Science, Technology and the Environment (SC NATS 1840A) - Tuesday
October 9th, 2012
Readings: 3.3, 3.5, 3.6 Activity # 3 Electronic Copy of experiment to turnitin.com
The cycling of Matter & Energy in the Environment
Living organisms consume nutrients and energy to thrive.
Six “macronutrients” are constantly recycled – Carbon, oxygen, hydrogen, nitrogen, phosphorus,
Biogeochemical cycles: physical & chemical processes which ensure the exchange of matter & energy
between the biotic and abiotic parts of the ecosphere.
To understand these cycles, we must understand the nature of matter and energy.
Part 1 – Matter
Matter, Elements and Atoms:
Matter: Anything that takes up space and has mass.
Composed of atoms of elements which interact chemically with one another to form more
complicated molecules of compounds.
Elements: Basic chemical constituents of matter, i.e. the stuff from which all things are made.
Each element has distinct physical properties;
Elements cannot be further broken down by chemical means.
Atom: Basic physical unit of an element, i.e. smallest piece of matter that exhibits the properties of that
The physical characteristics of an atom determine the properties of the corresponding element.
Atoms themselves are composed of tiny sub-atomic particles.
Protons => The basic constituents of all atoms.
Neutrons => Structure of an atom: Small, dense nucleus of protons and neutrons, surrounded by large, diffuse cloud
of electrons. Size: about 10^-10 meters.
Each sub-atomic particle carries a specific electric charge. The electromagnetic force acts between
charged particles, exerting a force which depends on the charges involved.
Two positively-charged (+, +) or two negatively-charged (-,-) particles repel each other.
Two oppositely-charged (+,-) particles attract one another.