There were some large-scale battles during the Vietnam War however most of the fighting was guerilla warfare. This type of warfare is different from the large-scale battles fought between armies, like those in World War II.In guerilla warfare, small units fight limited battles against an enemy force, set up ambushes, make surprise attacks, and then retreat back into the countryside or blend into the local population. It also includes making it difficult for the enemy to operate by engaging in sabotage and harassing the enemy with lethal means such as land mines and booby traps. The communist troops more often engaged in guerilla warfare against the South Vietnamese and American troops.
Although most traps were non-explosive, there were a few explosive traps which all used grenades. A trip wire was placed and if a soldier tripped over the wire, a grenade pin was pulled out and the grenade would blow, killing the soldier.
Another style of trap was nicknamed “Venus Flytrap”. It had about eight barbs attached to a rectangular frame sitting on a small hole. The barbs were facing down so when the soldier’s leg got caught in it, it wouldn’t hurt until he pulled his leg out. When he pulled his leg out the barbs would rip through his leg.
Another Vietcong trap was the Punji trap. Two wooden platforms were placed and covered with leaves to camouflage it. There were spikes on the inside of the wood. When a soldier came along and walked on the wood, it caved in and the spikes would go through the soldier’s foot. These traps were the most common because they were the cheapest and very effective. They also were often contaminated (often with feaces) so that the soldier would also become infected.
Besides hurting or killing people, these traps were good at causing fear and lowering soldier morale.
The Fall of Saigon was the capture of Saigon, the capital of South Vietnam, by the People's Army of Vietnam and the National Liberation Front on April 30, 1975. This marked the end of the Vietnam War and the beginning of the formal reunification of Vietnam into a communist state.
Before the city fell the few American civilian and military personnel left Vietnam, along with tens of thousands of South Vietnamese soldiers and civilians had fled.
North Vietnamese forces under the command of General Văn Tiến Dũng began their final attack on Saigon, which was commanded by General Nguyen Van Toan on April 29, with a heavy artillery bombardment of Tân Sơn Nhứt Airport which killed the last two American servicemen who died in Vietnam, Charles McMahon and Darwin Judge.
By the afternoon of the next day, North Vietnamese troops had occupied the important points within the city and raised their flag over the South Vietnamese presidential palace. The government of South Vietnam formally gave up shortly after.
Saigon was renamed Ho Chi Minh City, after communist leader Ho Chi Minh.
Any Americans that were in Saigon at the time were evacuated by helicopter or fixed-wing aircraft. The surrender of Saigon was told by the South Vietnamese president himself, General Duong Van Minh. He said "We are here to hand over to you the power in order to avoid bloodshed." General Minh had become South Vietnam’s president for two days as the country crumbled.
Sahel
The Sahel is a narrow belt of land in North Africa. It is a strip of land about 5500 kilometers long and 450 kilometres wide. It lies at the southern edge of the Sahara Desert
The Sahel has a tropical semi-arid climate. It is between the dry desert land to the north and the forest areas to the south. The temperature is high throughout the year. There is little rainfall in the Sahel (between 100-150 mm and 600mm). It comes during summer months and may be unreliable. It may be very dry in some years, especially if a large area of low pressure, which brings rain, is not carried North over the Sahel by strong winds.
The Sahel is the Arabic word for 'edge' or 'shore'.
The Sahel is facing a big problem, desertification.
The distribution of rainfall in the Sahel region is uneven. The rainfall in the region has been below average since 1970. The Sahel is becoming drier on the whole. The problem of drought affects most of the countries in the Sahel. As a result, crops and animals die. There is no vegetation to protect the soil, which is then removed by flash floods and strong wind. This leads to soil erosion. Finally, the desert spreads towards the surrounding areas.
With better medical services, the birth rate increases and the death rate decreases in the Sahel. As a result, the population in the Sahel is growing. To meet the ever-increasing demand for firewood, a lot of trees have been cut down. More land has become barren. This is called deforestation.
Furthermore, people farm intensively in order to grow more crops, the soil becomes infertile with a lack of nutrients. If this process continues for a long time, no crops can be grown. This is called overcultivation.
People keep animals for food due to the lack of good soil, the animals will have to eat grass and etc. But as the animals eat the grass, they also dug up the soil. As people keep too many animals, the demand for grass is too great. Soil erosion is caused while the animals keep digging the soil up as they eat, and the wind and rain blow away the soil. This process is called overgrazing.
Modern solutions can be used to give a better agricultural result in the Sahel. We can try drip irrigation or hybrid. We should stop using excessive water and consider our actions, to save the Sahel and lake Chad before it is too late.
Chemical change
A chemical change (chemical reaction) is a change of materials into other materials with different properties.
Chemical changes occur when a substance combines with another to form a new substance, or, chemical decomposition into two or more different substances. These processes are called chemical reactions.
Burning of wood is a chemical change as new substances which cannot be changed back (e.g. carbon dioxide) are formed. For example, if wood is burned in a fireplace, there is not wood anymore but ash. Other examples include burning of a candle, rusting of iron, baking a cake, etc. Special details that describe how a chemical change takes place are called chemical properties.
Compare: physical change. The opposite of a chemical change is a physical change. Physical changes are a change in which no new substances are formed, and the substance which is changed is the same. For instance, if a stick of wood is broken, there is still a stick of wood; it is just broken.
More examples include changes of shape, changes of states, passing electricity through a copper wire, breaking of wood, shattering of glass, pouring of water, etc. Special details which do not change in a substance without new substances being formed are called physical properties.
Physical change
A physical change is a type of change in which the form of matter is altered but one substance is not transformed into another. The size or shape of matter may be changed, but no chemical reaction occurs.
All physical changes are reversible and their mass does not change. Some examples are changes of shape, changes of states, and passing electricity through a copper wire. Physical changes could be: melting, freezing, boiling/evaporating, condensing, deposition and sublimation.
Many physical changes also involve the rearrangement of atoms most noticeably in the formation of crystals. Many chemical changes are irreversible, and many physical changes are reversible, but reversibility is not a certain criterion for classification. Although chemical changes may be recognized by an indication such as odor, color change, or production of a gas, every one of these indicators can result from physical change.
Ronald Reagan