Soil Formation: A step-by-step diagram showing how soil develops from parent rock through physical and chemical weathering, organic matter, and tiny particles.

To solve the problem and explain how soil is formed using the provided keywords and images, let's break down the process step by step. The goal is to create a step-by-step diagram that illustrates the formation of soil.

Keywords and Images Provided:

1. Parent Rock
2. Physical Weathering
3. Chemical Weathering
4. Plants
5. Tiny Particles

Step-by-Step Explanation:

#### 1. Parent Rock
- Description: Soil formation begins with solid rock, known as the parent rock. This is the primary source material for soil.
- Image Representation: The large rock in the background represents the parent rock.

#### 2. Physical Weathering
- Description: Over time, physical weathering occurs due to natural forces such as temperature changes, wind, water, and ice. These forces break the parent rock into smaller pieces without changing its chemical composition.
- Image Representation: The cracks or fragmentation in the rock indicate physical weathering.

#### 3. Chemical Weathering
- Description: Chemical weathering involves the breakdown of rocks through chemical reactions. This can occur due to exposure to water, oxygen, and acids (e.g., from rain or plant roots). These reactions alter the minerals in the rock, further breaking it down into smaller particles.
- Image Representation: The gradual disintegration of the rock into finer particles indicates chemical weathering.

#### 4. Plants
- Description: Plants play a crucial role in soil formation. Their roots penetrate the fragmented rock, breaking it down further. Additionally, plants contribute organic matter to the soil when they die and decompose.
- Image Representation: The growing plant with roots extending into the ground shows how plants interact with the soil and contribute to its development.

#### 5. Tiny Particles
- Description: As physical and chemical weathering continue, the rock breaks down into tiny particles. These particles, along with organic matter from plants, form the basis of soil. Over time, these particles accumulate and mix with organic material to create fertile soil.
- Image Representation: The soil layer at the bottom of the image, rich in organic matter and fine particles, represents the final stage of soil formation.

Step-by-Step Diagram:

1. Parent Rock → Physical Weathering
- The parent rock is subjected to physical forces like temperature changes, wind, and water, causing it to crack and break apart.

2. Physical Weathering → Chemical Weathering
- The broken pieces of rock undergo chemical reactions due to exposure to water, oxygen, and other elements, further breaking them down into smaller particles.

3. Chemical Weathering → Plants
- Plants grow in the area, and their roots penetrate the fragmented rock, breaking it down further. Plants also add organic matter to the soil when they die and decompose.

4. Plants → Tiny Particles
- The combination of broken-down rock particles and organic matter from plants forms the soil. Over time, this mixture becomes rich and fertile.

Final Answer:

The step-by-step process of soil formation can be summarized as follows:

1. Parent Rock → Physical Weathering
2. Physical Weathering → Chemical Weathering
3. Chemical Weathering → Plants
4. Plants → Tiny Particles

This sequence illustrates how soil is formed from solid rock through the processes of weathering and the contribution of plants.

$$
\boxed{\text{Parent Rock} \rightarrow \text{Physical Weathering} \rightarrow \text{Chemical Weathering} \rightarrow \text{Plants} \rightarrow \text{Tiny Particles}}
$$