The pump, which is about the size of a grain of raw sugar, is thermoelectric. Several thousand of the tiny pumps would be required to heat up an average-size home.
Underground mass-transit lines are expensive to build, but they are the most efficient form of transportation in major cities. Today about 145 cities in more than 50 countries have a subway system.
Using one of these artificial external skeletons, wheelchair users may someday walk by themselves. These motorized limbs may even make navigating staircases possible.
The global average temperature is calculated using thermometer measurements. Thanks to a grid system, scientists are able to compensate for geographical irregularities.
