Required Practicals - Investigating Osmosis Flashcards
What is osmosis?
the movement of water from an area with a high concentration of water to an area of low concentration.
What is a solute?
something that dissolves in water
What is the point of the practical?
To find out what happens to cells when you put them in different concentrations of sugar or salt solutions. (how water moves in and out of the plant tissue).
What is the independent variable (Deliberately changed)?
The concentration of sugar/salt solution
What is the dependent variable (one that is measured)?
the change in potato mass
What are the controlled variables (kept the same)?
temperature, the volume of solution and length of time that the potatoes are left in the solution
What are the hazards?
care must be taken when cutting the cylinders of potatoes
Method:
- cut potato + measure mass
- place potato in different concentrations of salt/sugar solutions
- remove after 30 minutes and measure
What shows that a change has taken place?
A change in mass
Why does it need to be rolled in tissue after before final measurement?
To remove excess solution and get a more accurate reading
If potato gets bigger, what does this mean?
There is a low concentration of salt/sugar in the concentration.
If the potato gets smaller, what does this mean?
There is a high concentration.
What does no change in size, what does this show?
That the concentration inside the potato is the same as in the solution.
