Wave Interference

Anyone who as watched the surface of a swimming pool has observed wave interference. Wave interference occurs when two or more waves move through the same space at the same time. Unlike solid matter, waves move through each other. The principle of superposition describes the response of a medium being displaced by more than one wave.
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Balancing Chemical Equations

In chemical reactions, sets
of compounds interact with each other to form new compounds. Chemists use equations to describe these interactions. Like mathematical equations, chemical equations conform to a set of rules. This allows equations to provide detailed information about a reaction.
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Covalent Bond Energy

Eating, putting gas in a car and throwing a log on a campfire all involve adding energy to a system. In each case, the energy is added in the form of covalent bonds that hold atoms together in molecules.

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Metric System Unit Prefixes

Similar to scientific notation, unit prefixes make very large and very small number easier to manipulate and to understand.

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Scientific Notation

Some people have a strong resistance to using scientific notation. Almost every time I teach an introductory science class, I have one or two students with good math skills who insist on doing all of their calculations in standard notation. Doing this invariably results in mistakes that lead to lost points on exams and homework.

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Serial Dilutions II

***UPDATE- View the updated illustration at SciencePrimer.com


Serial dilutions are a common part of may laboratory procedures. Background on serial dilutions, how they are performed and calculation of dilution factors are covered in a previous post.

The following illustration extends the exploration of serial dilution by following changes in the volume and concentration of a solution over three dilution steps.

Pendulum Period

Clocks with quartz movements are more accurate at keeping time than those that use pendulums. Quartz has largely replaced pendulums in modern clocks. But, in their day, pendulum clocks were profoundly important due to their ability to measure time accurately over long periods. The first pendulum clocks were produced in the mid 17th century and their impact was dramatic. Their use ushered in a new era of accurate time keeping. The reliability of pendulum clocks is based on the predictable relationship between the length of a pendulum and the time it takes the pendulum to complete one full swing.
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