Which of the following concepts is not an evidence of the particles nature of matter?

Analysis

The question asks us to identify which of the listed phenomena is not evidence of the particulate nature of matter. To answer this, we need to understand what "particulate nature of matter" means and which physical or chemical processes demonstrate that matter is made of tiny, moving particles.

Concept Explanation

The kinetic theory of matter states that all matter is made up of tiny particles that are in constant motion. Evidence for this theory includes:

1. Brownian Motion: The random, zigzag movement of microscopic particles suspended in a fluid (liquid or gas). This is caused by the collision of invisible, fast-moving fluid molecules with the visible particles.
2. Diffusion: The net movement of particles from a region of higher concentration to a region of lower concentration. This proves that particles are in constant random motion and can move through spaces between other particles.
3. Osmosis: A special case of diffusion involving the movement of solvent molecules through a semi-permeable membrane.
4. Esterification: This is a chemical reaction between an alcohol and an organic acid to form an ester and water. While it involves molecules, it is a chemical reaction (a process of bond breaking and bond formation), not a physical phenomenon used as evidence for the kinetic theory of matter.

Wait, let's look at the options again:

• Diffusion (A): Evidence of particle motion.
• Brownian motion (B): Direct evidence of particle existence and motion.
• Diffraction (C): This is a property of waves. Diffraction occurs when a wave encounters an obstacle or a slit that is comparable in size to its wavelength. It is a fundamental characteristic of wave motion, not a proof that matter is made of particles.
• Esterification (D): While chemical, it involves the interaction of molecules.

However, in the context of physics examinations like JAMB, Diffraction is the classic "odd one out" because it is a phenomenon exclusively associated with wave behavior, whereas the others (Diffusion, Brownian motion) are standard proofs for the particle theory.

Step-by-Step Solution

1. Evaluate A (Diffusion): Diffusion occurs because particles are in constant motion. This is evidence of the particle nature of matter.
2. Evaluate B (Brownian motion): This is the most famous evidence for the kinetic theory of matter, confirming that particles exist and are constantly moving.
3. Evaluate C (Diffraction): Diffraction is the bending of waves around corners or through apertures. It is a defining characteristic of waves, not particles. Therefore, it does not provide evidence for the particle nature of matter.
4. Evaluate D (Esterification): Although this is a chemical process, it involves the rearrangement of atoms and molecules, which inherently assumes the existence of particles.

Comparing these, Diffraction is the most distinct "non-particle" concept here.

Conclusion

Diffraction is a wave phenomenon, whereas the other options relate to the behavior of particles.

Exam Tip

Whenever you see a question about "evidence of the particulate nature of matter," look for keywords like motion, collision, or mixing. If you see terms like diffraction, interference, or polarization, those are almost always related to wave properties, not particle properties!