E. Earth and Space Systems · Air and Water in the Environment

What Is Water Like?

E2.1 A1.2 A1.5About 35 minutes

Learning goals

I can describe properties of water: it flows, takes the shape of its container and is clear.
I can show that water drops stick together.
I can test which things dissolve in water and which things float or sink.
I can compare air and water.

Words to know

liquid
A kind of matter that flows and takes the shape of its container. Water is a liquid.

flow
To move along smoothly, like water pouring from a jug.

container
Something that holds things, like a cup, a bowl or a bottle.

dissolve
To mix into water so completely that you can't see the bits anymore, like sugar in tea.

float
To stay on top of the water.

sink
To drop down to the bottom of the water.

observe
To use your senses carefully to notice things.

Splash!

You wash your hands in it. You drink it. You splash in it at the beach and skate on it in winter. What is it? Water!

Water is one of the most important things on Earth. Today you will be a scientist and find out what water is like.

Water is a liquid

Most of the water we use every day is a liquid. A liquid:

flows. You can pour it.
takes the shape of its container. In a tall glass it is tall and thin. In a bowl it is short and wide.
keeps the same amount when you pour it into a new container. Nothing is added and nothing is lost.

If you pour water on a table, it spreads out into a puddle, because there is no container to hold it.

A tall glass, a wide bowl and a jug of clear water on a kitchen table. — The same water can be tall and thin in a glass or short and wide in a bowl. Water takes the shape of its container. AI-generated image

The same cup of water is tall in a glass, wide in a bowl and flat as a puddle. Water takes the shape of whatever holds it.

More properties of water

Clean water is clear. You can see through it.
Pure water has no colour, no smell and no taste.
Water makes things wet. Some materials, like paper towels and sponges, soak it up.
Water drops stick together. Drip water on a coin and it piles up into a dome before it spills over!
Water has mass. One litre of water has a mass of about 1 kilogram. A big jug of water feels heavy!
Many things dissolve in water, like salt and sugar. Other things, like sand and oil, do not dissolve.
Some objects float on water. Others sink.
Water can be a solid (ice), a liquid (water) or a gas (water vapour). You will learn more about this in the next lesson.

Remember from Grade 1

In Grade 1 you sorted materials that absorb water (like a sponge) and materials that are waterproof (like a raincoat). Those are properties of the materials. Today we are looking at properties of water itself.

Worked example

Let's sort: Does it dissolve?

Mila puts a spoonful of each thing in its own cup of warm water and stirs: salt, sand, sugar, cooking oil. Which ones dissolve?

Salt: after stirring, the water looks clear again. The salt is still there (the water would taste salty), but we can't see it. Salt dissolves.
Sand: it swirls around, then settles on the bottom. Sand does not dissolve.
Sugar: it disappears into the water like the salt. Sugar dissolves.
Oil: it makes a layer that floats on top of the water, even after stirring. Oil does not dissolve.

Salt and sugar dissolve. Sand and oil do not dissolve.

Mila's dissolve test. Salt and sugar seem to disappear, sand settles on the bottom, and oil floats in a layer on top.

Thing	What we observed	Dissolves?
salt	disappears after stirring	yes
sugar	disappears after stirring	yes
sand	settles on the bottom	no
cooking oil	floats on top in a layer	no

Mila's results

Worked example

Let's compare air and water

How are air and water the same? How are they different?

Same: both take up space. Both have mass. Both can move (wind and flowing water). Living things need both.
Different: we can see water, but we can't see clean air.
Different: water is a liquid that stays at the bottom of a cup. Air is a gas that spreads out to fill the whole space.
Different: air can be squeezed into a smaller space. Water can hardly be squeezed at all.

Air and water both take up space, have mass and can move. Water is a liquid you can see. Air is a gas you can't see, and it can be squeezed.

Property	Air	Water
Can we see it?	no (clean air)	yes
Takes up space?	yes	yes
Has mass?	yes, very light	yes, 1 litre is about 1 kg
Flows or moves?	yes (wind)	yes (pours, rivers)
Can be squeezed smaller?	yes	hardly at all

Comparing air and water

Just for fun

Water is the world's best copycat. In a tall glass, it's tall. In a wide bowl, it's wide. In a rubber boot, it's boot-shaped! (Please don't drink that one.)

Hands-on activity

Water explorer stations

You need: water, a tall glass, a wide bowl, a measuring cup, a coin, an eye dropper or a spoon, small cups, salt, sugar, sand or dirt, and small objects to test (a cork, a coin, a crayon, a leaf, a plastic lid, a rock).

Shape. Measure 1 cup of water. Pour it into the tall glass, then into the bowl, then back into the measuring cup. Is it still 1 cup?
Drops on a coin. Predict how many drops of water fit on a coin before it spills. Add drops one at a time and count. Look at the bump of water from the side!
Dissolve test. Stir a spoonful of salt, sugar and sand into separate cups of water. Which ones disappear?
Float or sink. Predict first, then test each small object. Sort them into two piles.
Make a chart of what you found.

Safety: Only taste something if a grown-up says it is safe. Wipe up spills.

Your turn

What do we call something that flows and takes the shape of its container?

You pour water from a tall glass into a wide bowl. Does the amount of water change?

Does sugar dissolve in water?

Does sand dissolve in water?

Name one way air and water are the same.

Name one way air and water are different.

What happens when you drip water on a coin, drop by drop?

More practice: warm-up

Is clean water clear or cloudy?

Can you pour water?

Does salt dissolve in water?

Name one thing that floats on water.

Name one thing that sinks in water.

More practice: on your own

Oil and water are stirred together. After a minute, what do you see?

A 2-litre jug of water and an empty 2-litre jug. Which is heavier? Why?

Why does spilled water spread out on a table?

You stir salt into water and it disappears. Is the salt gone? How could you tell?

Which property of water helps a sponge clean up a spill?

Challenge

Eli says, "If I pour water into a bigger bowl, I get more water." Is he right? How could he test it?

Sara counted 18 drops on a nickel and 27 drops on a loonie. Why do you think the loonie held more?

Which is easier to squeeze into a smaller space: a balloon of air or a balloon of water? Why?

Check your understanding

Quiz

Water poured from a glass into a bowl...

Which one dissolves in water?

Clean, pure water is...

What happens when you drip water drops on a coin?

How are air and water the same?

About how much mass does 1 litre of water have?

For parents and teachers

Big idea (E2.1): Water has properties we can observe: it flows, takes the shape of its container while keeping the same amount, is clear and (when pure) has no colour, smell or taste, has mass, dissolves some substances, and its drops cling together. Comparing air and water helps children notice that both are real matter.

How to help: The kitchen is the best lab. Let your child pour, measure and stir. Ask "What do you predict?" before each test and "What did you observe?" after (A1.2, A1.5).

Common difficulties:

Thinking a dissolved thing is gone. Let a little salt water evaporate on a dark plate over a few days: the salt reappears.
Thinking a wide bowl has less (or more) water than a tall glass. Measure back and forth to prove the amount stays the same.
Mixing up "dissolve" and "melt". Melting is ice turning to water from warmth. Dissolving is something mixing into water.

Safety: Don't let children taste test liquids unless you have made them. Wipe up spills.