THE SOLAR SYSTEM
What is solar system?
The solar system: Is the arrangement of planets and other solid objects in the space in relation to the position of the sun. Normally planets are not arranged in a single line from the sun, they are scattered in the space. Normally the solar system sometimes is known as The universe.
IMPORTANCE OF SOLAR SYSTEM
1. It helps us to be familiar with the planet earth.
2. It helps to know the problems facing the earth.
3. It helps to acquire astronomical information.
5. It helps to know the components of the solar system.
6. It helps to know the behaviour, position and characteristics of the earth.
COMPONENTS OF THE SOLAR SYSTEM
A. THE SUN
Sun: is the biggest star of the hot gases which produce heat and light. The Sun it is one among the millions of stars that one sees at night except that it looks much bigger because it is closer to the earth than other distant stars. The sun is much larger than other distant stars from the earth, in fact the sun is much larger than all the planets put together. It's diameter is approximately 1.4 million kilometers and its mass is
approximately 330,000 times greater than that of the earth. The elements that form the material of the sun are also in different proportion from those of the earth. Normally the earth is relatively cold body but the sun is so hot that nearly all molecules are broken into their separate atoms and all are mixed together into a single hot gas. The average surface temperature of the sun is about 60000c. It is much hotter in the interior where it has temperature about 14,000,0000c. The sun is the main source of all light and heat that the planets receive.
Components of the Sun
The sun is composed of approximately;
i. 75% hydrogen.
ii. 23% helium.
iii. 3% of other elements.
Star: Is a heavenly body which possesses and transmit its own light. Galaxy: is the group of Million stars. Milky Way: Is the group of 100 billion stars. The scientific study of components of sola system is called Astronomy.
THE SOLAR ENERGY
Solar energy: is the energy produced from the sun. The sun is a major source of all energy in the earth. However the solar energy is in form of heat and light which is produced by the sun.
USES/IMPORTANCE OF SOLAR ENERGY
Solar energy is used in many ways such as:-
1. Used for drying purpose: This include clothes, grains, fruits and meat.
2. It support plants growth: when plants grow they use energy from the sun to manufacture their food through the process known as photosynthesis.
3. It provide electricity: Solar energy captured in solar panels and stored in batteries provides electricity used in generating industrial and home appliances like television, refrigerator, Oven, electric iron and cooker.
4. It provide vitamin D to human bodies.
5. It support the formation of rains through evaporation.
NB: Coal energy: is the solar energy stored in the bodies of plants grew thousands of years ago.
HOW THE USE OF SOLAR ENERGY PROMOTES ENVIRONMENTAL CONSERVATION
1. Solar energy support plant growh through process called photosythesis.
2. Solar energy it provide altenative source of energy e.g electricity. Hence reduce environmental pollution.
3. The use of solar energy at home reduce deforestation.
4. The use of solar energy also reduces the use of fuel like kerosene.
B. PLANETS
The planets: are bodies that revolve around the sun.
There are about 8 planets in the solar system which include:-
|
1. Mercury |
4. Mars |
7. Uranus |
|
2. Venus |
5. Jupiter |
8. Neptune. |
|
3. Earth |
6. Saturn |
|
As they revolve around the sun they appear to move around the star. All planets revolve around the sun anti-clockwise. That is why the Greeks called them planets means “Wandering stars”. All planets revolve around the sun in the same orbit that are elliptical and nearly the same planet.
The time taken to complete one revolution around the sun depends on the distance of the planet from the sun. All the light and heat of the planets come from the sun. Hence the temperatures on the planet depend on their relative distances from the sun.
Characteristics/ conditions/criteria for an objects to be planet
An object to be a planet, it needs to some requirements (criteria) defined by the International Astronomical Union (IAU) as follows:-
i. It needs to be in orbit around the sun.
ii. It needs to have enough power to pull itself in a spherical shape
iii. It needs to have "Cleared neighborhood of its orbit"
Note: Any object that doesn't meet this 3rd criteria is considered a dwarf planet. And so, Pluto is a dwarf planet is not a planet.
PLUTO IS NO LONGER A PLANET
However, Pluto is not a planet because:-
i. Pluto it has no power to push itself in a spherical form.
ii. It has no clearly orbit to support it in revolution.
iii. It has no any evidence to support it that whether pluto revolve around the sun or not.
PLANETS POSITION AND CHARACTERISTICS
|
Planet |
Approximat e distance from the sun |
No. Of moon
per planet |
Average temperatur e |
Period
per orbit |
|
Mercury |
58 million km |
0 |
340 0c |
88 days |
|
Venus |
108 million km |
0 |
40 0c |
225 days |
|
Earth |
152 million km |
1 |
15°c |
365.5 days |
|
Mars |
288 million km |
2 |
-100 0c |
1 year and 322 days |
|
Jupiter |
777 million km |
79 |
-138 0c |
11 years and 315 days |
|
Saturn |
1426 million km |
62 |
-247 0c |
21 years and 167 days |
|
Uranus |
2869 million km |
27 |
-200 0c |
84 years and 6 days |
|
Neptune |
4495 million km |
14 |
-265 0c |
164 years and 288 days |
CHARACTERISTICS OF EACH PLANET
1. MERCURY
i. Is the first hottest planet in the solar system.
ii. Is the planet with shortest orbit.
iii. It doesnot support life.
iv. It take about 88 days to complete one revolution around the sun.
v. Is the first planet in the position of solar system.
vi. Its distance from the sun is about 58 million kilomers.
vii. It has no satellite/moon
2. VENUS
i. Is the second hottest planet in the solar system.
ii. Is the second planet in the position of solar system.
iii. It does not support life.
iv. It take about 225 days to complete one revolution around the sun.
v. Its distance from the sun is about 108 million kilomers.
vi. It has no satellite/moon
3. THE EARTH
i. Is the third planet in the position of solar system.
ii. Is the only planet in the solar system which support life of living organisms.
iii. Is the fifth largest planet in the solar system.
iv. It has average temperature of about 15 degree centigrade.
v. It take about 365½ days to complete its revolution around the sun.
vi. Its distance from the sun is about 152 million kilomers.
vi. It has one satellite/moon.
4. MARS
i. Is the planet with two satellites or moons in the solar system.
ii. It does not support life.
iii. Is the fourth planet in the position of solar system.
iv. It take about one year 322 days to complete one revolution around the sun.
v. Its distance from the sun is about 288 million kilometers.
vi. It has two satellites.
5. JUPITER
i. Is the firts largest planet in the solar system.
ii. It the fifth planet in sthe position of solar system.
iii. It does not support life.
iv. It has about 79 stellites/moons.
v. Its distance from the sun is about 777 million kilometers.
vi. It take about 11 years and 315 days days to complete one revolution around the sun.
6. SATURN
i. Is the second largest planet in the solar system.
ii. It does not support life.
iii. It closed with snow ring.
iv. Is sixth planet in the position of solar system.
v. It take about 21 years and 167 days to complete one revolution around the sun.
vi. Its distance from the sun is about 1426 million kilometers.
vii. It has 62 moons/satellites.
7. URANUS
i. Is the fourth largest planet in the solar system.
ii. It take a distance of about 2869 million kilometers from the sun.
iii. It has 27 moons/satellites.
iv. Is the second coldest planet in the solar syste.
v. It take about 84 years and 6 days to complete one revolution.
8. NEPTUNE
i. Is the first coldest planet in the solar system.
ii. Is the planet in the solar system with longest orbit around the sun.
iii. It has a distance of about 4495 million kilometers from the sun.
iv. It take about 164 years and 288 days around the sun.
v. It has 14 moons/satellites.
C. COMETS
Comets: These are masses of ice, frozen gases, rock particles and dust which move around the sun. However comets revolve around the sun far beyond the limits of Neptune. They can be seen from the earth only when they come close to the sun. Comets they look like the star with bright tail.
D. ASTEROIDS
Asteroids: Are solid heavenly bodies in the solar syetem that revolve around the sun. They move between the orbits of Mars and Jupiter. The diameter of asteroids is less than 800km. These bodies cannot be seen without a telescope because they are very far away. Asteroids sometimes are called Planetoids because they look like panets. The large asteroids are called Ceres.
E. METEORS
Meteors: Are pieces of rocks falling from the outer space or atmosphere. They become visible between 110 and 145 km above the earth surface. They caused by friction with the atmosphere usually they become hot and disintegrates.
When they reach the earth surface they are known as Meteorites. Sometime meteorites when they reach the earth surface produce depression which later on can be filled with water to produce lake. Sometimes meteors reach the earth’s surface with such force, hence they make large holes or craters. An example of such craters in the world is the great meteor crater in Arizona desert in United states of America which is 150 meters deep and about 1 kilometer width.
METEORITES
Meteorites: Are disintegrated comets from the atmosphere. Are usually made up of nickel, iron or silica mineral elements. In Tanzania There are two sites with meteorites which are:-
i. Meteorites found at Ndolezi village, Mbozi district in Songwe region, about 65 km diatance from south west of Mbeya city.
ii. The meteorites found at Malampaka in Kwiba district, these meteorites fell in 1930.
NB: AXIS
Axis: Is a imaginary line where the body keep it revolution around another body. The Earth Axis: Is the imaginary line where by the earth revolve around the sun. ORBIT: Is a way in which the planet revolve around the sun.
The Eliptical orbit: Is the imaginary line where the planet revolve around the sun. Galaxy: Is the group of thousand stars.
Milkway: is the group of million stars.
F. SATELLITES
Satellites: are small bodies that revolve around the planets or any other body larger than itself. Sometimes are called moons of the planets. There are two types of satellites which are natural satellites and artificial satellites.
The moon is the largest natural satellite of the planet. Therefore there are about 185 natural satellites in the solar system. There are only six planets with satellites or moons these are Earth (1), Mars (2), Jupiter (79) Saturn (62), Uranus (27) and Neptune (14). Only two planets with no satellites which are Mercury and Venus. The artificial satellites are those man made satellites found in the atmosphere creted for wether forecasting, electronic data for map making, taking photographs and for communication.
THE EARTH
The Earth: is the third planet in the solar system and the only planet which support life of living organisms. However the earth is the fifty largest planet in the solar system.
CHARACTERISTICS OF THE EARTH
1. Is the third orderly and fifth largest planet in the solar system.
2. It is only planent in the solar system which support life because it is not more hoter or more cooler as well as it has varieties of water bodies.
3. It has the spherical shape, the earth is flattened at the poles but also it is wide at Equator.
4. About 75% of the earth is covered by water and only only 25% covered by landmass.
5. The large part of the southern hemisphere is covered by water masses like ice and ocean while the large part of northern hemisphere is covered by Landmasses.
THE SHAPE OF THE EARTH
About ¾ of the earth’s surface is covered by water. The shape of the earth is a flattened sphere called a Globe. The earth is flattened all the poles and it is wide at the equator indicated by measurements in diameters through poles. It has diameter of about 12,713 km between North and South pole while at the equator it has a diameter of about 12,757 km from west to east.
EVIDENCES WHICH PROVE THE SHAPE OF THE EARTH
There are some several evidences which are used to prove that the earth is sphere like structure, some of them are shown in the following: -
1. The sunrise and sunset: Normally there is different in sunrise and sunset in defferent places and time on the earth surface. However people in the east see the sun earlier than the people in the west due to earth’s rotation from west to east. If the earth was flat the whole world would have sunrise and sunset at the same time.
2. Circumnavigation of the Earth: If a someone traveling from a certain point of the earth and she/he go straight around the earth you will come to the point of origin. The first traveler around the world named Magellan in 1519-1522 proved this, image did not encounter abrupt edge over the world in his voyage.
3. Vertical aerial photographs: Photographs taken by satellites or aeroplane from the atmosphere show that the earth has a curved or round shape.
4. Ships visibility: When two ships come in to the coast at very far the front ship will be seen first before the anither. If the earth were flat the ship would have been seen all at once
5. The lunar eclipse: During the eclipse of the moon the earth shadow appear in a round shape. Only a spherical object can give a circular shadow.
6. The spherical horizon: when someone trying to observe the sky at the very high point it will give the sherical horizon.
7. Surveying with ranging poles: when the measurement taking on the earth surface by ranging pole wth the same height will differ in size the way distance increasing. Therefore if the earth is flat all ranging pole will remain the same throughout the earth surface.
PHYSICAL COMPONENTS OF THE EARTH
The Earth is made up of the : -
i. Atmosphere (air)
ii. Hydrosphere (water bodies)
iii. The crust solid
iv. Molten material
v. Biosphere (living things).
NB: The earth is the only planet in the solar system believed to have ability to support life because:-
i. The earth is not more hoter and more colder.
ii. Is the only planet on the solar system with water bodies.
THE MOON
The moon: is a natural satellite of the earth. Normally the moon is the largest natural satellite in the solar system. The moon has a solid spherical body with a diameter of 3456 kilometers. The distance from the earth to the moon is bout 384,403 kilometers. The moon takes 29 ½ days to make a complete revolution around the earth. The moon appears to rise in the east and set in the west because the earth spins from west to east. Among all planets only the earth sustains life due to its position from the sun. It is not very close or very far from the sun. Other bodies such as Neptune which is very far a way from the sun does not sustain life because it is very cold. Likewise Mercury which is very close to the sun does not sustain life because it is very hot.
THE EARTH MOVEMENT
Earth movement: is the movement of the earth on its axis or around the sun. Normally the earth is in motion all the time. No one can feel this motion because one moves with it, like all other planets.
TYPES OF EARTH MOVEMENT
The earth has two motions known as: -
i. Rotation
ii. Revolution
1. THE EARTH ROTATION
Rotation: is the spining of a body on its axis.
Earth’s rotation: is a spinning of the earth on its axis.
The earth Axis: is an imaginary line joining the north and south poles through the center of the earth. The earth’s axis makes an angle of 660 from the perpendicular. The earth rotates on its Axis from west to east. It makes one complete rotation after every twenty four (24) hours or one day.
EVIDENCES WHICH PROVE THAT THE EARTH ROTATE FROM WEST TO EAST
1. Travelling with fast moving bodies: When traveling in a fast moving vehicle we notice trees and other objects on both sides of the road moving in the opposite direction. This observation prove that, the earth rotates its axis from west to east.
2. sun rise and sun set: In the morning the sun appears to rise from east then in the evening the sun set to the west. Therefore this shows that the earth is moving from west to east.
3. Movement of stars: At night most stars appear to move across the sky from east to west. This indicates that the earth is moving from west to east.
EFFECTS OF THE EARTH ROTATION
1. Occurance of day and night: When the earth rotates its ixis it responsible for ocurance of day and night.The side that faces the sun will be expecting day light while the side that is not facing the sun at that time will be darkness (night). Therefore as the earth rotates its parts come alternatively in the light pass out of it again.
2. Difference in time between longitudes: The earth rotation cause the variation in time between places located at different longitudes. The different in time is usually determine by longitudinal differences between two or more places.
3. Gain or loss of day when crossing international date line: There is a tendency of losing or gaining day when one crossing international date line. However when traveling from the west to east across the international date line the one will gain the day or time, likewise, when one moves from east to the west across the international date line a one will lose the day or time.
4. Deflection of winds and ocean currents: The earth rotation cause the deflection of planetary winds and ocean currents. Normally the planetary winds and ocean currents are deflected clockwise (right side) to the northern hemisphere and anti clockwise (left side) to the southern hemisphere.
5. Occurance ocean tides: The ocean tides, is the periodic rising and falling of water level in the ocean. This process is caused by gravitational attraction caused by the sun and the moon. When the sun, moon and the earth are at straight line cause the tide rise, and when the sun, moon and the earth are not at straight line cause the tide falls. However tides are experienced at different places and times on the earth surface.
2. THE EARTH REVOLUTION
Revolution: Is the movement of one body around another.
The earth revolution: Is the movement of the earth around the sun. The earth takes 365
¼ days for a complete revolution. When the earth takes 366 days to accomplish one revolution is called a Leap year. Due to the shape of the earth’s orbit, the earth is very closer to the sun at one point of the year than at another. Therefore the speed of revolution is about 29.66 km per second.
THE EFFECTS OF THE EARTH REVOLUTION
When the earth revolves around the sun it cause the occurance of the following phenomenas: -
1. Changing in seasons of the year: Normally the earth revolution resulted in to changing in season of the year which are usually separated by temperature characteristics. However the seasons include summer, spring, winter and Autumn the are categorized in two hemispheres which include Norhern hemisphere and southern hemisphere.
2. Occurance of eclipses: The earth revolution resulted in to occurance of the solar and lunar Eclipse. The solar eclipse means the eclipse of the sun while the lunar eclipse means the eclipse of the moon.
3. Difference in the length of day and night: The earth revolution cause variation in length vof the day and night between longitudes and season. Some place at different time experience longer day and short nights while other places experience longer night and thirty days.
4. Changes in the latitude of the overhead sun: Normally the overhead sun appear to move northward in the Tropic of cancer 23.5°N and southward in the Tropic of Capricorn 23.5°S. Normally these places experience the overhead sun at different time of the year. However places beyond these latitudes never seen the overhead sun (the sun vertically).
5. Occurance of aphelion and perihelion: Normally due to the shape of the earth Axis when the earth revolve around its elliptical orbit cause some position to be much closer to the sun while one position to be far from the sun.
Aphelion is the furthest position of the earth from the sun it occurs on 4th July when the earth is at distance of about 152 million kilometers from the sun. Perihelion: Is the nearest position of the earth from the sun. It occurs on 3rd January when the earthbis at distance of about 147 million kilometers from the sun.
APHELION AND PERIHELION
Aphelion: is the furthest position of the earth from the sun. The earth is at Aphelion each year on 4th July when it is in 152 million kilometers from the sun.
Perihelion: is the nearest position of the earth from the sun. Normally the earth is at perihelion each year on 3rd January.
IMPORTANCE OF THE EARTH REVOLUTION
1. It helps to understand different eclipses which are taking place.
2. It helps to set calendars.
3. It helps to get different weather conditions in the year.
4. It helps people to adjust different activities by considering weather conditions.
5. It helps to prove about the earth movement.
6. It helps to identify different seasons of the year.
SEASONS
Season is the one of the four distinctive periods of the year separated from each other by different temperature conditions.
Seasons of the year in the Northern hemisphere.
1. Summer: the summer months are May, June and July.
2. Autumn: the Autumn months are August, September and October.
3. Winter: the Winter Months are November, December and January.
4. Spring: the spring months are February, March and April.
Seasons of the the Southern hemisphere
1. summer: the summer months are November, December and January.
2. Autumn: the Autumn months are February, March and April.
3. Winter: the winter months are May, June and July.
4. Spring: spring months are August , September and October.
CAUSE OF SEASONS
Seasons are caused by inclination of the earth’s axis and the earth’s revolution around the sun. The earth’s axis is tilted at an angle of 660 to the earth’s orbital plane and it is always pointing to the same direction in space. In its revolution around the sun one of the hemispheres is inclined towards the sun to one period of the year and away from it at another period of the year.
ECLIPSE
Eclipse: This is the movement of one heavily body between the two others, such that it casts shadow over the other. An eclipse is said to be total eclipse when the whole body is obscured i.e completely blocked from the sun light and it is described as a partial eclipse when the only part of the body becomes obscured. At any place an eclipse will last short time, hardly seven minutes because both the earth and the moon are in motion.
TYPES OF ECLIPSE
There are two types of eclipse which are:-
i. The Lunar eclipse
ii. The slar eclipse
1. THE LUNAR ECLIPSE (ECLIPSE OF THE MOON)
The lunar eclipse: Is the eclipse of the moon. It occurs when the earth passes between the sun and the moon, this casting its shadow over the moon.
1. THE SOLAR ECLIPSE
The solar eclipse: Is the eclipse of the sun.
This occurs when the moon passes between the earth and the sun casting its shadow over the earth.
THE SOLAR ECLIPSE
Umbra or total/eclipse is when the whole body is obscured i.e completely blocked from the sun’s light.
Penumbra/ partial eclipse is when only part of the body becomes obscured. THE APPARENT MOVEMENT OF THE OVERHEAD SUN
The overhead sun: Is the phenomena where by the sun appear at the right angle at different position of the earth. The apparent movement of the overhead sun is related to the different positions of the earth on its movement as it revolves around the sun.
-The overhead sun appears to move north wards and south wards in an osculating (swinging) manner. However the overhead sun’s northward limit is latitude 23.50N While in Southern hemisphere the overheadsun limit is 23.5°S. People beyond these latitudes never see the sun vertically above their heads.
The latitudes of 23.5 0N is known as Tropic of cancer While 23.50S is known as the Tropic of Capricorn.
SOLSTICE
Solstice: Is a phenomena that occurs when the earth poles are mostly inclined towards
or away from the sun. However this phenomena cause the earth pole which is inclined to the sun to receive maximum sunlight. Normally the summer solstice in the Northern hemisphere it occurs on 21 June in the Tropical of Cancer. While The winter solstice in Northern hemisphere occurs on 22 December when the sun is vertically overhead on the Tropical of Cancer in the Northern hemisphere.
WINTER SOLSTICE
THE EQUINOX
Equinox: Simply refers to equal length of day and night. However this is the period
where by the sun is ovehead at the equator twicely per year. The sun is overhead twice per year at the equator on 21st March and 23rd September. Normally the equinox of 21st March is known as the Spring equinox while the iquinox of 23rd September is known as the autumn equinox in the Nothern Hemisphere. However at equinox the length of day and night is equal over all places on the earth’s surface around the equator. Viewed from the Southern Hemisphere the solstices and the equinoxes are reversed.
LATITUDE AND LONGITUDE /PARALLEL AND MERIDIAN
Latitude: Is the angular distance north or south of the equator measured in degrees, minutes and seconds.
Parallels: are more commonly known as Latitudes Latitude/Parallel
These are angular distances which measured in degree minutes and seconds north or south of the equator.
The equator is latitude of 0°. The equator divides the earth into two equal parts (Hemisphere). The hemisphere north of the equator is northern hemisphere. The hemisphere south of the equator is known as Southern hemisphere. Latitude are also known as a parallel lines of equator because they never meet.The lines of latitude are measured from 00 (the equator) to 900 north and south.
CHARACTERISTICS OF LATITUDE
1. They measured in degree minutes and seconds.
2. They run from west to east across the prime meridian.
3. They used to locate the position of the place on the map.
4. They are used to locate the climate of the place.
5. They are used to calculate the local and international time
6. Are the lines drawn on a map from east to west.
LINES OF LATITUDE
1. The equator 00
2. The tropic of cancer 23 ½0N
3. The Tropic of Capricorn 23 ½0S
4. Arctic cycle 66 ½0N
5. Antarctic cycle 66 ½0S
PARALLEL OR LATITUDE 300N
Meridians: Are commonly known as Longitude.
Longitude/Meridian: Is the angular distance which measured in degrees, minutes and seconds between west and east of Greenwich meridian. They run from north to south. They are measured between West and East of Greenwich meridian.
Greenwich: is a longitude 00 . It is also known as prime meridian.
The prime meridian: is the line running through the poles (North and South) and is known as greenwich 00. Longitudes are measured from 00 to 1800 East or West of greenwich, all meridians are passing through the North and south poles.
CHARACTERISTICS OF LONGITUDE
1. They are measured in degree minutea and seconds.
2. They run from north to south of the equator.
3. They used to locate the position of the place on the map.
4. They are used to determine the climate of the place.
5. Are vertical lines runing from north to south.
Similarities between latitude and longitudes
1. Both they are measured in degree minutes and seconds.
2. Both they are used to locate the position of the place.
3. Both they divide the earth in two poles.
4. Both they are used to calculate the local and international time.
5. Both they are used to dertermine the type of climate on the earth surface.
THE IMPORTANCE OF PARALLEL AND MERIDIANS
1. Longitudes enable us to calculate local and International times of different places.
2. Latitudes help us to understand the variation in climate on the earth surface.
3. They are used by pilots and sailors to reach the direction.
4. They enable us to locate places on the maps. for example Tanzania is found at Latitude 6°00′S of the equator and Longitude 35°00′ E of Greenwich meridian.
THE GREAT CIRCLE
Great circles: Are the circles drawn on a globe or othe sphere which divide the earth in to two equal halves.
NB: All longitudes are great circles.
–Equator is only great circle
IMPORTANCE OF GREAT CIRCLE
1. The great circles are used to find the location of the place.
THE INTERNATIONAL DATE LINE
international date line (IDL): is a imaginary iline where date is changed or where the calendar day begins. The international date line was established in 1884. This it follow the meridian of 180° longitudes except when it crosses the land surface. It is located halfway round the world from the prime meridian (0°) established in Greenwich, England in 1852. Normally the international date line is in zigzag form, so as to avoid countries found on different longitudes to have the same time and day.
Principles
i. When one moves Eastwards and cross the international date line, one will gain a day.
ii. When one moves Westwards and a cross the international date line, one will lose a day.
CALCULATION OF LOCAL TIME AND INTERNATIONAL TIME
TIME
Time: Is a duration measured by second, minutes, hours, days, weeks, months years and so on. Normally time is a period used for a event or activity. It is measured in seconds, minutes, hours, days, months, years and so on.
TIME ZONES
Time zone: Is the region having the same standard time.
Normally standard time is common on time for all countries belonging to the same time zone for example, Tanzania, Kenya, Uganda, Ethiopia, Djibouti and Somalia use the same standard time. This is commonly referred to a the East African Standard time.
Normally internationally agreed to split the world in to 24 time zone according to Longitudes. The longitudinal division across the earth with an approximates with of 15° of longitude which is regular across the oceans.
NB: Large countries like Canada, USA and Russia have different standard times for different regions within them because they are crossed by many time zone.The earth rotates on its own axis from west to east once every twenty four hours (one day). This means that the earth turns through 3600 in twenty four hours.
All places along a given meridian will experience midday along the same meridian, it is known as Local Mean, on the Greenwich meridian is known as Local Mean Time (LMT).
When it is 12:00 noon, on the greenwh meridian it will be 1:00 pm at a place of 150E or 11:00 at a place of 150W.
Example1: Find the local time of Musoma in Tanzania (340E) when it is 12:00 in Kinshasa Zaire (150 300E).
Solution
i. Find the difference in degree of longitude between Kinshasa and Zaire 340 - 15030 = 18 ½
ii. Change degree in to hours
Solution
1° = 4 minutes 18 ½ = x
x= 4 X 18 ½ = 1 hour and 14 minutes.
1
iii. Find different in time between Kishasa and Musoma Solution
12:00 +1:14 = 13:14 pm Or 1:14 pm.
Therefore time for Musoma will be 13:14 pm
Since Musoma is to the east of Kinshasa, Musoma time will be ahead of that of Kinshasa by 1 hour and 14 minutes.
Example2:
If it is 9:30 am at kasse 330 150E what time is in Zanzibar 450 150E?
Steps
i. Find differences in degrees
450 .150
-330 . 150
12 . 00
ii. Change degree in to hours Solution
1°=4mins 12°=?
12°×4mins=1° 48mins
iii. Find differences in hrs 9:30- 48mins = 08:42
Therefore because Kase is ahead of Zanzibar, then the Zanzibar time will be behind of Kase, hence the time of Zanzibar will be 08:42 A.M
Example 3:
Find the local time for the youncle (30°W) if it is noon London (0°W) Steps
i. Find different in longitudes between Youncle and London Solution
30° – 0° = 30°
ii. Change degree in to hrs Solution
15 = 300 x 1hr = 2hr
15 15
iii. Find different in time between Youcle and London Solution
12.00
– 2.00
10.00
Therefore the time of youcle is = 10.00 a.m
Example4:
When it is 3.30pm at Nairobi (250E) what is the time for Comoro 1200E? Steps
i. Find different in longitudes between Nairobi and Comoro Solution
120°E-25°E=95°
ii. Change longitudes/degree in to hours Solution
1hr x950 = 950 = 6 1/3x 60
15 15
= 6hrs and 20 minutes
iii. Find different in time Solution
3:30 + 6:20=9:50 p.m
Therefore, the time of Comoro is 9:50 P.M CALCULATION OF LONGITUDES
Normally under this context are calculated by the consideration of time. Example1:
Find the longitude of Tanzania whose the local mean time is 2:00 pm when the longitude of Congo is 30° W (01:00 p.m).
Steps
i. Find different in time.
Sln
2:00pm-01:00 p.m=1hr.
ii. Change time in to longitude/degree sln
1hr=15°
1hr=? 1hr×15°/1hr=1hr/1hr 15°
iii. Find different in degree between Congo and Tanzania Solution
30°+15°=45°
Thus, because the time of Tanzania is ahead of Congo, the longitude position of Tanzania will be 45°E.
Example2:
Find the longitude position of Mogadishu whose the local time is 4:40pm. When the local time of Tunis is 10°E 2:20pm.
Steps/procedures
i. Find different in time between Mogadishu and Tunis.
Sln
4:40-2:20=2:20hrs
ii. Change hours in to minutes.
Sln
1hr=60min 2hrs=?
2hrs×60=1hr/1hr 120+20=140min.
iii. Change min in to degree Sln
If 4min=1° 140mins=?
140min×1°/4min=4min/4min 140÷4=35°E
iv. Find different in degree between Mogadishu and Tunis.
Sln
10°E+35°=45°E.
Therefore the time is Tunis is behind of Mogadishu, then Mogadishu must be located east of Tunis. Thus the latitude position of Mogadishu us 45°E.
GUIDING QUESTIONS
Qn: By means of well illustrated diagrams prove the sphericity of the planet earth.
QN: Prove the statement that the shape of the planet earth is manifested itself.
QN: Why Pluto is no longer a planet?
QN: Why Pluto is said to be a dwarf planet? Give three reasons.
Qn: Ouline any five (5) characteristics of the planet earth.
