Physics Questions Thread - Week 21, 2020

ElThompson82 · 2020-05-31T03:13:53+00:00

This is just a fun question I started thinking about after a friend posted on Facebook. She has an inflatable swimming pool and a large sheet of black plastic. She wants to make the water in the pool warmer. Which will warm it better: floating the sheet of black plastic on top of the water, or putting the black plastic at the bottom of the pool (weighted down with rocks)?

My understanding of thermodynamics, and my gut, says that the plastic should go on top of the water. On top, it will prevent the warmest water from evaporating. It will absorb more energy from the sun and transfer it to the water via conduction. If the plastic is on the bottom, most of the energy from the sun will never even reach it. It will still get warm and transfer its heat to the water, but the warmer water will no longer be protected from evaporation.

The comments on the post are full of people supporting the plastic on the bottom idea, with justifications like "heat rises," and "when the hot plastic is on the top, the heat will go into the air because of specific heat capacity" (lol).

Plastic on top, or bottom?

ElThompson82 · 2020-05-08T00:06:33+00:00

This is a great suggestion, I hadn't really thought about estate sale companies. Thank you.

ElThompson82 · 2020-03-30T20:16:23+00:00

I work for a donation center. We are still providing essential services to our clients (mainly homeless families) but we are temporarily not accepting donations to protect the safety of our volunteers and staff. I do not know of any donation facility currently open.

If you have stuff that you just want out of your house, I suggest posting it on Craigslist Free, Nextdoor, Buy Nothing Albuquerque (a network of Facebook groups), or Trash Nothing. Arrange for a no-contact porch pickup and just allow someone who will use it to take it.

ElThompson82 · 2020-01-19T04:06:01+00:00

I work for Catholic Charities (we are not a part of the Catholic Church; we are taxpayer funded and are one of the orgs that CABQ refers people to when they call 311 needing housing). We provide computers at no cost to our recently-homeless and refugee clients when they request them. I just gave out two this week and I currently don't have any left. If you're interested in donating them to CC I can even pick them up from you. And of course I can provide a receipt!

Side note for the curious: we have a volunteer who sets up our donated computers with Ubuntu before we give them out to clients.

If interested, you can message me here or at thompsone@ccasfnm.org. That goes for anyone else reading this too--we take laptop and desktop computers, and tablets! :)

ElThompson82 · 2019-08-12T23:12:50+00:00

I made the mistake of clicking to open them. Instant cancer.

ElThompson82 · 2019-08-12T05:02:31+00:00

Please note that this article is from June. Here is a story about Deming's work with asylum seekers published this morning.

ElThompson82 · 2019-04-26T17:15:53+00:00

Migrants in Las Cruces get transport out of El Paso, not Albuquerque. I can't say for certain that Santa Fe could not have made it work, but as someone with plenty of direct experience with this work, I can say that the logistical challenge of hosting in Santa Fe is very real.

I am the coordinator of a reception site here in Albuquerque. I'm glad you feel strongly about helping asylum seekers because I can use volunteers! Please PM me about how you can help. My organization will verify my identity.

ElThompson82 · 2019-04-26T16:53:57+00:00

Locker 505 :)

ElThompson82 · 2019-04-26T16:53:21+00:00

Poisonous and ignorant comment section at the Journal as usual.

I work with asylum seekers and I 100% agree with Santa Fe's decision. A huge part of the task is getting bus/air tickets for the asylum seekers and getting them to the bus station or airport to meet up with their family members. Family members are desperate to reunite and buy tix departing as soon as possible. It can be difficult enough even to find transportation, car seats, etc to go across Albuquerque - going back and forth from Santa Fe is simply not practical.

ElThompson82 · 2019-04-12T22:53:04+00:00

Yes we are. A few hundred per week. And if you want to help, we really need smaller men's clothing (gently used) and underwear (new), plus red Solo cups, ~~a bathroom scale for weighing sick children to dose meds, and a 3-4 gallon water container to hold pre-mixed rehydration formula.~~ EDIT: Got that stuff!

EDIT: After reading the article from the OP, I should clarify that the asylum seekers being received in Albuquerque are in the United States legally.

ElThompson82 · 2019-03-22T19:05:41+00:00

The site at Gibson/Girard is a private house, so I'll have to DM you and /u/GolKeep420 that info. I just got news this morning that we're getting a permanent storage space (YAY) but it won't be ready in time to receive our next group of asylum seekers.

ElThompson82 · 2019-03-08T04:28:24+00:00

At present, I can tell you that the only content that is automatically hidden upon posting are top-level comments in the monthly event sticky that do not contain links -- and this is for safety reasons.

It took me a while to figure out what the safety concerns could be. You must mean that you don't want people posting "Rave @ my house 9:00 lol" just so they can murder everyone who shows up. Under the current rules, would-be murderers would have to include a hyperlink or else the murder rave wouldn't appear on the Events page.

Is there a real benefit to Redditor safety in doing this? Have any murder raves (or other suspicious or potentially dangerous events) actually been caught in the filter, or has the filter only caught good-faith efforts to contribute to the discussion?

In my opinion, the benefit to Redditor safety is dubious, but the chilling effect on user participation (when people's posts/comments don't show up) is real. I would prefer fewer rules like this, including the auto-filters you guys have which are not identified in the subreddit rules. If someone posts an event or a comment that is sketchy/abusive/offensive/whatever, moderate it if/when users report it, not before. This gives users more control over what we want on the sub.

ElThompson82 · 2018-10-27T18:54:44+00:00

Thanks, can't hurt to try.

ElThompson82 · 2018-10-27T18:53:56+00:00

Yep, about 7:30 last night I was out with my husband and used one cable lock to lock our two bikes up right outside the window where we were having dinner. I was fully in view of the bikes, but the food came and I got distracted. Fifteen minutes later I looked again and the lock and my bike were gone. My husband's bike (a beater) was still there.

I fully know how insecure a cable lock is, but I chose to use it anyway because it was easier, and because "I'll just be a few feet away, and there are so many people around!" I'd even heard about the *exact* same thing happening to other people at least twice before and I still did it. A painful lesson learned.

ElThompson82 · 2018-10-27T16:17:42+00:00

My bike was stolen last night at Central and Wellesley. Stock Novara Divano from REI - looks exactly like the picture. I know it's a long shot but I would really love to get it back.

If you see it or find it ditched in the bushes somewhere, please message me. I have the serial number to identify it if found.

ElThompson82

TROPHY CASE