Science - Week #9 -
The Martian - recap - tie-ins with the notes.
- Newton’s Laws: Students were asked why the “Hermes” can’t simply turn around and get Mark Watney - Inertia and Newtons Laws - space ships carry very little fuel once they’ve used the bulk of their propellent to reach space.
- Friction - Scientists guest visit on Thursday highlighted FRICTION. In space there’s almost no friction. Once the Hermes starts back towards Earth, Newton’s First Law tells us the ship will travel at the same speed for the several-month journey home.
- Watney has to travel more than 3,000 kilometers and stay warm on his journey. (That would be like taking a rover from San Francisco to Kansas.) Recall our unit on RADIOACTIVE ISOTOPES: Watney digs up an old radioactive battery. (Radioactive batteries are used for space travel because they are long-lasting.) While not good as a battery, any more, decaying radioactive isotopes still release HEAT. Recall “Uranium.” By Derek Muller.
- LIGHT: The SPEED OF LIGHT is a constant. (300,000 kilometers per second - That’s 186,000 miles per second.) Students were challenged to find the time for a radio signal to go between Earth and Mars. (The distance between the two planets can vary from 50 million kilometers to 400 million kilometers.) Use the version of the SPEED equation where TIME is by itself and “pop” in the values (Speed of light and distance.) It can take from, about, five to 20 minutes for a signal to go between Earth and Mars. (Remember - Radio waves, Microwaves, Gamma Rays, X-Rays, etc. are all forms of LIGHT.)
- Chemistry - ORGANIC MATERIAL - Watney uses human waste to turn Martian DIRT into SOIL. Recall “The Biggest Little Farm.” Microorganisms are essential for growing plants - in his case, potatoes. A starchy tuber. Overall, experiments show it IS possible to grow potatoes in the way shown in the movie. However, a diet of only starch would not have protein or fats and a person would - quickly - lose a great deal of muscle mass.
- Chemical reactions: Watney (Matt Damon) burns Hydrazine (rocket fuel)using a CATALYST. Catalysts help a chemical reaction to occur (recall catalytic converters). Similar to the reaction we studied with HYDROGEN burning to yield WATER and heat.