Asample of gas with a thermometer immersed in the gas is held over a hot plate. a student is asked to give a step-by-step account of what makes our observation of the temperature of the gas increase. his response include: (a) the molecules speed up. (b) then the molecules collide with one another more often. (c) internal friction makes the collisions inelastic. (d) heat is produced in the collisions. (e) the molecules of the gas transfer more energy to the thermometer when they strike it, so we observe that the temperature has gone up. (f) the same process can take place without the use of a hot plate if you quickly push in the piston in an insulated cylinder containing the gas

the independent variable, or the one that is intentionally manipulated is the speed.

bacteria that live on the ocean floor are sustained by phytoplankton. phytoplankton, microscopic marine photosynthetic organisms, have a vastly significant role to play not only in the marine food web of which they’re part of, but also on a more global scale. despite their infinitely small size in comparison to other marine organisms, these tiny creatures occupy an immensely important ecological niche: they are the foundation of the marine food web, and as primary producers, play key roles in supporting all other organisms in the marine environment, as well as in the regulation of the earth’s climate through the sequestration of carbon, oxygen production, and other related processes. phytoplankton account for roughly half of all global primary productivity; therefore, their significance extends far beyond the marine environment alone. there is an intriguing sense of irony in the realization that these tiny living beings that often live out their existence unnoticed and undetected by the rest of the world, have such a far-reaching impact on the lives of virtually all other living organisms on the planet, particularly on those in the marine environment. the world that we have become accustomed to has been and is continuously shaped by the workings of these miniscule yet vital “plants of the sea”.

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