krit.club logo

A Journey through States of Water - How can We change the States of Water?

Grade 6CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

Water exists in three states: Solid (Ice), Liquid (Water), and Gas (Water Vapour).

•

Melting: The process by which ice (solid) changes into water (liquid) upon heating. This occurs at 0∘C0^\circ \text{C}.

•

Freezing: The process by which water (liquid) changes into ice (solid) upon cooling. The freezing point of pure water is 0∘C0^\circ \text{C}.

•

Evaporation: The process of conversion of water (liquid) into water vapour (gas). This can happen at any temperature but is faster at higher temperatures.

•

Boiling: The rapid conversion of water into water vapour at a specific temperature called the boiling point. For pure water, this is 100∘C100^\circ \text{C}.

•

Condensation: The process where water vapour (gas) loses heat and changes back into liquid water. Example: Dew drops on grass or water droplets on the outer surface of a cold glass.

•

The Water Cycle: A continuous journey of water from the earth's surface to the atmosphere and back, involving evaporation, transpiration, condensation, and precipitation.

•

Temperature is measured using a thermometer, and the standard unit is Degree Celsius (∘C^\circ \text{C}).

📐Formulae

Ice (Solid)→HeatingWater (Liquid)→HeatingWater Vapour (Gas)\text{Ice (Solid)} \xrightarrow{\text{Heating}} \text{Water (Liquid)} \xrightarrow{\text{Heating}} \text{Water Vapour (Gas)}

Water Vapour (Gas)→CoolingWater (Liquid)→CoolingIce (Solid)\text{Water Vapour (Gas)} \xrightarrow{\text{Cooling}} \text{Water (Liquid)} \xrightarrow{\text{Cooling}} \text{Ice (Solid)}

Freezing Point=0∘C\text{Freezing Point} = 0^\circ \text{C}

Boiling Point=100∘C\text{Boiling Point} = 100^\circ \text{C}

💡Examples

Problem 1:

A beaker of water is at 25∘C25^\circ \text{C}. If it is heated until it reaches its boiling point, by how many degrees does the temperature increase?

Solution:

The boiling point of water is 100∘C100^\circ \text{C}. The initial temperature is 25∘C25^\circ \text{C}.

100−2575\begin{array}{r} 100 \\ - 25 \\ \hline 75 \end{array}

The temperature increases by 75∘C75^\circ \text{C}.

Explanation:

To find the increase, we subtract the starting temperature from the final boiling temperature (100∘C−25∘C100^\circ \text{C} - 25^\circ \text{C}).

Problem 2:

Identify the process: You take a cold bottle of juice out of the refrigerator and notice water droplets forming on the outside of the bottle after a few minutes.

Solution:

The process is Condensation.

Explanation:

Water vapour present in the surrounding air comes in contact with the cold surface of the bottle. It loses heat energy and changes from a gaseous state back into liquid droplets.

Problem 3:

If the temperature of a room is 32∘C32^\circ \text{C} and it drops by 12∘C12^\circ \text{C} during the night, what is the new temperature?

Solution:

32−1220\begin{array}{r} 32 \\ - 12 \\ \hline 20 \end{array}

The new temperature is 20∘C20^\circ \text{C}.

Explanation:

A drop in temperature indicates subtraction from the original value.

How can We change the States of Water? Class 6 Notes & Examples