A substance used to bring down the temperature of a burning wooden log below its ignition temperature _____.

Options

A. Water
B. Oil
C. Kerosene
D. Carbon dioxide

Answer

To solve the question "A substance used to bring down the temperature of a burning wooden log below its ignition temperature _____," we can follow these steps:

### Step-by-Step Solution:

1. **Understand Ignition Temperature**:
- The ignition temperature is the minimum temperature at which a substance starts to burn. For wood, this temperature is crucial to know when considering how to extinguish a fire.

**Hint**: Remember that ignition temperature is the point where combustion begins.

2. **Identify the Options**:
- The question likely provides several options, including substances like water, oil, kerosene, and carbon dioxide. We need to evaluate these options based on their ability to lower the temperature of the burning wood.

**Hint**: Look for substances that can cool down or smother a fire.

3. **Evaluate Water**:
- Water is commonly used to extinguish fires. When poured on a burning log, it absorbs heat, lowering the temperature of the wood below its ignition temperature. Additionally, water turns into steam, which can help cut off the oxygen supply.

**Hint**: Consider how water interacts with fire and heat.

4. **Evaluate Oil and Kerosene**:
- Both oil and kerosene are flammable substances that support combustion. Pouring these on a fire would increase the temperature and fuel the fire rather than extinguishing it.

**Hint**: Think about whether the substance is a fuel or a fire extinguisher.

5. **Evaluate Carbon Dioxide**:
- Carbon dioxide can extinguish fires by cutting off the oxygen supply, but it does not necessarily lower the temperature of the burning material below its ignition temperature. It acts more as a smothering agent.

**Hint**: Consider the primary function of carbon dioxide in fire extinguishing.

6. **Conclusion**:
- The best option that directly brings down the temperature of the burning wooden log below its ignition temperature is **water**. Therefore, the answer is water.

### Final Answer:
A substance used to bring down the temperature of a burning wooden log below its ignition temperature is **water**.