I am trying to understand why altcoings are fall. Is there any way to see altcoin prices independent from Bitcoin?
No, altcoins are dependent to bitcoin so there's always a domino effect when the price of bitcoin starts to be shaken out, altcoins will follow as well.
If demands are get higher for an altcoin while Bitcoin falls, do you think altcoin will get more value. I am newbie and trying to understand.
Yes, altcoins will get more value if there is a big demand but don't expect that it will stay for a long time. Traders will always be traders, they won't stay on a single coin unless they are just a holder. When that altcoin gets a big demand, they will simply sell that coin and buy back with bitcoin.