Liquid is a payment channel, not a pegged sidechain. They are completely different things. Do you not understand how Bitcoin works?
I thought Lightning was the payment channel.
3 years resident, 2 years intern.
No, I'm not even a real doctor.
OK Frap.doc Junior, where's the citation for your outrageous/libelous "billionaire bribed Gmax to cripple Bitcon" claim? No rush, we'll wait.
...
...
Anyway, Lightning is one possible implementation for the general idea of a payment channel. It's like how there's more than one kind of band-aid, but there is the well-known official Band-Aid too (and they come in different shapes/sizes/fun designs/prices/materials).
If you don't know what write caches are and why it's a Very Good Thing for your CPU, hard drive, OS, and torrent client to each have one, you'll never understand, much less like, payment channels such as Lightning. Sorry about that.
As for side chains, you may be able to think of them like cities or counties within a state. They can set their own local laws as they like, as long as they do not conflict with the nation they are part of. Your Bitcoins have to obey the local laws while they are visiting a sidechain, but can leave if they don't like it.
Good luck in school. I recommend doing eye care; it seems cushy. A few minutes zapping with the Lazik, a few minutes chatting up the customers, and then you can spend the rest of the day posting about how much you love buying Frappucinos with Bitcoin discounts, and how Bitcoin will surely choke to death if tx fees at Starbucks ever went above 10 cents.