The ceiling of a single-family dwelling in a cold climate should have an R-value of 49 ft2 ·F°·h/Btu. To give such insulation, how thick would a layer of (a) polyurethane foam and (b) silver have to be? The thermal conductivity of polyurethane foam is 0.024 W/m·K, and the thermal conductivity of silver is 428 W/m·K.

What produces a record of seismic waves? richter scale seismogram barometer seismograph

Imagine that you have two balloons (or, better yet, actually inflate two balloons, if possible). create static electricity around one of the balloons by rubbing it against your hair or your sweater and then bring that balloon close to the other balloon, which has not been charged. try this with at least one other object—and for variety in the discussion, avoid using an object already described by your classmates. then, for your initial post to the discussion, answer the following questions: what happened with the two balloons?

Galileos view of arrangement of the universe