Matter and its properties. 3rd Grade Science Worksheets and Answer ... - Free Printable

Problem Description:

The task involves understanding the properties of water and how it behaves under different conditions. The image provided shows various scenarios involving water, such as boiling, freezing, and mixing with other substances. The goal is to analyze these scenarios and explain the behavior of water in each case.

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Solution and Explanation:

#### Scenario 1: Boiling Water
- Image Description: A pot of water on a stove is shown boiling.
- Explanation:
- When water is heated, its temperature increases until it reaches its boiling point (100°C at sea level).
- At the boiling point, water changes from a liquid to a gas (water vapor). This process is called vaporization or evaporation.
- Bubbles form because the water molecules gain enough energy to overcome the intermolecular forces holding them together in the liquid state.
- The steam rising from the boiling water is water vapor, which is invisible but can be seen as condensation when it cools down.

#### Scenario 2: Freezing Water
- Image Description: A glass of water placed in a freezer is shown turning into ice.
- Explanation:
- When water is cooled below its freezing point (0°C), it transitions from a liquid to a solid state.
- During freezing, water molecules slow down and arrange themselves into a crystalline structure, forming ice.
- Ice has a lower density than liquid water, which is why ice floats on water. This property is crucial for aquatic life, as ice forms on the surface of lakes and rivers, insulating the water below.

#### Scenario 3: Mixing Salt with Water
- Image Description: Salt is added to a beaker of water.
- Explanation:
- When salt (sodium chloride, NaCl) is dissolved in water, it dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻).
- Water molecules surround these ions due to their polar nature, breaking the ionic bonds in the salt crystal lattice.
- This process is called dissolution. The resulting solution has a lower freezing point and a higher boiling point compared to pure water, a phenomenon known as colligative properties.

#### Scenario 4: Water Droplets on a Leaf
- Image Description: Water droplets are shown forming on a leaf.
- Explanation:
- Water droplets form on leaves due to the cohesive and adhesive properties of water.
- Cohesion refers to the attraction between water molecules, which causes them to stick together and form droplets.
- Adhesion refers to the attraction between water molecules and the surface of the leaf. These forces balance each other, allowing water to "bead up" rather than spreading out evenly.
- This behavior is also influenced by the waxy coating on the leaf surface, which repels water (a property called hydrophobicity).

#### Scenario 5: Water Flowing Through a Funnel
- Image Description: Water is poured through a funnel into a container.
- Explanation:
- Water flows smoothly through the funnel due to its fluid nature.
- The shape of the funnel helps direct the flow of water into a smaller opening, demonstrating how water adapts to the shape of its container.
- This behavior is consistent with water being a liquid, which takes the shape of its container but maintains a fixed volume.

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Summary of Key Properties of Water:

1. Boiling Point: Water boils at 100°C (at sea level) and turns into vapor.
2. Freezing Point: Water freezes at 0°C and turns into ice.
3. Solubility: Water is an excellent solvent, dissolving many substances like salt.
4. Cohesion and Adhesion: Water molecules stick to each other (cohesion) and to surfaces (adhesion), forming droplets.
5. Fluidity: Water flows and takes the shape of its container.

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Final Answer:

The behaviors observed in the scenarios demonstrate the following properties of water:
- Boiling: Transition from liquid to gas at 100°C.
- Freezing: Transition from liquid to solid at 0°C.
- Dissolution: Ability to dissolve substances like salt.
- Surface Tension: Formation of droplets due to cohesion and adhesion.
- Fluidity: Ability to flow and adapt to the shape of containers.

$$
\boxed{\text{Water exhibits boiling, freezing, dissolution, surface tension, and fluidity.}}
$$