Physical Changes Worksheet

Materials change between, solids, liquids and gases:

	melting		evaporation

SOLID		LIQUID		GAS

	freezing		condensation

These are physical changes which can be reversed. When materials change in this way, it is called changing state.

To be able to talk about and describe these changes, we must understand the science vocabulary associated with each of the physical changes. Let's check on that.

Ice cube

A solid changing to a liquid is called...

runny

frozen

melting

evaporating

Bottle of oil

Liquids at room temperature are melted solids.

Which THREE of these materials are liquids at room temperature?

butter

olive oil

gravy

toffee

mercury

Nail varnish

Some liquids evaporate into gases much quicker than others.

This quick-drying property can be observed in which THREE of these liquids?

perfume

nail varnish

engine oil

roll-on deoderant

treacle

FREEZING describes which of these reversible changes?

gas to liquid

liquid to solid

solid to liquid

liquid to gas

THREE of these materials, which are solid at room temperature, are frozen liquids.

Which three are they?

wax

concrete

chocolate

ceramic bowl

butter

Which TWO physical changes of state occur as a result of losing heat / energy?

condensing

evaporating

freezing

Condensing describes which physical change?

making soup

liquid to gas

gas to liquid

Which TWO of these contain condensed gas?

helium balloon

aerosol can

lighter

bicycle tyres

Which TWO physical changes of state occur as a result of gaining heat / energy?

evaporating

condensing

melting

ANSWERS

Question 1

Ice cube

A solid changing to a liquid is called...

CORRECT ANSWER

melting

EDDIE SAYS

Yes, when a solid is warmed up enough, it MELTS to form a liquid. A good example is your long-awaited ice cream on a hot, sunny day - you have to eat it fast before it all starts melting and running down your hand! That's solid turning to liquid.

ANSWERS

Question 2

Bottle of oil

Liquids at room temperature are melted solids.

Which THREE of these materials are liquids at room temperature?

CORRECT ANSWER

olive oil
gravy
mercury

EDDIE SAYS

Mercury is the only METAL which is liquid at room temperature. As it gets cooler, olive oil becomes cloudy and eventually solid! Butter needs to be kept cool as, even in the room on a hot day, it can start to melt.

ANSWERS

Question 3

When a liquid changes to a gas we say it is....

CORRECT ANSWER

evaporating

EDDIE SAYS

You've often watched evaporation - put a kettle of water on to boil and just a few minutes later there's steam coming out of the spout. That's liquid being turned to gas.

ANSWERS

Question 4

Nail varnish

Some liquids evaporate into gases much quicker than others.

This quick-drying property can be observed in which THREE of these liquids?

CORRECT ANSWER

perfume
nail varnish
roll-on deoderant

EDDIE SAYS

Designers and manufacturers use this property when they make their products. See if you can find some more examples at home!

ANSWERS

Question 5

FREEZING describes which of these reversible changes?

CORRECT ANSWER

liquid to solid

EDDIE SAYS

Freezing, as an idea, is fairly easy - liquid turning to solid. We associate it with being cold, like water turning to ice, but in science the language we use is much more precise. Whilst you think of freezing as 'cold', it often isn't: iron freezes at over 1500°C! That's molten iron, turning to solid iron, at an extremely hot temperature.

ANSWERS

Question 6

THREE of these materials, which are solid at room temperature, are frozen liquids.

Which three are they?

CORRECT ANSWER

wax
chocolate
butter

EDDIE SAYS

Candle wax melts to form liquid wax, as you'd see around the wick of the candle. Fats, such as butter, melt to become oils, and chocolate melts easily in your hand. Concrete and ceramics, like pottery, don't melt.

ANSWERS

Question 7

Which TWO physical changes of state occur as a result of losing heat / energy?

CORRECT ANSWER

condensing
freezing

EDDIE SAYS

That needed some thought! If something is losing heat it's getting ..... cooler! So which are changes that mean the substance is getting colder - yes, condensing (gas to liquid) and freezing (liquid to solid).

ANSWERS

Question 8

Condensing describes which physical change?

CORRECT ANSWER

gas to liquid

EDDIE SAYS

It's not always easy to picture this, so picture a steamy bathroom. Lots of water vapour fills the air. What's happening to all the cold surfaces (mirror, tiles, toilet)? Yes, they are all dripping with water. That's because the hot steam has touched the cold surface and changed from gas to liquid. We call that CONDENSATION (of course!).

ANSWERS

Question 9

Which TWO of these contain condensed gas?

CORRECT ANSWER

aerosol can
lighter

EDDIE SAYS

Both the aerosol can and the lighter contain gases under pressure that have turned to liquid. When the nozzle is pressed, the pressure is released, and the gas escapes. Bicycle tyres contain air under pressure, but it doesn't turn to liquid (fortunately - it would be really uncomfortable to ride on and would be at minus 200°C!).

ANSWERS

Question 10

Which TWO physical changes of state occur as a result of gaining heat / energy?

CORRECT ANSWER

evaporating
melting

EDDIE SAYS

Again, think about it first: a substance is getting hotter and changing state, so that means it's either melting (solid to liquid) or evaporating (liquid to gas). Keep working at it - practise makes perfect!