Ask Mr. Science
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Life in the seas

There were a number of related questions on this, so I pulled together some images and videos about sea life. I went from the shore (tide pools, sandy beaches, further offshore, all the way to the deepest parts of the ocean bottom.




Nov 2017

 

Paper rockets

I saw this at the 2016 Bay Area Maker Faire, and it was an obvious success with the younger crowd. Since I started doing a monthly 'Science Saturday' at the Santa Fe Children's Museum, which caters to young children, it was an obvious thing to do. Full credit goes to AirRocketWorks for the inspiration and their standard template. Here is my slightly modified template.

On the right I have

  1. A bicycle pump with a pressure gauge
  2. I 2-liter bottle serves as a compressed air tank
  3. The big red launch button
  4. The launch tube
  5. I keep one template taped to a board
  6. This one has hit the ceiling too often
  7. On the next picture: construction tubes
The hardware is 3/4" (OD) PVC tube, hoses are 1/4", some plywood and paint. The big red button is a pneumatic valve from Zoro, G2731924 manual air control valve. I removed the latch so it returns to the closed position itself.

The rockets are made from a single standard sheet of paper, with the parts and instructions printed on them. All you need is scissors and masking tape. The rocket tube is wrapped around the construction tube, and the fins and nosecone are cut out and taped on. When the rocket is finished, it is slipped off the construction tube and onto the launcher.

On the construction tubes, I put a strip of tape down the length. This way, if the rocket is made really tight, it may be hard to get off the construction tube, but will fit a bit looser on the launch tube.

At the Children's Museum, there also are colored feathers, ribbons and the like to decorate the rockets. [and for reference, in 2+ hours, 23 rockets were made.]


November 2017

 

Ocean acidification

Since we had talked about global warming earlier, as well as sea life, I did an hour on ocean acidification. In order to introduce the concepts of acids and bases, I brought enough stuff to do the red cabbage acidity indicator demo.

By the way, I had brought this image to illustrate the pH scale, since it showed the colors of the cabbage juice. After a while I realized that this picture dated back to the the days of acid rain. The acid rain problem echoed, on a smaller scale, the ocean acidification problem: fossil fuel burning causing sulfuric acid to rain down and kill lakes, streams and forests. The area affected was not global, though it spanned the US Northeast and Canada, as well as Scandinavia. The solution was regulation to scrub sulfur compounds from smokestacks. This happened after much opposition from the polluters, and now few people remember the days of dead lakes, streams and forests. The other nice thing about this problem was that solution worked fast: it takes only a few rainstorms to clean the air of sulphur compounds, and the ecosystems recovered in a few decades. No such luck with CO2 pollution: CO2 stays in the air for many centuries, and the oceans will take millennia to recover.

Bring:
  • Red cabbage
  • Cutting board and knife
  • Water kettle, water bottle
  • Blender
  • Sieve, spoon
  • 3 or more glasses
  • Lemon juice, ammonia, soda
  • ...



November 2017

 

plastic
Plastic

Initially, plastics were invented to replace scarce and expensive natural products.

1869 - Celluloid 
The first synthetic polymer was invented in 1869 by John Wesley Hyatt, who was inspired by a New York firm's offer of $10,000 for anyone who could provide a substitute for ivory. The growing popularity of billiards had put a strain on the supply of natural ivory, obtained through the slaughter of wild elephants. By treating cellulose, derived from cotton fiber, with camphor, Hyatt discovered a plastic - celluloid.

1907 - Bakelite 
The world's first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term 'plastics'. Formed from a condensation reaction of phenol C6H5OH with formaldehyde (CH2O). It was intended as a substutute for shellac (a resin made by lac bugs in Thailand, ~100000/kg). Used to make records until 1950.
Thermoset, "The Material of A Thousand Uses".

1913 - PVC
polymerization of gas in sunlight. Replacement of natural rubber rubber. (reaction first seen in 1838 and 1872)

1933 - Polyethylene
(war secret, radar app)

1940 - Nylon
Invented by Wallace Carothers in 1935 as a substitute for silk, was used during the war for parachutes, ropes, body armor, helmet liners, and more.

1940 - Plexiglas
Provided an alternative to glass for aircraft windows.

1941 - Styrofoam

1941 - PET polyethylene terephtalate #1 recyclable

1941 - Teflon
polytetrafluoroethylene (PTFE)

Etc., etc. ----------------

half of all plastic is single-use

shopping bag 20 years, foam plastic cup 50 years, plastic bottle 400 years, diaper 450 years, fishing line 600 years.

2018







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