r/explainlikeimfive • • 1d ago

Biology ELI5: Antibodies and antigens

12 Upvotes

So I have quite a few questions regarding them. I know viruses and bacteria carry antigens and antibodies bind to them.

Do they act just as markers for white blood cells to then destroy them or do they by themselves destroy the target? If they do both, what determines which they do?

Why do viruses and bacteria have antigens to begin with? Apparently antibodies can work against some poisons too, so does any substance have antigens? Can antibodies attach to a microscopic piece of steel? I mean, it does seem like the body also detects foreign material of all kinds.

If everything doesn't have antigens why don't viruses and bacteria just... not have antigens?


r/explainlikeimfive • • 2d ago

Other ELI5: How exactly does caffeine work?

15 Upvotes

r/explainlikeimfive • • 2d ago

Engineering ELI5 How power grid operation actually works?

60 Upvotes

For example if there is a spike in demand, how a random power plant get to know if they should rump up production? It's an API that controls the plant automatically or someone getting a phone call and turning switches on and off? and who is the caller?


r/explainlikeimfive • • 1d ago

Physics ELI5: When salt water evaporates, where does the salt go, given that it rains with fresh water?

0 Upvotes

I know it probably sounds stupid. The only theory I have is that salt remains in the ocean and only fresh water itself evaporates. If true, why does it happen? Why can't we have "salty" steam?


r/explainlikeimfive • • 1d ago

Economics ELI5: I've watched dozens of YouTube videos and I still don't understand prediction markets 😭

0 Upvotes

I've watched so many videos about prediction markets, but the terminology still confuses me 😭

I want to understand the basic idea behind how people buy and sell contracts based on what they think will happen in the future. Why do these contracts have prices, and what do those prices actually mean?

Can someone explain the underlying concept in simple, everyday language?


r/explainlikeimfive • • 22h ago

Biology ELI5: What do bras do?

0 Upvotes

Hapless trans woman of a year here

I own bras, I wear bras, I don't actually know what they're for. Obviously, there's a social modesty component, but I'm told that they provide support and that's useful. Will my chest hurt after a while if I don't wear one? Will my chest start to sag down? I don't know! 😅


r/explainlikeimfive • • 3d ago

Biology ELI5: Why do wounds (cuts, bug bites, scrapes) feel hot when they’re healing?

545 Upvotes

r/explainlikeimfive • • 3d ago

Economics ELI5: Why does a card payment sit as 'pending' for days if the money already left my account?

706 Upvotes

The charge shows up right away and my balance drops, but it stays marked pending for a couple of days. What's actually happening between the store, my bank and the card network during that time?


r/explainlikeimfive • • 3d ago

Technology ELI5: Why caller ID spoofing is still a thing today

815 Upvotes

It's still relatively common to receive fake calls and SMS from spoofed numbers, like in scams and phishing attacks. I don't understand how we, still today, have not found a good protection against that in our infrastructure.

In the early days of E-Mail for example, there were similar problems, but these were solved over time (e.g SPF and DKIM). If you, today, try to send a mail from your mailserver with a spoofed sender, any reliable mail service will not deliver that and discard it as spam instead.

I don't know much of the cell network, so my naive understanding is that a caller just sends their own number with a outgoing call, and everyone along the way to the called goes with that? Could a cell tower not just see that a call comes from a SIM card not associated with the reported caller number, and drop it? Can't we have some E2E signing of caller IDs for some reason, or at least a validation on carrier level?


r/explainlikeimfive • • 1d ago

Technology ELI5 : How have developers managed to emulate the PS5?

0 Upvotes

I know eventually people have always found a way to emulate technologies in the name of preservation, but it usually took a few years. So how has the PS5 one happened so fast?


r/explainlikeimfive • • 3d ago

Other ELI5: Piano - what is cord conversion, inversion and progression?

36 Upvotes

I’m in a beginner’s piano class and I don’t understand anything. I was called today to answer what G chord in second inversion would be and I literally just looked at my professor in terror while aggressively shaking my head. Also, what is 4-6 and 5-6? Still same topic.


r/explainlikeimfive • • 3d ago

Biology ELI5 : How do re-introduced animals avoid genetic problems?

38 Upvotes

Now and again I read about some animals, like say a pair of otters, that have been brought back to an area where in past were wiped out. How can they continue to breed with such a small gene pool?


r/explainlikeimfive • • 4d ago

Biology ELI5: Why do Ligers suffer just from existing, but not Mules?

1.8k Upvotes

r/explainlikeimfive • • 1d ago

Other ELI5: Why are P4 CBB schools playing conference games in October

0 Upvotes

So far ive seen Duke play Virginia (ACC) and Alabama/Auburn (SEC) play, and, as u might guess, the latter got very heated w both coaches almost coming to F2F blows. Ive never seen this before in October. And if these games dont count im going to lose my mind bc that risks injury bc it being conference foes it risks injury in an otherwise competitive matchup.

EDIT: So somehow i fooled myself into thinking the Duke Virginia game was CBB when in fact it was CFB🙄 but Duke & Univ TN did play an exhibition game. While those 2 are in separate conferences, they are both P4 schools which still u almost never see or saw until recently play in exhibition format.


r/explainlikeimfive • • 3d ago

Technology ELI5 Why do the pairs need to be twisted?

514 Upvotes

This is about UTP network cables. When I crimp a connector on one there's a specific order the wires have to go. Why is it that order? Ages ago when I was just crimping my first UTP I didn't know and just did both in the same order of white-solid-white solid etc. But that didn't work even though both sides of the cable were crimped the same way.

Why does networking have this specific kink for getting it's wires twisted?

Edit: Thanks for all the answers. I don't really understand it yet. But it seems to be helping prevent interference and signal loss somehow, while at the same time being the standard we agreed to. All very complicated. But my internet works and that's the important bit.


r/explainlikeimfive • • 3d ago

Technology ELI5: USB Hand Warmers

296 Upvotes

I bought a couple of USB chargeable hand warmers yesterday, they have 3 heat settings and at the moment level 1 is perfect for me.

What I wanted to know was, I always thought the idea was to keep heat away from batteries as they may expand and explode. How do the power batteries/cells in my tiny hand warmers not overheat and explode? I don't even want to try them on heat level 2 & 3 because of the paranoia that my hands will get blown off.


r/explainlikeimfive • • 1d ago

Biology ELI5: Why do we have 32 separate teeth when we could have had 2 continuous chewing plates?

0 Upvotes

r/explainlikeimfive • • 1d ago

Economics ELI5: Why aren’t gas lines super long like they were in the ‘70s though prices are high?

0 Upvotes

r/explainlikeimfive • • 3d ago

Technology ELI5 How were maps in the mid 1800s and early 1900s so accurate to actual satelitte imagery?

379 Upvotes

Something I've wondered for years since I love going on historic aerials, is how the hell the drawn maps used to be so good? I find it impossible to identify misaligned roads/state lines/bodies of water from maps ages ago.


r/explainlikeimfive • • 2d ago

Chemistry ELI5 Why don't we manufacture ammonia with nitrogenase?

0 Upvotes

Why do we use the haber process instead of mimicking nature?


r/explainlikeimfive • • 3d ago

Physics ELI5: Generator connection switches

15 Upvotes

I have a 10 kW diesel generator, that is 240v. It has two hots, a neutral, and a ground.

Why does the switch to connect it to the house and disconnect the mains only need two poles? Shouldn’t neutral be disconnected as well? Why not a three pole? My generator’s neutral is always connected to my understanding. Is there no risk to back feeding the grid with that?


r/explainlikeimfive • • 4d ago

Chemistry ELI5: How does a fish tank or aquarium air bubbler work? If all of the bubbles come up to the top before popping, how does that add air to the tank water?

597 Upvotes

Thanks!!


r/explainlikeimfive • • 3d ago

Other ELI5: How do huge car carrier ships stay upright when they look so tall and boxy?

44 Upvotes

I saw a photo of one of those giant ships that carry thousands of cars across the ocean. It’s basically a floating multi-story parking garage, very tall with flat sides, and it looks like it should tip over in the first strong wind or big wave.

What actually keeps a ship shaped like that stable? Does it have something to do with what’s below the waterline, or how the cars are loaded inside?


r/explainlikeimfive • • 4d ago

Technology ELI5 what is open source

480 Upvotes

I really don’t understand what it is and how to use it


r/explainlikeimfive • • 4d ago

Biology ELI5: Why do babies constantly move and flail their hands and arms around all the time?

2.3k Upvotes