Why do your feet feel hot after touching them to hot sand or pavement?

Energy derived from hot rocks and fluids beneath the earth’s surface is

What was dr. willem johan kolff’s first step in using the scientific process to invent the hemodialysis machine? he built the machine and tried it with various patients, collecting data about its effectiveness. when a patient’s kidneys failed, he wondered if it would be possible to perform kidney functions with an external machine. he researched and collected data about numerous patients who exhibited symptoms of kidney failure. he drew conclusions from studies of various symptoms of kidney failure, and drew a design for the ideal external blood-processing machine.

How does buring fossil fuels impact does carbon cycle? what large impact does this have on the envirnment?