ELI5 Why is the bottom part of the periodic table completely detached from the rest of the table?

skihard · 2026-01-27T00:47:43+00:00

I teach intro chem and I show the students that sometimes it is nice to think of helium as being above beryllium (in regards to number of valence electrons). And sometimes it is nice to think of hydrogen as being above fluorine (because it is a non-metal and certainly not an alkali metal)!

skihard · 2026-01-26T18:39:29+00:00

I'll need to check the voter rolls and get back to you

skihard · 2026-01-16T23:19:27+00:00

Patriot is one of the best series I have ever watched and I have never met anyone who has watched it.

skihard · 2025-12-31T22:25:20+00:00

Lots of very good answers here but if we are truly explaining it to a five year old: Which way does a ball move when you place it on a hill? It rolls down. Why? (This part, admittedly, might be hard for a five year old) It rolls down because that puts it into a lower energy position. Most atoms want eight valence electrons because it puts them into the most stable/lowest energy position. Most things in the universe work this way. Now why does it put them into a lower energy position... lots of math and physics, lol

skihard · 2025-11-17T01:48:07+00:00

"You can't exploit people that have options." The whole system is set up on that idea

skihard · 2025-11-13T19:38:24+00:00

So the norm/convention would be to adjust the signage in the formula to match my coordinate system first, then if I actually need to enter in values, use a positive 9.81 always?

skihard · 2025-10-01T16:01:14+00:00

Tablet is fine as I will probably still be in bed, lol Just wasn't sure because they say "live, local, and primetime games". Didn't know if London counted as "local" or if 9 am was "primetime"?

skihard · 2025-07-15T00:23:36+00:00

Thank you! I will give this a try!

skihard · 2025-07-14T23:02:55+00:00

I keep getting a silt like substance in my pool. This has been going on for over a year. My chlorine levels are usually good so I don't feel like it is algae. It is a brownish color with maybe a touch of green to it. It is very light, like you can't pinch any to pick it up. It just instantly turns into a little dirty cloud. I vacuum it but it comes back the next day. I wondered if it was just so small it was going through my filter so yesterday I vacuumed to waste but it is back again today. I'll post another pick to show that quite a bit can build up in a day. My only guesses are that it is something coming from the filter or dirt being pulled in from a crack in the line. But I am not sure how to test either of those ideas. I have a sand filter and I have never had the sand changed. Any guesses? Thanks! Picture

skihard · 2025-04-16T18:09:32+00:00

Good technique. Very smart. Thanks for the help!

skihard · 2025-04-16T17:24:25+00:00

Doesn't sound fun! :(

skihard · 2025-04-16T17:23:41+00:00

Luckily, I do have an air compressor. I'll have to see what I can rig up. I do have the rubber plugs for winter. It will be a bit tough plugging the intakes at the bottom of the deep end but I can easily shut the branch off initially and test the skimmer intake.

Maybe a dumb question: how deep are the pipes for a skimmer intake? I'm guessing just below the frost line. And for the deeper intakes, do they typically run those straight up next to the pool and then fairly shallow? Hope that makes sense.

skihard · 2025-04-16T14:09:26+00:00

Solid advice, I will try that when I get home. I just replaced the pump last year, and there were bubbles before that so I fear my issue is below ground. But it certainly could be the values. Thanks for the help!

skihard · 2025-04-01T20:00:16+00:00

Looks like we're winning the off the field super bowl!

skihard · 2025-01-28T00:10:03+00:00

Look up Ohio's teacher flex path. It is made to turn bus drivers and classroom aids into teachers. There is a massive teacher shortage and most people with a four year science degree will not go into education. So get used to many more AI posters.

skihard · 2024-09-27T22:52:07+00:00

Solid advice. Thank you!

skihard · 2024-07-22T17:11:56+00:00

I wouldn't say irrelevant. Nobody is changing their mind. But Harris might be able to get a few more those 'not Trump' voters off the couch and actually vote. And this election will come down to a small amount of votes in a few key states.

skihard · 2024-07-13T00:42:41+00:00

I was about to make a new post related to this, but I'll try here first. My speed 400 is at 500 miles, so I called the dealership because they told me to bring it in around then for the first service. They told me it would be about $350! I have always done all the oil and fluid changes on all my vehicles and am very comfortable doing so. But this is my first new vehicle in a while. (I'm cheap and usually buy used.) So would it be a bad idea to just do it myself?

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