04.17.2020 - Friday - Science Notes -
Please remember, as always, the define the terms that are CAPITALIZED.
- Current Events - Link … https://www.cnn.com/cnn10
- Two notes on “Space Tourism.” Remember when we saw the brief video clip of Joe Kittenger traveling to the edge of space? He was the Airfare Colonel who parachuted back to Earth from over 100,000 feet!
II. The Oxygen Cycle:
A. Oxygen - One of the “Big Four” elements that are essential for life (the other three being Carbon, Hydrogen, and Nitrogen) also cycles through the Earth and atmosphere, driven by the sun and by the internal heat from planet Earth!
B. Oxygen cycles through the ATMOSPHERE, BIOSPHERE, and LITHOSPHERE.
C. Oxygen is very reactive. This means that when an oxygen MOLECULE is “floating around” it tends to REACT and combine with other ELEMENTS.
D. Many people think that our atmosphere is almost entirely made of oxygen. Actually, Our atmosphere is mostly comprised of nitrogen!
E. At sea level, about 21 percent. This means that, every time you take a breath, about 1/5 of that breath is oxygen. The rest is Nitrogen, along with some other gasses in much smaller amounts (like Carbon Dioxide or even a very rare gas called Argon.)
F. Tiny ocean plants (and protists) produce somewhere between half (50 percent) and three-fourths (75 percent) of the oxygen we breath! The main photosynthesizes are;
G. Review: Write the CHEMICAL EQUATION for PHOTOSYNTHESIS here … be sure to labels the REACTANTS and the PRODUCTS.
III. Because oxygen is so REACTIVE, and tends to combine with other ELEMENTS, it is often found in rocks in our LITHOSPHERE.
A. One way we are looking for life beyond Earth is by studying the atmosphere’s of distant plants.
B. Only recently have scientists been able to observe planets that orbit other stars besides our sun. When your science teacher was growing up the text books and teachers taught us about “the nine planets.” Now, we teach about the EIGHT PLANETS, several “minor” planets, and we have discovered thousands of EXTRASOLAR PLANETS! These are planets that are much too far away to visit with our technology, because they orbit other stars!
C. Review: Remember, there are about 200 billion stars in our galaxy, the Milky Way. There are about 200 billion other galaxies too! Thats quite a few stars!
D. Scientists look for OXYGEN in the atmosphere of these EXTRASOLAR planets. If we find free oxygen, then there might be PHOTOSYNTHESIS going on there as well! (Whoa!)
E. We’ll learn about how we can tell what elements are in other atmosphere’s even though we are very far from them … (Hint: It has to do with light!)