Group items tagged

"Simple Machines: These devices were all in common use for centuries before Leonardo's time. Each one makes work easier to do by providing some trade-off between the force applied and the distance over which the force is applied."

Simple Machines: These devices were all in common use for centuries before Leonardo's time. Each one makes work easier to do by providing some trade-off between the force applied and the distance over which the force is applied.

"A machine is a tool used to make work easier. Simple machines are simple tools used to make work easier. Compound machines have two or more simple machines working together to make work easier. In science, work is defined as a force acting on an object to move it across a distance. Pushing, pulling, and lifting are common forms of work. Furniture movers do work when they move boxes. Gardeners do work when they pull weeds. Children do work when they go up and down on a see-saw. Machines make their work easier. The furniture movers use a ramp to slide boxes into a truck. The gardeners use a hand shovel to help break through the weeds. The children use a see-saw to go up and down. The ramp, the shovel, and the see-saw are simple machines."

A machine is a tool used to make work easier. Simple machines are simple tools used to make work easier. Compound machines have two or more simple machines working together to make work easier. In science, work is defined as a force acting on an object to move it across a distance. Pushing, pulling, and lifting are common forms of work. Furniture movers do work when they move boxes. Gardeners do work when they pull weeds. Children do work when they go up and down on a see-saw. Machines make their work easier. The furniture movers use a ramp to slide boxes into a truck. The gardeners use a hand shovel to help break through the weeds. The children use a see-saw to go up and down. The ramp, the shovel, and the see-saw are simple machines.

Lots of interactive physics lessons

"By 2050, a third of the people on Earth may lack a clean, secure source of water. Join National Geographic in exploring the local stories and global trends that define the world's water crisis. Learn about freshwater resources and how they are used to feed, power, and sustain all life. See how the forces of technology, climate, human nature, and policy create challenges and drive solutions for a sustainable planet."

Erosion game