Globe is to facilitate people to understand the earth, people imitate the shape of the earth, according to a certain proportion, made the model of the earth-globe. There are deformations in length, area, direction and shape on the globe, so it is almost correct to observe the relationship between various scenes from the globe.

A globe is a model of the earth. Although it can't show all kinds of geographical things and phenomena in detail like a map.

Globe (2 pieces)

Elephants can't fully reflect the actual situation of the earth, but they can avoid errors and distortions in the length, direction, area or shape on the map, and help us to sort out many related concepts of the earth and get the main concepts of the earth.

Demonstrate the deflection force of the earth's rotation

In order to observe the rotation deviation of the earth, we can use a globe to make the axis of the earth perpendicular to the ground plane, turn the north pole of the globe upward, and drop one or two drops of red ink at high latitudes in the northern hemisphere. When the globe does not rotate, the red ink will flow along the meridian to the low latitude, leaving ink behind. Then you turn the globe from west to east, and then drop a drop or two of blue ink at high latitude, and you will find that the flow direction of blue ink has changed to the right compared with the original flow direction of red ink. Similarly, turn the globe sideways, with the south pole facing up, and make two demonstrations in the same way. Through comparative observation, it can be seen that the trajectory of blue ink flow is shifted to the left relative to the trajectory of red ink flow.

Then put the globe still and flat, the earth axis is parallel to the horizon, drop one or two drops of red ink on the equator, and find that the flow direction of red ink is along the equator line; Then drop a drop or two of blue ink into the original one and turn the globe. It is found that the flow trajectory of blue ink is consistent with that of red ink, indicating that its flow trajectory is not affected by the rotation of the earth. Therefore, it can be clearly seen that under the action of geostrophic deflection force, the deflection law of horizontally moving objects is: right deviation in the northern hemisphere, left deviation in the southern half of the day, and the equator does not deflect.

Day and night alternate demonstration

Draw the sun with electric light or strong flashlight, so that it is on the same plane as the center of the earth. The earth rotates around its axis from west to east (the northern end of the axis points to the north). The period of the Earth's rotation (3600 revolutions) is a sidereal day, that is, 23 hours, 56 minutes and 4 seconds. When the earth rotates from west to east, it rotates counterclockwise from the North Pole. Seen from above the Antarctic, the earth rotates clockwise; Seen from above the equator, the earth rotates from west to east. These three statements are consistent. Because the earth (instrument) is an opaque sphere, the sun (electric light or strong flashlight) can only illuminate half of the earth at the same time, that is, the sun is daytime and the back is night. The hemisphere illuminated by the sun (electric light or strong flashlight) is called the daytime hemisphere, and the hemisphere illuminated at midnight is called the night hemisphere. The dividing line (two lines) between two fighting balls is combined into a circle, which is called the end line (circle). When the earth (instrument) rotates continuously from west to east, we will find that the direct point of the sun sweeps from east to west, and the morning and evening circles move regularly from east to west, so the day and night on the earth will change constantly. The globe has been turning from west to east, which can prove that day and night alternate regularly on the earth.

Determination of local time and time zone

Those of us who often use the globe will find that at the north end of the globe axis, there is a "time gauge" made of round metal sheet, half of which is painted black to indicate night; The other half keeps the metal primary color, indicating sunlight. On the two semicircles, carve 24 moments counterclockwise every 15. The timetable on the globe can be used to measure the local time and time zone. When in use, the timer can be wound.

artware

The calculation method and steps of Arctic rotation are as follows:

(1) local time. For example, if the local time in Suzhou (12 1 E) is known as 12, what are the local time in Wuhan (106 E) and Urumqi (9 1 E)? During the demonstration, first turn the "Timetable" and aim the longitude of Suzhou at 12. At this time, we can find that the local time in Wuhan is 1 1 point, and the local time in Urumqi is1point.

(2) Determine the time zone of the book. For example, at Beijing time (using the East Eighth District) 12, find the East 10 and West 2 districts. During the demonstration, align the scale of 12 on the timetable with the central meridian of East Zone 8 (120 E), and you can find and read out on the timetable that East Zone 10 (the alignment time of 150 E) is 14. The central meridian degree of each time zone is the number of zones in this area multiplied by 150. East longitude is east longitude and west longitude is west longitude.

(3) Measure the area on the warp line of the book. For example, when Beijing time (using East 8 time zone time) is 12 am, find the time zones of West longitude 10 and West longitude 8 1. Since longitude 10 and longitude 8 1 are not on the central meridian of the time zone, we must realize that each time zone spans longitude 15, and its range is 7.5 on the west side of the central meridian. During the demonstration, align the scale of 12 on the timetable with the central meridian of East Zone 8 (120 E), and then you can find out the nearest two central meridians (the longitude difference is less than 7.5) 10 W and 8 1 W on the timetable.

Determine the relative position between two points on the earth

To determine the position of one place on the earth relative to the local (another place), we must first determine the local meridian on the earth; Then determine the direction line from local to somewhere; Finally, measure the angle between the local meridian and the direction line. That is, the orientation of a place relative to the local area. The specific measurement method is as follows:

1. Insert a needle in the local position on the globe, and then rotate the globe so that the needle coincides with the radius scale (that is, the semicircular bracket of the globe); The radius scale is the local north-south line, which is the prime meridian.

2. Determine the direction line from local to somewhere.

3. Measure the included angle between the local meridian and the local direction line with a protractor, and attach the azimuth. See the figure on the right for the specific orientation name. Calculate the distance between two places on the surface.

Measure the field distance between two locations on the surface.

The method is as follows:

1. Measure the circumference of the equator (in millimeters) on the globe with tight and small elastic thread, thin metal wire or paper strip, and then calculate the scale of the globe according to the formula (some globes have been marked with standard scales, so this step can be omitted). The linear scale of the globe = the distance on the map/the distance on the ground, that is, the circumference of the equator on the globe (mm)/ the actual length of the equator on the earth (that is, 4075704 million mm), so the linear scale of the globe can be calculated).

2. Then use the above method to measure the distance (mm) between any two places on the globe and divide it by the linear scale of the globe to calculate the actual horizontal (actually spherical) distance between the two places. You can also measure the distance (arc length) between any two places on the globe first, then measure the radian of this distance with the scale of the equatorial circle on the globe, and then multiply the measured radian by11.1.65438km (11).

According to this method, you can also make a ruler for measuring the distance between great circles with a piece of paper or metal with the length equal to the equator, divide it into 360 equal parts, and each equal part can be directly converted into a scale of kilometers, so that you can directly measure the shortest distance between any two places (that is, the spherical arc distance) and the distance between aviation and navigation lines on the globe.

Calculated area

First, the grid method

First, according to the linear scale of the globe, calculate the scale of the area. The area scale is the square of the linear scale. For example, the linear scale of 1cm represents the field distance of 200km and 400km, and the area scale of 1cm2 represents 40000km2 and 160000km2. Then, use transparent paper with a square of cm to lay it flat on the globe to be measured. Firstly, the number of complete squares in the measurement area is calculated, then the incomplete squares are assembled (visually) into several complete squares, and finally the total number of squares (that is, the number of square centimeters) is accumulated and multiplied by the square kilometer represented by 1cm2, which is the actual area of the measurement area. For example, the area ratio of a globe is 1cm2, representing 40000km2 and 160000km2 respectively. When the measured area (such as Egypt) is 48.5cm2 and 6.25cm2, the field area is 40000 km2× 48.5 =1940000 km2 and 1600000. This method can be used to measure the area of the earth with small scope and complex outline, for example, the area of African countries can be measured by this method.

Second, the trapezoidal method

This method is to measure the actual area of the measured area by using the trapezoidal area surrounded by the latitude and longitude net on the globe. It can be used to measure the area of a large area on the earth. The trapezoidal area between two adjacent weft yarns is equal; The trapezoidal area between different latitudes decreases with the increase of latitude.

Trapezoidal method is used to measure area. Firstly, the trapezoidal number of the measured area of each latitude zone on the earth is estimated, then multiplied by the trapezoidal area of that latitude zone, and then added one by one to get the total area.

There are about 13 trapezoids between latitude 0- 10, covering an area of 7962500km2.

There are about 7 trapezoids between latitude 10-20, with an area of 4 16 1500km2.

There are about 5.5 trapezoids between 20 and 30 latitudes, with an area of 3071750km2; .

There are about three trapezoids between 30 and 40 degrees north and south latitude, with an area of1518000km2;

There are about two trapezoids between latitudes 40-50, covering an area of 876000km2.

There are about 1.5 trapezoids between 50 and 60 latitudes, covering an area of 534000km2.

Adding up the above trapezoidal areas, the area of South America is about 18 123750km2.

I hope it can help you solve the problem.