ملخص Exam Review Summaries في العلوم باللغة الإنجليزية للصف السادس (2)

Science Grade 6

T3 Exam Review Summaries 2021

Chapter 10 , 11 and 12

Al Asayel School، Earth’s Motion

Earth moves through space in two ways. It revolves around the Sun and also rotates around its own axis

Revolution، Rotation، Earth’s axis

Revolution is the orbit of an object around

another object ()الدوران في مدار

Equator

• The Sun’s gravitational pull is very strong. The planets in our solar system all revolve around the Sun.
• It takes Earth 365.25 days or one year to complete a

revolution around the Sun.

Rotation is the spin of an object around

its axis ()دوران حول نفسه

• An axis is an imaginary line that cuts through the center of Earth. It runs from the North Pole to the South Pole.
• Earth takes 24 hours, one day, to complete a full rotation.

Day، Night

The average distance from Earth to the Sun is known as an astronomical unit (AU)

In early January, Earth is closest to the Sun.

In early July, Earth is farthest from the Sun

Earth’s rotation is the reason we have day and night.

Earth does not orbit around the Sun in a perfect circle, its path is elliptical. The distance between Earth and the Sun is not always the same

Earth’s Seasons

As Earth revolves around the Sun, different amounts of sunlight hit Earth’s surface. This is due to the axis tilt. Different amounts of sunlight result in different seasons

Earth’s axis is pointing away from the Sun. In this case, the Northern Hemisphere is receiving less direct sunlight and is experiencing winter. Daylight hours are shorter than darkness hours.

Earth’s axis is neither facing toward the Sun nor pointing away from it. The fall equinox is the second time in a year an equinox occurs

Earth’s axis is neither facing toward the Sun nor pointing away from it. Daylight hours and hours of darkness are equal.

Earth’s axis is pointing towards the Sun. In this case, the Northern Hemisphere is receiving more direct sunlight and is experiencing summer. Daylight hours are longer than darkness hours.

Spring Equinox، Summer solstice، Fall Equinox، Winter Solstice

The winter solstice: ● occurs around December 21

in the Northern Hemisphere ● is the shortest day of the

year ● happens when the North

Pole points away from the Sun

The summer solstice:

The fall equinox:

The winter solstice:

• occurs around June 21 in the ● occurs around September 21 ● occurs around December 21

Northern Hemisphere

in the Northern Hemisphere

• is the longest day of the year ● has equal amounts of
• is the shortest day of the
• happens when the North

daylight and darkness، year

Pole points toward the Sun ● happens when Earth’s axis ● happens when the North

does not point toward or

Pole points away from the

away from the Sun

Sun، Moon Phases

A moon phase is the shape of the lit portion of the Moon that is visible from the Earth

the Moon rotates on its own axis while revolving Earth.

The Moon's rotation and revolution are both 27.3 day

Waxing

the portion of the Moon that is lit becomes larger

The Moon waxes from right to left. It begins from a new moon Waxing moon phases:

• waxing crescent moon ● first quarter moon
• waxing gibbous moon

The Moon moves between eight different moon phases during the lunar month. A lunar month lasts 29.5 days. It is the amount of time it takes the Moon to display all eight of its phases.

During this time, the sunlit part of the Moon, as seen from Earth, either increases or decreases

the Moon does not make any light of its own. The light we see from the Moon is actually sunlight

that is reflected by the Moon’s surface

The Moon does not actually change its shape. Half of the Moon is always lit, but you don’t always see the full half from Earth

Waning

the portion of the Moon that is lit becomes smaller

The Moon wanes from left to right. It begins from a full moon Waning moon phases:

• waning gibbous moon ● last quarter moon
• waning crescent moon

During a waxing moon, the lit side is always on the

right

A full moon occurs when the

Earth is in between the Sun and the

Moon

These are the shapes of the Moon that are actually seen

from Earth

A new moon occurs when the Moon is between Earth and the Sun

During a waning moon, the lit side is always on the

left، Tides

Tides are the continuous rise and fall of water levels in oceans and seas.

The rise and fall of the water is

caused by the gravitational forces

of the Sun and Moon acting on the Earth as it rotates.

The location of tides changes daily as the Earth rotates.

The Moon affects tides on Earth about two times more than the

Sun

The Moon’s gravitational force causes water to bulge

toward it, creating high tides.

The tidal effect on the oceans is higher in areas closest to and farthest

away from the Moon

Spring tides

During the full moon or new moon phases, the Moon is in line with the Sun. The Sun’s gravitational pull is added to the Moon’s gravitational pull.

As a result of the strong gravitational pull, spring tides occur.

Spring tides are: ● high tides that are higher than usual ● low tides that are lower than usual

The difference between high and low tides is large.

Neap tides

During the first quarter moon or the last quarter moon, the Moon and the Sun’s gravitational pull are perpendicular (at 90°) to each other.

As a result of the weaker gravitational pull, neap tides occur.

Neap tides are: ● high tides that are lower than usual ● low tides that are higher than usual

The difference between high and low tides is small.

Eclipses

An eclipse occurs when an object in space blocks another object from its light source

Solar eclipse

When the Sun, Moon, and Earth are positioned in a straight line, the Moon blocks the Sun and causes a solar eclipse

Lunar eclipse

A lunar eclipse occurs when Earth is between the Moon and Sun. When this happens, Earth casts a shadow on the Moon.

Depending on the position of the shadow and the location on Earth, an eclipse can either be total or partial.

Total solar eclipse، Partial solar eclipse

• Sun, Moon and Earth line up perfectly ● Sun, Moon and Earth do not line up perfectly ● Moon appears to completely cover the Su●n Moon appears to only cover a part of the Sun

The Moon does not create its own light. It reflects the light from the Sun. A lunar eclipse blocks out the brightness of the full moon

Total lunar eclipse، Partial lunar eclipse