Tuesday - February 1st - Week #23 -
- Science guest speakers today … The theme was “Waves.” Especially earthquake waves. We’ve begun Human Body Systems - as we saw an example of an EKG yesterday. Seventh grade science standards covers everything from evolution to engineering. One of the most important concepts, that cuts through all we’ve learned, is understanding periodic motion and waves. Some of our connections and highlights.
- On of our first experiments, this year, was with a simple pendulum. We changed the length of string and the mass and discovered that it’s the string, not the mass, that determines the PERIOD of the pendulum.
- Graphing this information on a Cartesian Coordinate System helps us understand INDEPENDENT and DEPENDENT variables and helps us make predictions based on trends we see in the data.
- Moving on from pendulums we studied light and the speed equation. (Speed = distance / time) - Light (electromagnetic waves) move at the ultimate speed limit of the universe; 300,000 kilometers per second. This “speed limit” leads to some startling consequences. Since the SPEED of light is limited, this means that TIME and DISTANCE must change to accommodate the speed of light (c.) In other words, the speed of light is constant for ALL observers! Thanks Einstein :-)
- Water waves (surfing, ocean, tides, etc) obey the same equations of light waves in terms of FREQUENCY, VELOCITY, and WAVELENGTH.
- Waves are important when we study the ELECTROMAGNETIC SPECTRUM. Our standards touch on this when we delve into photosynthesis and the frequencies of light used by plants in releasing oxygen to our atmosphere and making sugars.
- Again, waves are seen when studying RADIOACTIVE DECAY - an important process for not only maintaining the internal heat of our planet but for scientists in determining the age of fossils and non-living minerals. This helps provide evidence for both PLATE TECTONICS and the immense time needed for EVOLUTION.
- Today, we reviewed our local connections with earthquake waves as our classroom is adjacent to the San Andreas Fault, a major player boundary. Earlier in our year we used to RATE of movement of the San Andreas Fault to predict when Los Angeles and San Francisco will be next to each other.
- We’ve touched on SOUND WAVES and will return to these when we go back to our first month and understand how Edwin Hubble used the DOPPLER EFFECT to calculate the speed with which out universe is expanding, leading to the BIG BANG theory.
- Current physics research into the fundamental nature of our universe relies on an understanding waves as scientists try to reach a Grand Unified Theory through STRING THEORY.
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