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C. Matter and Energy · Properties of Liquids and Solids

Properties of Solids and Liquids

C2.2 C2.1 A1.2 A1.5About 35 minutes
Learning goals
  • I can describe properties of solids.
  • I can describe properties of liquids.
  • I can explain that a liquid keeps the same amount even when it changes shape.
  • I can do a fair test to see which liquid flows fastest.

Words to know

property
Something we can observe about matter, like its shape, colour, or how it moves.
flow
To move along smoothly, the way water runs out of a tap.
runny
Flows quickly, like water or milk.
thick
Flows slowly, like honey or maple syrup.
grain
One tiny piece of a solid, like one grain of sand, salt, sugar or rice.
fair test
A test where we change only one thing and keep everything else the same.
predict
To make a smart guess about what will happen.

Remember from Grade 1

In Grade 1 you learned that materials have properties, like hard, soft, waterproof and flexible (bendy). A property is something we can observe with our senses.

Solids and liquids have properties too. Today you will become a property detective!

Properties of solids

A solid:

  • keeps its own shape. A block is still a block whether it sits on the table or in a box.
  • can be picked up and held.
  • can be hard (a rock), soft (a pillow), bendy (a rubber band) or stiff (a ruler). Even soft and bendy solids keep their own shape when you put them down.
  • stays the same size and shape when you move it to a different container.
A smooth grey rock, a wooden block, a small white pillow and a red rubber band in a row on a table.
These are all solids, but their properties are different: the rock is hard, the pillow is soft and the rubber band is bendy. AI-generated image

Properties of liquids

A liquid:

  • flows and can be poured.
  • takes the shape of its container.
  • can drip, splash and spill.
  • has a flat, level top when it sits still in a container.
  • cannot be held in your hands. It runs through your fingers.

Some liquids are runny and flow fast, like water and milk. Some liquids are thick and flow slowly, like honey, maple syrup and shampoo.

tall glassround bowlsquare dish
The same kind of liquid takes the shape of each container: tall in the glass, round in the bowl and flat in the square dish.

A liquid keeps the same amount

Pour 250 mL of water from a tall glass into a wide bowl. In the bowl, the water looks lower. Did some water disappear?

No! It only changed shape. Pour it back into the tall glass, and it comes up to the same line as before. A liquid changes its shape, but the amount stays the same (as long as none spills).

PropertySolidLiquid
Shapekeeps its own shapetakes the shape of its container
Can you hold it?yesno, it runs through your fingers
Does it flow or pour?noyes
When you move it to a new containersame shapenew shape, same amount
Examplesrock, block, spoon, applewater, milk, juice, honey
Comparing solids and liquids

Tricky ones: sand, sugar and rice

Sand, salt, sugar and rice can be poured. Are they liquids?

No! They are solids made of many tiny pieces called grains. Look at them with a magnifying glass. Each grain keeps its own shape.

Here is another clue. Pour rice onto a plate and it makes a pile. Pour water onto a plate and it spreads out flat. Liquids do not make piles!

rice (a solid)makes a pilewater (a liquid)spreads out flatPour each one onto a plate:
Rice pours, but it piles up because each grain keeps its own shape. Water spreads out flat. Liquids do not make piles!
Worked example

Let's test: Is rice a solid or a liquid?

Rice pours out of the bag. Is it a solid or a liquid?

  1. Look closely: Put a few grains on a dark plate. Each grain is a tiny, hard piece with its own shape.
  2. Pick one up: You can hold one grain between two fingers. It does not drip.
  3. Pour some: Pour a spoonful onto the plate. It makes a little pile. Water would spread out flat.
  4. Think: Every grain keeps its own shape. That is a property of a solid.

Rice is a solid. It pours only because it is made of many small grains, and each grain keeps its own shape.

Worked example

Let's do a fair test: the liquid race

Which liquid flows the fastest: water, maple syrup or honey?

  1. Question: Which liquid flows down a tilted tray the fastest?
  2. Predict: I think water will be fastest, because it is runny. I think honey will be slowest, because it is thick.
  3. Make it fair: Use the same amount of each liquid (1 small spoonful). Put them all on the same starting line. Tilt the tray at the same angle for all of them, at the same time. We only change one thing: the kind of liquid.
  4. Observe: Lift one end of the tray on a book. Watch the liquids run down.
  5. Record: Water reached the bottom first. Maple syrup was next. Honey moved very slowly.

Water flowed the fastest. Honey flowed the slowest. Runny liquids flow faster than thick liquids. Our prediction was right! (If your results are a little different, that is okay. Scientists share what they really see.)

Just for fun

In a liquid race, honey would never win a medal. But it would get the prize for most sticky fans!

LiquidRunny or thick?Order it finished
waterrunny1st
maple syrupthick2nd
honeyvery thick3rd
Our liquid race results chart
Hands-on activity

Liquid race at home

You need: a baking tray with sides, a book, masking tape, a spoon, and 3 or 4 liquids from the kitchen such as water, milk, honey, maple syrup, ketchup or cooking oil. Use only food liquids for this test.

  1. Put a strip of tape across one end of the tray. This is the starting line.
  2. Predict: Which liquid will win? Which will come last? Write or draw your prediction.
  3. With a grown-up, put one small spoonful of each liquid on the starting line, spread apart.
  4. Lift that end of the tray and rest it on a book. Watch!
  5. Record the order in a chart: 1st, 2nd, 3rd.
  6. Share your results. Was your prediction right? Use the words runny and thick.

Bonus: Pour 1 cup of water into a tall glass, a bowl and a pie plate, one at a time. Is it still the same amount each time?

Safety: Wipe up spills right away so no one slips. Wash the tray when you are done.

Your turn

1

Name two properties of a solid.

2

Name two properties of a liquid.

3

Is maple syrup runny or thick?

4

You pour juice from a carton into a round cup. What shape is the juice now?

5

Is sugar a solid or a liquid? How do you know?

6

Which flows faster: water or honey?

7

In a fair test, how many things do we change?

More practice: warm-up

1

Can you hold a block in your hand?

2

Can you hold water in your open hand?

3

Does a liquid take the shape of its container?

4

Is milk runny or thick?

5

Does a toy car change shape when you put it in a box?

More practice: on your own

1

Leo pours his water from a tall glass into a wide bowl. He says, "Some water disappeared, because it looks lower!" Is he right?

2

Sand pours out of a pail. Why is sand still a solid?

3

A pillow is soft and squishy. Is it a solid or a liquid? Explain.

4

Put these in order from fastest to slowest flowing: honey, water, shampoo.

5

In the liquid race, why must we use the same amount of each liquid?

Challenge

1

You have a bowl of rice and a bowl of water. Without touching either one, how could you show which is the liquid?

2

Why is ketchup sometimes hard to get out of the bottle?

3

Sam's liquid race: he used 1 spoon of water and 3 spoons of honey, and he tilted the tray more for the honey. Is this a fair test? How can he fix it?

Check your understanding

Quiz

1.

Which is a property of every liquid?

2.

Which liquid is thick?

3.

Rice can be poured. Rice is a...

4.

You pour 250 mL of milk from a tall glass into a wide bowl. How much milk is in the bowl?

5.

Which one keeps its own shape?

6.

In a fair liquid race, what should be different for each liquid?

For parents and teachers

Big idea: Solids keep their own shape; liquids flow, take the shape of their container and keep the same amount when poured into a different container (C2.2). Liquids can be runny or thick. Grains such as sand, sugar and rice are solids even though they pour.

How to help: At bath time, pour water between different containers and ask, "Is it the same amount?" Pour it back to check. In the kitchen, compare how fast ketchup, syrup and milk pour.

About the experiment (Strand A): The liquid race is a fair test. Help your child name what stays the same (amount, starting line, tilt) and what changes (the liquid). Praise honest recording, even when results surprise you.

Common difficulties:

  • Thinking a liquid is "less" in a wide container. Many 7-year-olds believe this. Pouring back into the first glass is the best proof.
  • Calling sand or sugar a liquid. Use the "pile test" and a magnifying glass.
  • Calling soft solids (play dough, a pillow) liquids. Ask, "Does it flow by itself and fill the shape of a cup?"

Safety: Use only food liquids for the race. Wipe up spills right away.