Coastside Science

Thursday, October 30, 2025

Thursday - Science and Math - October 30th - "The Martian - Part II"

The Martian - Part II -

As we began our next day of catching scenes from “The Martian” the director of NASA makes the worst mistake a person can make in any movie; to paraphrase he said, “This will work out, as long as nothing goes wrong …”

Soon after this scene, the Hab breaks and exposes Watney’s potato crops to the Martian atmosphere.

Unpacking this one scene there are several reasons plants would die on Mars;

First, the extreme cold. The average surface temperature on Mars is -40 degrees Celsius. Side note; negative forty degrees is the point at which the Fahrenheit and Celsius temperature scales “meet.” It’s the same temperature.

The atmosphere on Mars is composed, mainly, of Carbon Dioxide. While that sounds like it might be a wonderful environment for plants - as PHOTOSYNTHESIS converts carbon dioxide and water into sugar and oxygen - the atmospheric pressure is so low that any water would boil away - and then freeze - on Mars. Think about boiling water on Earth. The cooking instructions always call for more boiling time at higher altitudes as water boils at a lower temperature the higher you go. You can think of it as there being less atmosphere to hold in the water. As the average kinetic energy for the water molecules rises high enough, the water molecules can escape the mutual attraction they have with the other water molecules.

The second half of The Martian, and especially the last act, are excellent illustrations of Newton’s Three Laws of Motion.

When the mission to resupply Watney with food, until the next mission can reach Mars, fails the Chinese Space Agency offers a rocket to help with another attempt. However, the flight director - “Mitch Henderson” played by Sean Bean - knows how close this crew is and he defies orders and gives an alternative plan to the Hermes crew. A plan that illustrates how space travel really works in that the Hermes uses the gravity of Earth to “slingshot” back to Mars in order to pick up Watney. Our spaceships would not have nearly enough fuel to simply turn around and go back. Our probes reach other planets after being launched in rockets the size of buildings. Once they have an initial “push” they often carry only a small amount of fuel or gas to maneuver and make small adjustments to their trajectory. (Direction and speed.)This is a wonderful illustration of Newton’s First Law - INERTIA.

Newton’s Second Law - F=MA - is wonderfully illustrated when Watney is asked to make the Mars Assent Vehicle (MAV) as light as possible in order to rendezvous with his returning crew mates. As thrust is a CONSTANT the MAV will have the best chance of achieving a high velocity (speed) with as little weight (mass) as possible. Watney removes as much of the ship as possible; even going to the extreme of taking the front of the ship off. The front, on Earth, is mentioned as weighing close to one thousand pounds. However, as Mars has far less mass than Earth, it would only weigh about 300 pounds on Mars. Still heavy; but manageable. This cycles back to why Earth has been able to maintain an atmosphere and internal heat while Mars has no Plate Tectonics, a very thin atmosphere, and very little in the way of resources to maintain life.

Finally, when we wrap up The Martian, Newton’s Third Law is on display when the Hermes - the ship carrying his crew mates - has to find a way to slow the ship so it can intercept the MAV with Watney aboard. The crew opens a hatch and releases some air in their direction of travel. Newton’s Third Law - Action / Reaction. As the gas (air from the ship) is released in one direction the ship feels a push in the opposite direction.

Whatney, as well, uses air as thrust when he deliberately breaches his own space suit in an attempt to reach his friends and the safety of the Hermes.

The movie does stretch some science about what might be possible in terms of surviving on Mars, but the story does a wonderful job of not only illustrating physical laws and chemistry - but the incredible planet we live on and the importance of cherishing and maintaining the ONE place in the entire universe where life is known to thrive; EARTH.

Tuesday, October 28, 2025

Week #12 - Math and Science Notes plus our Tuesday sceince reading on "The Martian."

The Martian - Science Notes -

The opening scene is meant to highlight the differences between Mars and Earth as we see a very red landscape followed by people in space suits collecting samples on the surface of Mars. When Earth is shown it always highlights the verdant land and the blue oceans while the oxygen on Mars is chemically bonded to minerals making for a rusty desert plant.

A wind storm sweeps in, separating one of the astronauts from his friends, as his friends make it to the safety of a rocket and cut their stay on Mars short to escape the storm.

While large wind storms do, sometimes, cover vast areas of Mars the force of the wind would be too low to really carry away an astronaut. Mars has an atmosphere that’s only about one percent the density of Earth’s atmosphere, and it’s mostly composed of Carbon Dioxide while Earth has an atmosphere rich in Nitrogen and Oxygen thanks to LIFE and PLATE TECTONICS.

The rest of the crew head back towards Earth thinking their friend and fellow astronaut, Mark Watney, is deceased on Mars as his suit bio-monitor indicated his space suit was broken.

Mark, however, survived the injury and made it back to their temporary Mars Habitat (“HAB”) where he patches his injury and begins to plan on how to survive for four years alone on Mars - four years is the time another mission is due to reach the Red Planet - with only about a year’s worth of food.

Some classic story-telling techniques are used including having the protagonist - Watney - “narrate” through a video journal. Also, the first act of the story sees the hero go from a “normal” situation to one where his or her very survival is challenged. The rising action of the first act shows the protagonist meet these challenges and battle back. But, as we know, the mid-point of a story will see our hero faced with a major setback.

Watney used human waste, added to Martian dirt, to make a kind of soil in which to grow potatoes to help sustain him. We saw, earlier this year, in “The Biggest Little Farm” how plants need soil to grow - which is a living ecosystem with microorganisms. Dirt is, essentially, minerals and rocks.

Also, there are several scenes showing the actor playing Watney - Matt Damon - looking muscular and healthy at the beginning of the story. This is to show his physical deterioration when he’s forced to go on a low-protein diet. This will be especially important when we study the main organic molecules in life - Nucleic Acids (DNA / RNA), lipids, carbohydrates, and proteins.

While this part of the story stretches what is possible, it does highlight the fact that Martian dirt is not able to support life, even with the addition of human waste as fertilizer.

Watney uses a catalyst - something that helps a chemical reaction take place - to break down rocket fuel and react the hydrogen gas with oxygen to make water. Recall water is two atoms of hydrogen covalently bonded to one atom of oxygen.

Water, needed for the potatoes crops and for drinking - in this movie - is the most important compound for life and critical for sustaining the chemical reactions needed for life. Also, it’s again shown repeatedly that Earth has abundant water on the surface while Mars is both cold and dry.

We studied atomic structure and in the documentary “Twisting the Dragon’s Tail” we saw how some elements are radioactive, meaning they transmute - break down - into completely different elements. Almost one hundred years ago humans used Plutonium and Uranium to build weapons that destroyed two populated cities in Japan. Post World War II we’ve used radioactive elements for energy production, medicine, geologic dating, and many other technologies.

In “The Martian” - and space travel in general - we use radioactive isotopes to explore space by using it for long-lasting power sources. Watney digs up a discarded nuclear battery to use as a heat source, as it is no longer useful as a power source but still releases heat. This is important as Mars’ thin atmosphere holds in very little heat whereas Earth has a greenhouse effect that effective keeps our plant at a habitable temperature.

Questions to think about for the second half of the story:

Taking into account Newton’s Laws - why - when Watney’s crew mates (friends) learned he was alive - did they not, simply, “Turn around” their spaceship and go back to pick him up?
Why does it take twenty minutes, or more, for a radio signal to traverse the distance between Earth and Mars?
Why does The Hermes, the spaceship carrying the astronauts between Earth and Mars, have several sections that spin?
Why does Watney have to grow the potatoes in the HAB? Why not just plant them outside in the Martian dirt after adding fertilizer?