Answer:
Osmosis
Step-by-step explanation:
The phenomenon you're describing is known as osmosis, a fundamental process in biology and chemistry. Osmosis is the movement of solvent molecules (usually water) across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. In this case, the partially permeable membrane of the bag separates two solutions with different sugar concentrations.
Let's break down what's happening in your experiment:
A bag made from a partially permeable membrane is filled with a strong sugar solution: This bag is typically made of a material that allows water to pass through but not the sugar molecules. The strong sugar solution inside the bag means it has a high concentration of solute (sugar).
The bag is tied to a piece of glass tubing and then put in a beaker of a weak sugar solution: The beaker contains a solution with a lower sugar concentration compared to the strong sugar solution inside the bag.
Now, here's why the liquid rises up the tubing:
Osmosis causes water molecules to move from an area of low solute concentration (the weak sugar solution in the beaker) to an area of high solute concentration (inside the bag with the strong sugar solution). Water molecules move through the partially permeable membrane to equalize the solute concentration on both sides of the membrane.
As water molecules move into the bag, it dilutes the strong sugar solution inside the bag, reducing its sugar concentration.
This dilution inside the bag creates a concentration gradient between the bag's interior and the beaker. Water continues to flow into the bag to equalize the sugar concentration between the two sides.
As more water enters the bag, the volume of the solution inside the bag increases. This increase in volume creates pressure inside the bag.
The pressure inside the bag forces the liquid to rise up the glass tubing. This rise in liquid level in the tubing is a visible indicator of osmosis occurring.
In summary, the liquid rises up the tubing in this experiment because of the osmotic movement of water from the weaker sugar solution into the bag with the stronger sugar solution, creating a pressure difference that forces the liquid up the tube. Osmosis seeks to balance solute concentrations, and in this case, it results in the flow of water into the bag.