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2nd Grade Science (Next Generation Science Standards) • Earth’s Systems: Processes that Shape the Earth

Where Is All the Water?

Let's explore how water shows up in many different places and forms all around our amazing Earth!

Explore the lesson 7 min read
A microscope with leaf and experiment flask for elementary science discovery
Inside this lesson 9 sections 4 questions 5 figures

SECTION 1

What's Happening? 🔍

🔍 ANCHORING PHENOMENON

Imagine you wake up on a cold winter morning. You look out your window and see ice covering a puddle outside. Later, the sun comes out and the ice melts. By afternoon, the puddle is getting smaller. Where did the water go?

Now think about a hot summer day. You see big, fluffy clouds in the sky. Then it starts to rain! The rain fills up puddles, streams, and lakes. Water seems to be everywhere — but it looks different in different places!

Water Vapor(in clouds)Liquid Water(lake)Ice(frozen puddle)Snow
A picture showing water as ice on a puddle, liquid water in a lake, and clouds made of water in the sky
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💭 Thinking Questions

SECTION 2

Big Ideas About Water 💧

Water is one of the most important things on Earth. People, animals, and plants all need water to live. But water does not stay in just one place. And it does not always look the same!

Let's learn about where water is found and the different forms it can take.

1

Water Is in Many Places

Water is found in oceans, rivers, lakes, and streams. It is also underground and in the air! Even clouds are made of tiny bits of water.
2

Water Has Different Forms

Water can be a liquid (like the water you drink). It can be a solid (like ice and snow). It can even be a gas called water vapor (the invisible gas in the air).
3

Water Changes Form

Water can change from one form to another. When water gets very cold, it freezes and becomes ice. When ice gets warm, it melts and becomes liquid water. When liquid water gets really warm, it can turn into water vapor and go into the air. That is called evaporation.

SECTION 3

Let's Try It! 🔬

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🧪 LET'S TRY THIS!

Materials You Need:

  • A small cup of water
  • A freezer
  • A sunny window or warm spot

Steps:

  • Pour water into the cup. Look at it. This is liquid water.
  • Put the cup in the freezer. Wait a few hours. Take it out. Now it is ice — solid water!
  • Set the cup by a sunny window. Watch what happens. The ice slowly melts back into liquid water.
  • Leave the cup there for a whole day. Is there less water now? Some of it turned into water vapor and went into the air!

What to notice: Water can change from liquid to solid and back again. It can also seem to disappear into the air!

The Three Forms of WaterICE(Solid)WATER(Liquid)~WATER VAPOR(Gas)MeltsFreezesEvaporatesCondensesWhere Can We Find Each Form?Ice: glaciers, frozen ponds, snow, icebergsLiquid: oceans, rivers, lakes, rain, puddlesVapor: clouds, fog, steam, invisible in air
The three forms of water: ice (solid), liquid water, and water vapor (gas), with arrows showing how they change

SECTION 4

What We Discovered 🌊

When we do the cup experiment, we can see water change. The liquid water becomes solid ice in the freezer. The ice melts back into liquid water in the sun. And some of the water seems to disappear! It turns into water vapor — a gas we cannot see.

These same changes happen all around Earth. Oceans hold most of Earth's water as a liquid. Glaciers and the ice caps at the North and South Poles hold water as solid ice. And there is always water vapor in the air around us.

Places Where Water Is Found on Earth

PlaceForm of Water
🌊 Oceans and seasLiquid
🏞️ Rivers and streamsLiquid
🏔️ Glaciers and ice capsSolid (ice)
❄️ Snow on mountainsSolid (snow)
☁️ CloudsTiny water drops and ice
💨 Air around usGas (water vapor)
🌧️ RainLiquid
🕳️ UndergroundLiquid

SECTION 5

Do You See the Pattern? 🔁

Scientists always look for patterns. A pattern is when something happens the same way again and again.

Here is a pattern we can see with water: When things get cold, water turns into a solid. When things get warm, water turns into a liquid or a gas. Temperature makes water change!

This same pattern happens in other places too. Let's look!

When It Gets Cold...When It Gets Warm...
❄️ Puddles freeze into ice☀️ Ice melts into water
🧊 Water in pipes can freeze💧 Frozen pipes thaw and flow
⛄ Snow covers the ground🌸 Snow melts in spring
🏔️ Mountain tops stay icy🏞️ Warm valleys have flowing rivers
Water on Earth: It's Everywhere!🌊 OCEANSMost of Earth's water!❄️ ICE & SNOW🏞️ RIVERLAKE🕳️ UNDERGROUND WATER☁️ CLOUDS💨 AIR(water vapor)🌧️ RAINPATTERN: Cold places have solid water. Warm places have liquid or gas water.
Water on Earth: It's Everywhere!

SECTION 6

Water in Our Lives 🌍

People use science about water every day! Here are some ways people use what they know about water and its forms.

1

❄️ Keeping Food Fresh

We put food in the freezer. The cold turns the water inside food into ice. This keeps our food fresh for a long time!
2

🌧️ Collecting Rainwater

Some people collect rain in buckets or barrels. They use it to water their gardens. They know rain is liquid water falling from clouds!
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🏗️ Design Challenge: Can You Catch Water?

Try this: On a humid day, put a cold glass of water outside. Watch what happens to the outside of the glass. Where did those water drops come from? They came from water vapor in the air!

SECTION 7

Key Vocabulary 📖

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📖 KEY VOCABULARY
  • Liquid — Water that flows and you can pour. The water you drink is a liquid.
  • Solid — Water that is hard and frozen. Ice and snow are solid water.
  • Water vapor — Water that has turned into a gas. You cannot see it, but it is in the air all around us.
  • Freeze — When liquid water gets very cold and turns into ice.
  • Melt — When ice gets warm and turns back into liquid water.

SECTION 8

Practice: Show What You Know! ✏️

Question 1: Warm-Up

Marcus visits a mountain in winter. He sees white stuff covering the top of the mountain. What form of water is Marcus most likely seeing?
  • A. Water vapor in the air
  • B. Snow and ice
  • C. A flowing river
  • D. A warm puddle
Show answer
The correct answer is B. In winter, the white stuff covering a mountain top is snow and ice. Snow and ice are solid forms of water found in cold places on Earth. A is wrong because water vapor is an invisible gas — you cannot see it as white stuff on a mountain. C is wrong because a flowing river is liquid water, not the white covering described on the mountain. D is wrong because a warm puddle is liquid water found on flat ground, not a white covering on a cold mountain top.

Question 2: Building Skills

Priya is making a list of places where water is found on Earth. Which list shows places where water can be found?
  • A. Oceans, rivers, and glaciers
  • B. Deserts, rocks, and sand dunes
  • C. Trees, flowers, and grass
  • D. Mountains, valleys, and plains
Show answer
The correct answer is A. Oceans, rivers, and glaciers are all places where water is found on Earth. Oceans and rivers hold liquid water, and glaciers are large bodies of ice. B is wrong because deserts, rocks, and sand dunes are landforms, not places known for holding water. C is wrong because trees, flowers, and grass are plants, not places where water is found. D is wrong because mountains, valleys, and plains are landforms that describe the shape of the land, not bodies of water.

Question 3: Thinking Deeper

After a rainstorm, Kenji notices a puddle on the sidewalk. The next day, the puddle is gone and the sidewalk is dry. What most likely happened to the water in the puddle?
  • A. The water disappeared and no longer exists anywhere.
  • B. The water changed to water vapor and went into the air.
  • C. The water turned into a rock on the sidewalk.
  • D. The water froze into ice underground.
Show answer
The correct answer is B. When the sun warms a puddle, the liquid water changes into water vapor, which is a gas that goes into the air. The water is still there — it just moved to a different place in a different form! A is wrong because water does not disappear — it changes form and moves to different places. C is wrong because water does not turn into rocks; water and rocks are completely different materials. D is wrong because on a normal day after a rainstorm, the puddle water does not freeze underground — it evaporates into the air.

Question 4: Challenge

Amara's class is learning that water is found in many forms on Earth. She draws a picture of a lake, a cloud, and an icy pond. Which statement best explains what Amara's picture shows about water on Earth?
  • A. Water is only found as a liquid in lakes.
  • B. Water can be found as a liquid, a gas in clouds, and a solid like ice in different places on Earth.
  • C. Water can only be found in cold places on Earth.
  • D. Clouds and ice are not made of water.
Show answer
The correct answer is B. Amara's picture shows three different forms of water: the lake has liquid water, the cloud has tiny water droplets and water vapor (gas), and the icy pond has solid water (ice). This shows that water exists in different forms in different places on Earth. A is wrong because Amara's picture also includes a cloud and ice, not just a lake, so water is not only found as a liquid. C is wrong because the picture shows a lake and a cloud, which can be found in warm and cool places — water is not only in cold places. D is wrong because clouds contain tiny water droplets and ice is frozen water, so both are made of water.

SECTION 9

What's Next? 🔮

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🔮 WHAT'S NEXT?

Varsity Tutors • 2nd Grade Science (NGSS) • Water on Earth