Geography

Hydraulic action - water crashes into gaps in the soil and rock, compressing the air and forcing particles apart.

Abrasion - the flowing water picks up rocks from the bed that smash against the river banks.

Attrition - rocks carried by the river smash against one another, so they break down into smaller and more rounded particles.

Corrosion - minerals such as calcium carbonate (the main part of chalk and limestone rocks) are dissolved in the river water.

Solution - Soluble minerals are dissolved in rocks or in the soil and carried along in the flow of the river.

Suspension - Small particles are carried long distances in the flowing water (occurs in most rivers, except the slowest).

Saltation - Sand and small gravels bounce and skip along the river bed (occurs in the most energetic rivers with high velocities).

Traction - Large gravels, cobbles, and boulders roll along in contact with the river bed (only occurs in high energy river channels or during flood events).

This occurs when the river loses its energy or in shallow waters where friction of the water with the river bed causes the river to lose its energy, meaning it deposits its load.

Deposition creates layers of sediment that are often sorted by sediment size because the coarsest sediment is deposited first.

Erosion is most likely to take place on the outside of a meander as this is where energy is at its highest.

Deposition is most likely to occur on the inside of a meander as energy is lost.

MDGs are Millenium Development goals. In 2000, the UN set eight MDGs to help encourage and assist human development. The challenge is to meet these goals by 2015.

To end extreme poverty and hunger.

It's targets were to:

• Halve the number of people living on less than a dollar per day.
• Halve the number who suffer from hunger.

Achieve universal primary education.

It's targets were to:

• Ensure that all boys and girls complete a full course of rpimary education.

Promote gender equality.

It's targets were to:

• Make it easier for girls as well as boys to access primary and secondary education.

Reduce child mortality.

It's targets were to:

• Reduce by two thirds the number of children who die before their fifth birthday.

Improve health for mothers.

It's targets were to:

• Reduce by three quarters the number of women who die in childbirth.

Combat AIDS, Malaria and other diseases.

It's targets were to:

• Halt and begin to reverse the spread of these killer diseases.

Ensure environmental sustainability.

It's targets were to:

• Protect the environment, so that future generations can continue to benefit from it.
• Halve the number of people without any access to clean water.
• Improve the life for 100 million people who live in shanty towns by 2020.

Build Global partnerships for development.

It's targets were to:

• Make improvements to aid.
• Boost freedom, justice and democracy.
• Make it easy for the poorest people to have access to medicines.
• Cancel some debts and reduce others.
• Make world trade fairer.

The physical and human growth of towns and cities.

One factor is people moving from rural areas to urban areas (normally in search of a better life, better job and more money)

The other factor is the natural increase of the urban population due to there being more births than deaths.

Refugees move because conflicts or natural disasters may mean that they have no other choice.

Economic migrants move because they are searching for a better standard of living and job. They normally believe that they will find better access to clean water and healthcare facilities.

Most people move for economic reasons than for violence and natural disasters.

Many migrants opt not to make a perminant move to the city, but they leave rural areas when there aren't many jobs or many ways of earning money to work in the city, when, for example, it is harvest and they can get a job, they return to the rural areas.

Migrants earn money which can be sent back to the rural areas for improving the farm: repairing terraces and in tree planting schemes.

When migrants leave it also reduces the food and water supply. This is very helpful in places that have long dry seasons.

It is obviously a big contributor to the spread of AIDS and other diseases. People will ocme back from the urban areas unaware that they have AIDS, and then give it to someone at home. It is much harder to treat AIDS in rural areas than urban areas because there is isolation from healthcare.

This mainly occurs in MEDCs. It is when people migrate from larger cities to smaller towns and villages in the countryside.

• The city is often seen as a stressful place to live and work.
• Lack of open space for children to play safely.
• Pollution.
• High crime rates.

It has become easier to do this because better road systems have been put in place, and they are forever improving.

Also, better transport connections that reach further out to rural areas now exist and this makes it possible to commute by public transport.