Spsd General Science 2010 - P5 The Solar System

The Earth takes 24 hours to make one complete rotation. This is known as a day and is the time it takes for the Earth to rotate once on its axis. This rotation is what causes day and night on Earth.

The Earth takes about 365 days to make one revolution around the Sun. This is known as a year. The concept of a year is based on the Earth's orbit around the Sun, which takes approximately 365.25 days. To account for this extra quarter of a day, we have leap years every four years, where an extra day is added to the calendar in February.

The Moon revolves around the Earth. This is because the Earth's gravitational pull keeps the Moon in orbit around it. The Moon takes approximately 27.3 days to complete one orbit around the Earth. This phenomenon is known as the Moon's revolution around the Earth.

The Earth rotates all the while without pausing although cannot feel it. The term "axis" is an imaginary line that goes through the centre of the Earth, from the North Pole (N) to the South Pole (S).

The changes in the Moon's appearance are known as its phases. The Moon goes through different phases as it orbits the Earth, which are caused by the changing positions of the Moon, Earth, and Sun. These phases include the new moon, crescent moon, first quarter moon, gibbous moon, and full moon. The phases of the Moon are a result of the varying amounts of sunlight that illuminate different parts of the Moon as seen from Earth.

Note!
Although Earth covers a large percentage of water, most of them are not for human consumption.

A satellite is an object in space that revolves around another object. The term "natural" satellite means that it is already there, nobody have changed it.

The correct answer is 28 days because this is the average length of the lunar month, which is the time it takes for the Moon to complete one orbit around the Earth. This duration is also known as the synodic month. During this time, the Moon goes through its different phases, such as new moon, first quarter, full moon, and third quarter, which are visible from Earth.

Always remember that the Earth takes 1 year (365 days) to make one complete revolution around the Sun.

in a decade = 10 years

The Sun and the Moon are not planets (Sun is a star, Moon is Earth's natural satellite) Therefore, there are only eight planets in the solar system namely, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Mathematics' calculation involved here.

The lines in between each planet are called orbits. Orbits are the paths that planets and other celestial objects follow as they revolve around a central body, such as a star. These paths are typically elliptical in shape and are determined by the gravitational pull between the objects. The concept of orbits is fundamental in understanding the motion and dynamics of objects in space.

The purpose of this huge device is to send information in the form of radio signals to a communication satellite in space.

Man-made satellites are important for various reasons. They are used for communication purposes, allowing people to connect and communicate with each other across long distances. They are also crucial for space exploration, as they enable scientists to gather data and explore outer space. Satellites are also used for observing the Earth, providing valuable information about weather patterns, climate change, and other environmental factors. Additionally, satellites play a vital role in weather forecasting, helping meteorologists predict and monitor weather conditions. Therefore, all the given options (i), (ii), (iii), and (iv) are correct explanations for why man-made satellites are important.

The correct answer is "a gigantic object that revolves around a star." This explanation aligns with the commonly accepted definition of a planet, which is a celestial body that orbits a star, is spherical in shape, and has cleared its orbit of other debris. The term "gigantic" implies that planets are significantly larger than other objects in their orbit, such as asteroids or moons. The term "revolves" indicates that planets move in an elliptical path around their star, rather than simply rotating on their axis.

The picture above shows a gibbous moon. A gibbous moon is when more than half, but less than fully, of the moon's illuminated surface is visible from Earth. In the picture, we can see that more than half of the moon is illuminated, indicating that it is a gibbous moon.

The term "closest star" in option D refers to the Sun.
The term "refracted" in option C means the phenomenon of bending of light ray. (you will learn in secondary 2)

The sun has a diameter of 1.4 million km! The sun is also about 1 200 000 times bigger than the Earth in volume!

Ans: rotation/spinning of the earth - not accepted