Heat supplies the energy that causes motion. The deeper you go into toward the Earths core, the hotter it gets. At the core it is really hot. All that heat tries to rise toward the surface. In the Mantle, the rock is partially melted and is able to move. As it is heated, the material in the mantle moves toward the surface. As the mantle material rises, it cools. When it reaches the Earths crust, it is mostly stopped. A little of the material can break through the surface, but not all. Instead, it begins to move horizontally. The mantle material moves horizontally away from a mid-ocean ridge crest. Toward the surface, the mantle material starts to cool. As it cools it sinks back down into the mantle. These areas are where deep sea trench occur. The material sinks back down to the core. The system operates like a giant conveyor belt. The motion due to heating and cooling is called convection.

Why does the system work as a conveyor belt?

A married couple and their three young adult children , a son and two daughters , live in a large compound with a garden and a swimming pool . A tall fence surrounds the property and the children have never been on the other side of it , for their parents have kept them unaware of the outside world , even of the existence of the telephone . They are taught different meanings for everyday words . For example , they are told that a '' zombie '' is '' a small yellow flower , '' and that '' sea '' is a chair . The parents promise that each child will be ready to venture outside the compound once she or he has lost a dogtooth . Although the children are told they have a brother just on the other side of the barrier , he never appears . The only non-family member to come into the house is Christina , a young woman who works as a security guard at the father's factory . She is driven by the father to the compound traveling both ways blindfolded where she performs sexual favors for the son . Dissatisfied with his preference for intercourse , Christina seeks oral sex from the elder daughter in exchange for a headband. The elder daughter obliges but does not recognize the significance of performing cunnilingus . Later , she gives the headband to her younger sister , in exchange for being licked on the shoulder , Which is marked by an unexplained scar . The parents have tricked the children into believing that overhead planes are merely toys . They allow the children to search for toy planes that they have planted on the grounds , and the child that finds the toy owns it .

Are the parents honest with their children?

Milwaukee, Wisconsin (CNN) -- President Barack Obama, in a bid to create jobs and boost economic growth, called on Congress on Monday to pass a $50 billion plan to renew the country's transportation infrastructure. His address was the first of two speeches the president is scheduled to make this week to frame his administration's ongoing response to the recession, less than two months ahead of midterm elections in which Democratic majorities in the House and Senate are in jeopardy. "Today, I am announcing a new plan for rebuilding and modernizing America's roads, and rails and runways for the long term," said Obama, who spoke on Labor Day in Milwaukee, Wisconsin -- a state with competitive gubernatorial and U.S. Senate races. "We used to have the best infrastructure in the world. We can have it again," he said to loud cheers from a crowd of union workers. The proposal envisions -- over a six year period -- rebuilding 150,000 miles of roads, 4,000 miles of rail and 150 miles of airport runways. It also would include modernizing the nation's air traffic control system in an effort to reduce delays and travel time. "This will not only create jobs immediately. It's also going to make our economy hum over the long haul," said the president. Obama hopes to work with Congress to enact an up-front investment of $50 billion -- an amount a White House statement said would represent a significant chunk of new spending on infrastructure. The investment would then be paired with what the administration called a framework to improve transportation spending. The long-term plan would include the establishment of an Infrastructure Bank, which would leverage federal dollars and focus on projects that could deliver the the biggest bang for the buck, Obama said. The president stressed the need for Democrats and Republicans to work together on the transportation initiative, which would need to be approved by Congress.
What is the framework to improve transportation spending?