Drop By Drop

What is water?
Water is a colourless, tasteless and odourless liquid that we need to live. It is found everywhere — in rivers, ponds, seas, clouds and inside living things. Water is very important for drinking, cooking, cleaning and for plants and animals.

Where does water come from?

• Rain falls from clouds and fills rivers, ponds and lakes.
• Rivers and streams carry water to bigger rivers and to the sea.
• Wells, hand pumps and taps give us water at home.

Three forms of water

• Liquid — water in a glass, river or sea.
• Solid — ice, formed when water freezes.
• Gas — water vapour, when water evaporates into the air.

The water cycle (simple)
Sun heats water from lakes and seas → water evaporates and forms clouds → clouds bring rain → rain fills rivers, lakes and the ground. This keeps water moving round and round.

Why water is important

• We drink water to stay healthy.
• Plants need water to grow.
• Water helps keep our bodies and homes clean.

How to save water

• Turn off the tap while brushing teeth.
• Fix leaking taps and pipes.
• Use a small bucket for washing and use leftover water for plants.

Simple facts
About 71% of the Earth’s surface is covered with water. Most of this is salty sea water; only a small part is fresh and safe to drink. We must protect and save fresh water.

What are sources of water?

Sources of water are places or ways from which we get water for drinking, cooking, cleaning, farming and other needs. Water comes from nature and from things people build.

Main natural sources

• Rain – Water that falls from clouds. Rain fills ponds, lakes and rivers and soaks into the ground.
• Rivers – Flowing fresh water that moves from hills to lowlands and finally to the sea.
• Lakes and Ponds – Still bodies of water that store fresh water.
• Groundwater – Water that is stored under the soil in rocks and sand. We get it by digging wells and using tube wells.
• Springs – Places where underground water comes out naturally.
• Glaciers and Snow – Ice on mountains that melt in summer and become rivers and streams.
• Seas and Oceans – Very large bodies of water. Most of this water is salty and cannot be drunk without treatment.

Man-made sources

• Taps and Pipelines – Water from rivers, lakes or groundwater that is cleaned and sent to our homes.
• Canals and Reservoirs – Built to store and carry water for farms and towns.

How water moves (simple water cycle)

• Evaporation: Sun heats water from oceans and lakes and turns it into vapor.
• Condensation: Vapor forms clouds.
• Precipitation: Clouds give rain or snow.
• Collection: Rainwater gathers into rivers, lakes or soaks into the ground.

Important facts for children

• Not all water on Earth is drinkable. Most is salty.
• Rainwater helps refill rivers and underground water (this is called recharge).
• We must save water by turning off taps, fixing leaks and using water carefully.

Why water is important
Water is a very important natural resource. All living things — people, animals and plants — need water to stay alive. Water is used at home, on farms, in factories and for many other jobs.

Main uses of water

• Drinking and cooking: Clean water is needed to drink and to prepare food safely.
• Personal hygiene: We use water for bathing, washing hands and brushing teeth to keep clean and healthy.
• Household chores: Water is used for washing clothes, dishes, cleaning floors and toilets.
• Farming (irrigation): Farmers use water to grow crops and feed animals.
• Plants and gardens: Water helps plants and trees grow and keeps gardens healthy.
• Industry and manufacturing: Factories use water to make products (paper, cloth, food items) and to cool machines.
• Generating electricity: Some power plants (like hydroelectric dams) use water to make electricity.
• Firefighting and public services: Water is used to put out fires and to keep public places clean.

Using water wisely
Because water is limited in many places, it is important to use it carefully. Simple habits — closing taps while brushing teeth, fixing leaks, using a mug to wash vegetables, watering plants early in the morning — save water. Schools and families can measure and compare water use and try to reduce waste.

What are the forms of water?

Water exists in three common forms:

• Solid (ice): Water becomes hard and keeps its shape when it is very cold. Example: ice cubes, snow.
• Liquid (water): This is the form we drink and use every day. Example: rivers, rain, tap water.
• Gas (water vapour): Invisible steam or vapour that mixes with the air. Example: steam from a kettle, humidity.

How does water change from one form to another?

• Melting: Solid → Liquid. Ice melts into water when heated or when temperature rises above the freezing point.
• Freezing: Liquid → Solid. Water turns into ice when cooled below the freezing point.
• Evaporation: Liquid → Gas. Water turns into vapour when it gets warm (or when its surface is exposed for a long time).
• Condensation: Gas → Liquid. Water vapour cools and becomes tiny drops of water (as on the outside of a cold glass or as clouds).
• Sublimation: Solid → Gas. Some solids (like very dry snow) can change directly into vapour without becoming liquid first.

The water cycle (Drop by Drop):

Sun heats water in oceans, rivers and lakes → evaporation (and transpiration from plants) → water vapour rises and cools → condensation forms clouds → clouds become heavy and release water as precipitation (rain, snow, hail) → water collects back in seas, rivers and groundwater. This cycle repeats, so the same water keeps changing its form.

Important temperatures (at sea level):

• Freezing point of water: 0 °C
• Boiling point of water: 100 °C

Simple experiments to see these changes:

• Put ice in a bowl and watch it melt into water (melting).
• Leave a wet plate in sunlight; the water will disappear over time (evaporation).
• Hold a cold metal spoon near steam from hot water and see tiny drops form (condensation).

The simple water cycle (also called the hydrological cycle) shows how water moves around Earth. The Sun heats water in oceans, lakes and rivers. This makes water change from liquid to water vapour. This process is called evaporation. Water vapour rises into the sky. When the vapour cools down, it changes back into tiny water droplets and forms clouds. This change is called condensation. When the droplets in clouds become large and heavy, they fall as precipitation — rain, snow or hail. The water that falls collects in rivers, lakes and oceans, and some soaks into the ground to become groundwater. This part is called collection. Then the Sun heats the water again and the cycle continues.

• Sun — source of heat that starts evaporation.
• Evaporation — liquid water turns into vapour.
• Condensation — vapour cools and becomes tiny droplets (clouds).
• Precipitation — droplets fall as rain, snow or hail.
• Collection — water gathers in oceans, rivers, lakes and underground.

Key points: the water cycle is continuous (it does not stop) and most of Earth’s water is in the oceans. The cycle keeps fresh water available for plants, animals and people.

Clean and safe water means water that is free from dirt, harmful chemicals and tiny living things called germs. We need clean water to drink, cook, bathe and keep our homes and schools healthy.

Where water comes from: rain, rivers, lakes, ponds, wells and groundwater. Most water on Earth is salty (in the oceans) and cannot be used directly. Only a small part of Earth’s water is fresh and usable.

Why water must be safe: dirty water can cause stomach ache, diarrhea and other illnesses. Germs and unsafe chemicals can get into water from open drains, dirty vessels, and broken pipes.

How to keep water clean and safe:

• Store water in clean, covered containers so dust and insects cannot get in.
• Wash hands with soap before touching drinking water or food.
• Make water safe at home by filtering (using a clean cloth or filter) and then boiling it to kill germs.
• Use water filters or water purification tablets when needed, and always follow instructions from adults.
• Do not throw rubbish or chemicals into ponds, rivers or drains.
• Save water by turning off taps when not in use, fixing leaks and using only what we need.

Simple facts children can remember: water boils at 100°C and freezes at 0°C (at sea level). One litre (1 L) equals 1000 millilitres (1000 mL) and about 1 litre of water weighs 1 kilogram.

What is Water Conservation?
Water conservation means using water carefully so we do not waste it. Water is precious because people, animals and plants need it to live. We must save it so there is enough for everyone now and in the future.

Why is it important?

• To make sure we have enough clean water to drink and cook.
• To help plants and animals survive.
• To keep rivers, lakes and the environment healthy.

How do we waste water?

• Leaving taps running while brushing teeth or washing hands.
• Taking very long baths or showers.
• Leaks from taps and pipes that are not fixed.

Simple ways to save water (easy for children):

• Turn off the tap while brushing your teeth. Use a cup if needed.
• Use a bucket for bathing instead of filling a big tub.
• Fix dripping taps or tell an adult to fix them.
• Water plants in the early morning or late evening so less water evaporates.
• Collect rainwater in a barrel to water plants or wash vegetables.
• Use a broom to clean the yard instead of a hose.

Small activity to try: Put a bucket under a dripping tap for one day and measure how much water collects. This shows how much is wasted and why fixing it helps.

What this topic is about
In the Class 3 EVS chapter 'Drop by Drop', students learn why every drop of water is precious. The 'Activities and Experiments' section helps children see, measure and understand water-related ideas by doing simple, safe hands-on tests. These activities show how water moves (evaporation, absorption, capillary action), how much water small leaks waste, and simple ways to clean or save water.

Key activities and how to do them (simple steps)

1. How many drops are in a teaspoon and in a litre?

1. Materials: eye dropper or pipette, clean teaspoon (5 ml), small bowl, marker and paper.
2. Steps: Use the dropper to count how many drops fill the teaspoon. Repeat 2–3 times and take the average number of drops per 5 ml.
3. Observation: You get the number of drops in 5 ml. Use that to calculate drops in 1 litre (1000 ml).
4. Learning: Understand tiny size of a drop and how many drops make a litre.

2. Measuring water wasted from a leaking tap

1. Materials: empty bottle or jug, stopwatch or clock, funnel (optional).
2. Steps: Put the jug under a leaking tap for a set time (for example 10 minutes). Measure the water collected. Calculate how much would be wasted in an hour, a day, a week.
3. Learning: Realise that even a slow drip wastes many litres over time and why fixing leaks matters.

3. Evaporation experiment (two bowls)

1. Materials: two identical shallow bowls, water, marker, notebook.
2. Steps: Fill both bowls equally and mark the water line. Cover one bowl with a lid or plate; leave the other open in sunlight. Check daily and measure how much water is left.
3. Observation: The open bowl will lose water faster (evaporation). Record how temperature and wind affect evaporation.
4. Learning: Understand evaporation and why open water bodies dry faster in sun.

4. Simple filtration (cleaning dirty water)

1. Materials: dirty water, cloth, sand, small stones, a plastic bottle cut in half to make a filter, bowl to collect filtered water.
2. Steps: Layer stones, sand and cloth in the bottle and pour dirty water slowly. Collect the filtered water and compare clarity before and after.
3. Learning: See how particles are removed but learn that filtered water may still need boiling before drinking.

5. Capillary action with coloured water

1. Materials: two cups, water, food colour, paper towel or celery stick.
2. Steps: Put coloured water in one cup and plain water in the other. Join them with a paper towel strip or place a celery stick with ends in both cups. Watch colour move into the plain water.
3. Learning: Water can climb up small spaces showing how plants take water from soil.

Classroom notes and safety
All activities use safe household items. Always supervise children, especially with small parts and coloured water. Emphasise that filtered water might still need boiling for drinking.

What is hygiene? Hygiene means keeping our body, clothes, home and surroundings clean so that we do not get sick. Clean habits stop germs (tiny living things) from entering our bodies.

How hygiene and health are connected

• Germs live in dirty water, on unwashed hands, on unclean food and in open drains. When they enter our mouth, nose or cuts, they can cause diseases like diarrhoea, fever, cough, cold, and skin infections.
• Good personal hygiene — such as washing hands, bathing, brushing teeth and keeping nails short — reduces the chance of getting sick.
• Household and community hygiene — such as safe storage of drinking water, clean toilets, proper waste disposal and no stagnant water — prevents spread of diseases and keeps the environment healthy.
• Saving water (a message from the chapter "Drop by Drop") is also linked to health: using water carefully ensures there is enough clean water for drinking, cooking and washing, which are essential for hygiene.

Simple hygiene rules for children

• Wash hands with soap for about 20 seconds at key times: before eating, after using the toilet, after playing outside, and after touching animals.
• Drink safe water — boiled or filtered if unsure — and keep water covered.
• Wash fruits and vegetables before eating.
• Brush teeth twice a day and bathe regularly.
• Keep nails short, wear clean clothes, and keep the house and utensils clean.

Why these matter Following these habits lowers the number of sick days, helps children attend school regularly, and keeps families and neighbours healthy. Small acts like fixing a leaking tap, covering water containers or using a dustbin help a lot.

Community means a group of people who live, work or study near each other — for example, families in a neighbourhood, children and teachers in a school, or people in a village. Every person in a community has certain responsibilities. Responsibility means doing the right things to help others and to keep our surroundings clean, safe and healthy.

In the chapter "Drop by Drop" we learn that water is very precious. A community must work together to save water and use it wisely so everyone has enough. Children, parents, teachers and leaders all have small duties that add up to big change.

What responsibilities can a child have?

• Turn off taps properly after use and report leaks to an adult.
• Use a mug or small bucket while bathing to avoid wasting water.
• Help collect and use rainwater for plants (rainwater harvesting).
• Keep common places clean and not throw rubbish in drains or ponds.
• Teach friends and family simple water-saving habits.

How the whole community helps:

• Fix leaking pipes and taps quickly to stop water loss.
• Create community tasks like cleaning drains, planting trees and setting rules for fair water use.
• Set up a water-saving plan at school: use taps with buckets for washing, reuse water for plants, and celebrate Water Day to learn more.

Why this is important: when everyone takes responsibility, water is saved, the area stays clean, people stay healthy, and we protect nature for the future. Small acts by many people — drop by drop — make a big difference.

Introduction
This topic explains the most important words and ideas from the Class 3 EVS chapter "Drop by Drop". Children learn what water is used for, where it comes from, why it must be saved and simple ways to protect and reuse it.

• Water – A clear liquid we drink and use for cooking, bathing, cleaning and growing plants.
• Freshwater – Water from rivers, lakes, wells and rain that we can use. It is different from saltwater (sea water).
• Saltwater – Water from the sea that is salty and not good to drink.
• Source – Where water comes from (rain, river, pond, well, tap).
• Groundwater – Water stored under the ground. It fills wells and springs.
• Rainwater harvesting – Collecting and storing rainwater for later use (for plants, washing, or recharging groundwater).
• Conserve / Conservation – To save something and use it carefully so there is enough for everyone.
• Pollution – Dirty things (like oil, garbage, chemicals) that make water unsafe to use.
• Purify / Filtration – Cleaning water to make it safe to drink.
• Leak – When water escapes from a pipe, tap or container and is wasted.

Key Concepts (simple explanations)

• Uses of water: Drinking, cooking, bathing, cleaning, farming and in factories.
• Why water is important: All living things need water to live and grow.
• Sources of water: Rain, rivers, lakes, ponds, wells and taps (which often get water from a treatment plant or groundwater).
• Saving water: Small actions—like turning off the tap while brushing, fixing leaks, and using a mug to wash—save lots of water over time.
• Collecting and reusing: Use leftover water for plants, or collect rainwater for washing and gardening.
• Keeping water clean: Don’t throw garbage or chemicals into water bodies; use dustbins and proper drains.

How to explain to a child: Water comes to us drop by drop. Every drop counts — if we waste little drops every day, we will not have enough later. Fixing leaks and collecting rain are like saving coins in a piggy bank for the future.