FINDING POINTS ON A GLOBE

In order to both study and navigate the Earth, it is important to have a system for describing locations accurately and mathematically. This system must be generally accepted by everyone, and it must be easy to use and understand.

The simplest method for describing locations either on a planet, or on any flat object, is to create a grid. A grid is a series of evenly spaced imaginary lines that intersect with one another at right angles. One set of lines are distributed across the globe horizontally, and one set of lines are distributed vertically.

But wait a moment. How do we know where the top and bottom of the Earth are? Think about it. If the Earth is round, what point is the top? Let's consider a white marble. Where is the top of the marble? No matter which way you turn it, every side of the marble looks the same. But what happens when you spin the marble? As the marble spins, or rotates, for a few moments, there is a clearly defined top that remains pointing upwards.

Because the Earth is rotating around an imaginary axis, we can define a top and bottom. We call these the poles. Having a top and bottom of the Earth allows us to then draw the imaginary lines that we need for our grid. The lines that extend from pole to pole are called longitude, while the lines that circle the globe horizontally are referred to as latitude.

 

Latitude

Latitude is the angular distance of any object from the equator measured in degrees. The angular distance from the equator to itself is 0, thus the latitude at the equator is 0 °. If we move either up or down from the equator, our distance increases, and so does our angle to it. Eventually we reach either the North or South Pole. Standing on the these poles, places us at exactly a 90 ° angle to the equator.

At any location on Earth we can draw a circle around it, representing every point that is at the same latitude. If we were to cut the earth in half at the equator and place a large piece of paper in between the two halves, we would find that both halves were exactly the same size. As we move either up or down the Earth, cutting the planet into two pieces produces one large piece and one small piece. As we approach the poles, the large piece gets very big, while the small piece becomes much smaller. Drawing these imaginary lines at different latitudes produces what we call parallels. Although technically it is possible to draw an infinite number of parallels at any number of latitudes, there are a few which are important for you to understand as you study our planet.

The first of these is called the equator. The equator is located at 0 ° latitude. Going north from the equator we find the Tropic of Cancer. This parallel is located at 23.5 ° north. Continuing further northward we reach the Arctic Circle at 66.5 ° north. Continuing all the way to the top of the Earth at 90 ° latitude we encounter the North Pole. If we journey southward from the equator we will find the Tropic of Capricorn at 23.5 ° south. Continuing south we reach the Antarctic Circle at 66.5 ° south. Finally, at 90 ° south, we find the South Pole.

Longitude

As we have already read, the lines extending around the Earth horizontally are called lines of latitude. They measure how far north or south an object is on the Earth. The lines running vertically around the Earth are called longitude. These lines are called meridians, and measure how far east or west an object is.

As with latitude, longitude is measured as an angular distance. With latitude, the angular distance is measured from the equator. This is a natural place to begin. However, with longitude there is no natural beginning point. One of these lines must be designated as a prime meridian, or as the 0 ° mark, but which one? For many years, each country had its own prime meridian. France used a meridian passing through Paris, while England used a meridian passing through Greenwich, England. Either one worked just as well, as long as you were only communicating with people from the same country. But what happens as technologies improve, and travelers begin interacting with people from many different lands? If each country is using a different prime meridian to mark 0 ° longitude, then it would be impossible to give someone from another country a location, and have them be able to accurately find it.

Over time, more and more travelers began to recognize the meridian passing through Greenwich, England, as the Prime Meridian. In 1884, a group of scientists, navigators, and businessmen made Greenwich, England, the official worldwide Prime Meridian.

The further away from the Prime Meridian that one travels the higher their longitude becomes, until they reach 180 ° longitude. If an individual is in the Eastern Hemisphere, their longitude is measured in degrees east. If they are in the Western Hemisphere, their longitude is measured in degrees west.

Plotting Your Location

Using longitude and latitude, it is now possible to accurately describe any location on the Earth within a correct distance of only a few inches. Your home or school probably has a street address. Perhaps it looks something like 6088 Garden Gate Drive. These numbers tell the mailman where to deliver your mail, and visitors how to find you. While physical addresses are very useful, longitude and latitude are more concise and accurate. A physical address is based on a local system, understood and accepted only by a small community. Longitude and latitude are accepted worldwide by the entirety of humanity. If you know your longitude and latitude, you can tell a distant pen pal exactly where you are on this sphere-shaped planet.

For hundreds of years, calculating your longitude and latitude was a somewhat difficult process. Using specialized tools and the stars as a guide, trained experts could determine their location, and make sure that their travels were still on course. However, due to the limits of their equipment, these measurements were only approximate.

Today, anyone can quickly and accurately measure their location on the Earth. One popular method for determining the latitude and longitude of an object is through the use of Global Positioning Satellites, or GPS. Inexpensive GPS devices use the signals from satellites orbiting the Earth to calculate the exact location of the person holding the device. Many of these devices also allow the user to save their favorite locations in a small computer so that these locations can quickly be found in the future.

A song: Globe

"Globe" lyrics

The Earth is a tiny ball in space.
It's the only place that we know has a human race.
The Earth is a tiny ball in space; it's the only place...
Wow, the planet Earth is beautiful from outer space. It looks just like a globe! A globe is a small copy of the planet Earth. Do you know the main parts?
There is land on the surface of the globe
Seven sections of land on the globe
What are they called?
Those are the CONTINENTS.
North America, South America, Europe, Asia, Africa, Australia, Antarctica.
There is a lot of water on the globe
Covering three fourths of the globe
What is it called?
It's the OCEAN.
The ocean is divided into the Atlantic, Pacific, Indian, Arctic and Southern oceans.
There is a top point on the globe
There is a bottom point on the globe
What are they called?
The NORTH and SOUTH POLES
The North Pole is in the Arctic Ocean and the South Pole is on Antarctica.
What is the line that circles the globe;
An imaginary line that divides the globe?
What is it called?
It's called the EQUATOR.
The equator lies halfway between the North and South Poles.
Another line that circles the globe?
It divides the east and west parts of the globe.
What is it called?
That's the PRIME MERIDIAN.
The Prime Meridian is perpendicular to the Equator and crosses through the North and South Poles.
If you divide the globe in two parts.
And can only see half of the globe,
What is it called?
It's called a HEMISPHERE.
"Hemi" is Greek for "half" and a sphere is any round object... like a planet. Therefore, "half planet."
The Earth is a tiny ball in space.
It's the only place that we know has a human race.
It's the only place...

Video: maps

VIDEO ABOUT GEARS

LEARN ABOUT GEARS

Types of Simple Machines 
When you think of a machine, you probably think of something big like a washing machine or car or bulldozer. Those big machines are made up of smaller parts called simple machines. Simple machines are made of one or two parts, and they help us do work like making things move. There are several different kinds of simple machines:
- Inclined planes are like ramps that help you move something upward without lifting it. You can push it up the inclined plane instead.
- Levers make it easier to lift a load. (A teeter-totter or see-saw is a lever. Is it easier to lift a friend up in your arms, or by riding the teeter-totter?)
- Wheels help you move something across the ground.
- Pulleys allow you to pull down on a rope to lift a heavy load. (It's easier to pull down than up, because you can use gravity and your weight to help.)
- Screws are simple machines that move in a straight line (into a piece of wood, for example) when you turn them. It works a lot easier than just trying to push something into the wood!
-  A wedge is used to help split things in two. An axe used for chopping firewood is a wedge.

 Gears Are Machines

 Gears are also important simple machines. A gear is just a wheel with teeth, sometimes called a cog. To do any work with a gear, you need to have at least two cogs with their teeth fitting into each other. Because the teeth fit together, when you turn one gear, the other one turns too! Gears come in many different sizes, which help them do work. If you connect one big gear with a small one, you can turn the big gear slowly and it will make the little gear turn quickly. Since it takes less energy to turn the big gear slowly than it would to turn the little one quickly, you are saving energy and making work easier by using gears.

 One gear can make another one turn faster, but it can also make it turn in a different direction. When you turn a big gear to the right, the little one will move to the left. This is good for many machines where the direction needs to change in order for the machine to work.

When two or more gears are connected, it's called a "gear train." The gear that you turn is called the "driver" and the last gear that you are trying to move is called the "driven" gear. Sometimes there will be several gears in between the driver and the driven—those are called "idlers.

" Big Gears, Little Gears! 
Gears are everywhere! Some rides at an amusement park or fair use large gears which make them spin in circles (like the spinning teacup ride at Disneyland). Huge wind turbines use gears to convert the slow motion of the blades into much faster motion to make electricity.
 Gears are in small things, too, like tiny music boxes or remote controlled cars. They are used in clocks to make the minute and the hour hand go around. They are used in motors: big car motors, and little motors that make your toys move. Most of the time they are hidden away inside so you can't see them, but if you look at a can opener, you will be able to see two gears. Turning the handle will make one of the gears move, and the other one will move in the opposite direction. You can also see gears on a bicycle. With some bikes, the wheels will move at different speeds when you pedal because of gears connected by a chain.

Use this worksheet to help review the concepts of how gears change speed and direction

SCIENCE DISPLAY UNIT 7

In this Unit about Energy children from Year 6 A and B have done posters, crafts and PPTs about this topic. As you can see in our Science Display there is windmild a house with photovoltaic panels, a thermometer, a circuit a gameboard and many posters. If you have a look at this webpage in OTHER PROJECTS MADE BY STUDENTS you could know the PPTs, the word documents and the Prezys that they have done.

WELL DONE EVERYBODY!!!!!