From the following list of metals, choose the metal which fits into the given description.
Zinc, Sodium, Silver, Lead, Iron.
This metal reacts violently with cold water. It melts into a globule and darts about freely on the surface of water.

Explanation

To solve the question, we need to identify the metal from the given list that reacts violently with cold water, melts into a globule, and darts about freely on the surface of the water.

### Step-by-Step Solution:

1. **Understanding the Properties of Metals**:
- We need to consider the properties of each metal listed: Zinc, Sodium, Silver, Lead, and Iron. Specifically, we are looking for a metal that reacts violently with cold water.

2. **Analyzing Each Metal**:
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