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Mixtures and Compounds in Living Organisms 150 150 Deborah

Mixtures and Compounds in Living Organisms

Overview Mixtures and compounds are important combinations of elements.  They are essential to the chemical processes that support living things, as well as those that occur every day in nonliving objects.  The basic difference is that elements and molecules in mixtures remain the same substances, and compounds result from chemical reactions, forming chemical bonds. Solutions…

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Structure of Cells 150 150 Deborah

Structure of Cells

Overview:  What Are Cells? Most cells are too small to be seen without a microscope, so theories about them did not exist until after microscopes were in use.  A scientist named Hooke called the small structures in a thin slice of cork “cells”, but it wasn’t until the 1800s that cell theory was really put…

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Microscopes: From Light to Electron 150 150 Deborah

Microscopes: From Light to Electron

Overview:  The Microscope The microscope is a valuable tool in biology and other sciences.  It allows investigators to study many objects that are too small to be seen with eyes alone.  While many observations can be done with simple and compound light microscopes, the smallest details are shown with electron microscopes. Simple Light Microscopes The…

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Spontaneous Generation and Biogenesis: The History of Biology 150 150 Deborah

Spontaneous Generation and Biogenesis: The History of Biology

Overview:  Scientific Belief in Spontaneous Generation Great thinkers in ancient times thought that life arose spontaneously in areas where there wasn’t anything living that they could observe.  For example, Aristotle believed that some fish were made from the muddy sediment at the bottoms of rivers and oceans.  Before the invention of microscopes, eggs that were…

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Linear Systems in Algebra 150 150 Deborah

Linear Systems in Algebra

Overview:  Solving Linear Systems In order to solve systems of two sentences, the solution has to be true for both sentences.  For example, the solution of a problem such as 2x-3y=13 and 3x +y = 3 has to work fox x and y all throughout the problem.  Linear systems can be solved by graphing, by…

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Congruent Figures 150 150 Deborah

Congruent Figures

Overview:  What Are Congruent Figures? Geometric figures are congruent if they have exactly the same size and shape.  This means that their sides are all the same size and their angles are all the same measurements.  They differ from similar figures, in that similar figures have angles with the same measurement,  but the measurement of…

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Similar Triangles 150 150 Deborah

Similar Triangles

Overview:  What Are Similar Triangles? Two triangles are similar if they each have two angles that have the same measurement, and the lengths of the corresponding sides are proportionate.  Therefore, one triangle can be made to measure the same as the other one by multiplying each side by the same factor.  For example, given two…

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A Physics Review of Subatomic Particles 150 150 Deborah

A Physics Review of Subatomic Particles

Overview:  What Are Subatomic Particles? Subatomic particles include those particles smaller than an atom.  Some of those particles are charged, such as protons, which have a positive charge, and electrons, which have a negative charge.  Some particles have brief lifetimes, and have only been observed since the development of particle accelerators.  These form the basis…

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Chemistry and Biology Review: Life in Oceans of Europa? 150 150 Deborah

Chemistry and Biology Review: Life in Oceans of Europa?

Overview:  Why Europa? Europa is one of the moons that orbit the planet Jupiter.  Recently, scientists studying data from the faraway moon have applied principles of biology and chemistry to suggest that some of the conditions for life may be present in that moon’s oceans.  They have studied the chemical exchange between the  ocean and…

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The Chemistry and Physics of Superconductors 150 150 Deborah

The Chemistry and Physics of Superconductors

Overview:  What Are Superconductors? Superconductors are substances that do not resist electrical flow at all when they are cooled below a certain temperature.  Electrical currents can flow indefinitely without using extra voltage; and no energy is lost to heat.  Those properties make superconductors very efficient when used in devices such as MRI magnets, mass spectrometers,…

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