In this classification question on basic science terms, find the odd word from the group: Fire, Light, Gas, Water.

Introduction / Context:
This reasoning question asks you to pick the odd word out from a set of basic science related terms: Fire, Light, Gas and Water. Although all four words are common in everyday life, they belong to different physical categories. Correctly recognizing which one does not fit with the others is the key to solving the problem.

Given Data / Assumptions:

• Words given: Fire, Light, Gas, Water.
• We consider their nature in terms of matter and energy.
• Three of these can be treated as forms or states of matter.
• One is best described primarily as a form of energy rather than as matter.

Concept / Approach:
In basic science, most physical objects and substances are categorized as matter if they have mass and occupy space. Energy, on the other hand, is the capacity to do work or cause change and does not have mass or volume in the same way. Water is a liquid, Gas refers to a state of matter, and Fire is a physical phenomenon that involves hot gases and burning material. Light, however, is electromagnetic radiation and is primarily considered as energy, not material substance. This distinction guides us to the correct answer.

Step-by-Step Solution:
Step 1: Analyze Water.Water is a liquid form of matter with definite volume and variable shape. It clearly has mass and occupies space.Step 2: Analyze Gas.Gas is a physical state of matter in which molecules are far apart and move freely. Gases also have mass and occupy space.Step 3: Analyze Fire.Fire is a visible effect of the process of combustion. It involves hot gases, ionized particles and burning material. Although it also releases energy, it is closely associated with physical matter in the form of fuel and hot gases.Step 4: Analyze Light.Light is electromagnetic radiation that can travel through a vacuum. It has no mass in the classical sense and is best treated as a form of energy rather than as matter.Step 5: Compare the four terms.Water, Gas and the material aspect of Fire all involve matter, whereas Light is purely energy.

Verification / Alternative check:
Another way to verify the answer is to ask which of the four can be stored in a container as a substance. Water can be stored in a bottle, Gas can be stored in a cylinder, and Fire involves physical burning gases and fuel in a confined space. Light, however, cannot be stored in a container as a substance; it can only be produced, reflected or absorbed. This clearly separates Light from the other three options.

Why Other Options Are Wrong:
Fire: Although it emits energy, it is the result of combustion of matter and is strongly tied to physical substances.
Gas: A definite physical state of matter, so it fits with Water and the material aspect of Fire.
Water: A common liquid state of matter, clearly not the odd one out when compared with Gas and Fire.

Common Pitfalls:
Some students may initially think Fire is the odd one because it looks more dramatic or dangerous. Others may confuse Gas as an abstract idea like Light. However, in physics terms, the major conceptual divide is between matter and energy. Keeping that in mind helps you identify Light as the unique term in this group. Always think in terms of basic definitions from science when answering such classification questions.

Final Answer:
The odd word out is Light, because it is primarily a form of energy, while Fire, Gas and Water are associated with material substances or states of matter.