The hot air balloon rises because it is

Options

A. denser than air
B. less dense than air
C. equally dense as air
D. The given statement is wrong

Answer

To answer the question "The hot air balloon rises because it is...", we need to understand the concept of density and how it relates to the behavior of gases when heated. Here’s a step-by-step solution:

### Step 1: Understand the concept of density
Density is defined as the mass of an object divided by its volume. It determines whether an object will float or sink in a fluid (like air). If an object is less dense than the fluid it is in, it will rise.

**Hint:** Remember that density is a measure of how much mass is contained in a given volume.

### Step 2: Analyze what happens when air is heated
When air inside the hot air balloon is heated, the particles of air gain energy. This increased energy causes the particles to move faster and spread apart.

**Hint:** Think about how heating affects the movement of particles in a substance.

### Step 3: Compare the density of hot air to cold air
As the air inside the balloon heats up, the number of air particles in a given volume decreases because they are moving apart. This means that the density of the hot air inside the balloon becomes less than the density of the cooler air outside the balloon.

**Hint:** Consider how the spacing of particles changes when they are heated.

### Step 4: Conclude why the balloon rises
Since the density of the hot air inside the balloon is less than the density of the cooler air outside, the balloon experiences an upward buoyant force. This is why the hot air balloon rises.

**Hint:** Relate the concept of buoyancy to the difference in densities.

### Final Answer
The hot air balloon rises because it is **less dense than air**.