Quote Originally Posted by sang56 View Post
I said "chắc là" to alert the questioner to check his source because it’s unusual for textbooks (where the sentence must have come from) to make such a such a spelling mistake (farher for farther). If not, then "farther up" or at least “farther” is such a common word that the questioner should have found it in a dictionary.

"farther up" = lên cao hơn, as you pointed out, is the more precise translation. The physical situation here, however, may be as follows:

Due to the osmotic pressure difference, water (liquid in the sentence is very likely water) is being "sucked" from one side of a semi-permeable membrane to the other side. This increase in the amount of water on that side causes the water level to rise inside a tube connected to it.

The potential complication of saying "farther up = lên cao hơn” is cao hơn compared to what? The correct understanding is that the new water level is cao hơn what the water level was before water is being transported through the membrane. I was concerned that the more precise translation may cause unnecessay confusion about the physical phenomenon. And since “đẩy cao lên” already implies the new level would be higher than before, which would adequately address the questioner’s lack of understanding of the sentence, I left the word “hơn” out.
Of course, that was an excellent explanation. I defer to your expertise in this matter. That's why I stated that this was right up your alley.