The American Biology Teacher
By Arthur Louis Odom
“Secondary and College Biology Students’ Misconceptions about Diffusion & Osmosis”
Publisher:
Vol. 57, No. 7
Pp. 409-415
1995
Secondary and College Biology Students’ Misconceptions about Diffusion & Osmosis
Type: Empirical
Data collection method: Test
Number of subjects, range: Large — 31 or more
Grade and age of subjects: Adult — over 18 years
- All particles are in constant motion.
- Diffusion involves the movement of particles.
- Diffusion results from the random motion and/or collisions of particles (ions or molecules).
- Diffusion is the net movement of particles as a result of a concentration gradient.
- Concentration gradient is a difference in concentration of a substance across a space.
- Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
- Diffusion continues until the particles become uniformly distributed in the medium in which they are dissolved.
- Concentration is the number of particles per unit volume.
- Temperature increases motion and/or particle collisions.
- Diffusion rate increases as the concentration gradient increases.
- Diffusion rate increases as temperature increases.
- Increased concentration increases particle collisions.
- Diffusion occurs in living and nonliving systems.
- Osmosis is the diffusion of water across a semipermeable membrane.
- Tonicity refers to the relative concentration of particles on either side of a semipermeable membrane.
- A hypotonic solution has fewer dissolved particles relative to the other side of the membrane.
- A hypertonic solution has more dissolved particles relative to the other side of the membrane.
- An isotonic solution has an equal number of dissolved particles on both sides of the membrane.
- Osmosis is the net movement of water (solvent) across a semipermeable membrane from a hypotonic solution to a hypertonic solution.
- Osmosis occurs in living and nonliving systems.
- A semipermeable membrane is a membrane that selectively allows the movement of some substances across the membrane while blocking the movement of others.
- Cell membranes are semipermeable.