481
- B25829
- C21133
- D28177

रिवीज़न नोट्स

## Earth, Sun, and Moon System ### Lunar Phases - The Moon's phases are caused by its orbit around Earth, changing the portion of the sunlit side we see. - **Major phases**: new moon (0% illuminated), first quarter (50%, right half lit in Northern Hemisphere), full moon (100%), last quarter (50%, left half lit). - **Intermediate phases**: waxing crescent (between new and first quarter), waxing gibbous (between first quarter and full), waning gibbous (between full and last quarter), waning crescent (between last quarter and new). - **Cycle**: A lunar month averages 29.5 days from one new moon to the next. - **Waxing** = illuminated area increases; **waning** = decreases. - **Memory aid**: "DOC" – in Northern Hemisphere, first quarter looks like a D, full like O, last quarter like C. ### Eclipses - **Solar eclipse**: Moon passes between Sun and Earth, blocking sunlight. Occurs at new moon. - **Lunar eclipse**: Earth passes between Sun and Moon, casting shadow on Moon. Occurs at full moon. - Eclipses don't happen every month because the Moon's orbit is tilted relative to Earth's orbit. ### Seasons - Caused by Earth's **23.5° axial tilt** relative to its orbital plane. - **Summer solstice**: Northern Hemisphere tilted toward Sun, longest day. - **Winter solstice**: Tilted away, shortest day. - **Equinoxes**: Tilt is sideways, equal day and night. - **Key**: Seasons are NOT due to distance from Sun (Earth is actually closest in January). ### Quick Facts - The Moon is tidally locked: same side always faces Earth. - A lunar day (sunrise to sunrise on Moon) equals one lunar month. - Earthshine: faint light on the dark part of a crescent Moon, caused by sunlight reflecting off Earth.

Lunar phase: The apparent shape of the Moon's sunlit portion as seen from Earth, changing over a lunar month.
New moon: Phase when the Moon is between Earth and Sun; the side facing Earth is dark (0% illuminated).
Full moon: Phase when Earth is between Moon and Sun; the entire near side is illuminated (100%).
Waxing: Describes phases when the illuminated area increases (from new to full).
Waning: Describes phases when the illuminated area decreases (from full to new).
Solar eclipse: Event when the Moon blocks the Sun's light from reaching Earth, occurring at new moon.
Lunar eclipse: Event when Earth's shadow falls on the Moon, occurring at full moon.
Axial tilt: The 23.5° tilt of Earth's axis, causing seasons as Earth orbits the Sun.
Equinox: Twice a year when day and night are equal length; marks the start of spring or autumn.
Solstice: Twice a year when the Sun reaches its highest or lowest point at noon; marks longest and shortest days.

फ्लैशकार्ड

What causes the phases of the Moon?

The phases of the Moon are caused by the changing relative positions of the Earth, Moon, and Sun, which affect how much of the Moon's sunlit side is visible from Earth.

How long does it take for the Moon to complete one cycle of phases?

One complete cycle of lunar phases, called a lunar month, averages about 29.5 days.

What are the four major lunar phases?

The four major lunar phases are new moon, first quarter, full moon, and last quarter (also called third quarter).

What are the four minor lunar phases?

The four minor phases are waxing crescent, waxing gibbous, waning gibbous, and waning crescent.

What does 'waxing' mean in terms of the Moon?

Waxing means the illuminated portion of the Moon is increasing, from new moon toward full moon.

What does 'waning' mean in terms of the Moon?

Waning means the illuminated portion of the Moon is decreasing, from full moon toward new moon.

During which phase is the Moon between Earth and the Sun?

During the new moon phase, the Moon is between Earth and the Sun, so the side facing Earth is not illuminated.

During which phase is Earth between the Sun and the Moon?

During the full moon phase, Earth is between the Sun and the Moon, so the entire sunlit side of the Moon faces Earth.

What is a solar eclipse?

A solar eclipse occurs when the Moon passes directly between the Sun and Earth, blocking the Sun's light from reaching part of Earth.

What is a lunar eclipse?

A lunar eclipse occurs when Earth passes directly between the Sun and the Moon, casting a shadow on the Moon.

Why don't we have a solar eclipse every new moon?

The Moon's orbit is tilted relative to Earth's orbit, so the Moon usually passes above or below the Sun from our perspective, not directly in front of it.

What causes Earth's seasons?

Seasons are caused by the 23.5° tilt of Earth's axis as it orbits the Sun, which changes the angle and duration of sunlight at different latitudes throughout the year.

When is the Northern Hemisphere tilted toward the Sun?

The Northern Hemisphere is tilted toward the Sun during summer (around June solstice), resulting in more direct sunlight and longer days.

What is the relationship between the Moon's rotation and its orbit?

The Moon is tidally locked to Earth, meaning it rotates once on its axis in the same time it takes to orbit Earth (about 27.3 days), so the same side always faces Earth.

What is a lunar month?

A lunar month is the time between successive recurrences of the same lunar phase, averaging about 29.5 days.

What is earthshine?

Earthshine is the dim illumination of the Moon's night side caused by sunlight reflecting off Earth's surface.

How does the Moon's appearance differ between the Northern and Southern Hemispheres?

The Moon's phase orientation is opposite: in the Northern Hemisphere, the right side is illuminated during waxing; in the Southern Hemisphere, the left side is illuminated.

What is a gibbous moon?

A gibbous moon is when the illuminated portion is more than half but not full, appearing bulging outward.

What is a crescent moon?

A crescent moon is when the illuminated portion is less than half, appearing as a thin sliver.

What is the difference between a new moon and an old moon?

A new moon is the beginning of the waxing cycle when the Moon is between Earth and Sun; an old moon is the last visible waning sliver before the new moon.

Why does the Moon appear to change shape?

The Moon appears to change shape because we see different amounts of its sunlit half as it orbits Earth.

What is the angle between the Sun and Moon during a first quarter moon?

During a first quarter moon, the Sun and Moon are at a 90° angle as seen from Earth, so half the Moon's visible side is illuminated.

What is the angle between the Sun and Moon during a full moon?

During a full moon, the Sun and Moon are opposite each other (180° apart) as seen from Earth.

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