Properties of Liquids: Science Investigation at Green Bay High School September 2009.

The big question: Why do liquids behave the way they do?

(1)Liquids are made up of tiny particles. Here are some clues:Volume of alcohol = mlVolume of water = ml

Total volume after mixing = ml

When alcohol and water are mixed the total volume…….

……………………………………………………………

……………………………………………………………

…........................................................................................

Volume of peas = mlVolume of sand = ml

Total volume after mixing = ml

When peas and sand are mixed the total volume………..

…………………………………………………………...

…………………………………………………………...

……………………………………………………………

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Fill in the spaces with missing words.

Liquids can be poured from one container to another just like peas. When………. and sand are mixed the particles……… of are able to fill up the spaces between the pea particles. Liquids like…………… and water are made up of particles we call…………... When alcohol and water are mixed the…………. volume is less than the………….. volumes. Scientists call this the particle nature of matter. All matter is made up of small particles.

Words to use: alcohol, molecules, combined, peas, starting, sand.

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(2)What happens when liquids are heated?

Measure the temperature of water in a jug. Measure its temperature every minute after it is switched on until the water boils. Measure the temperature for another 2 minutes while it is boiling. (you will need to keep flicking the switch on) record your results

Time from switching on (minutes)

Temperature of water oC

012345678

Plot your results on a graph on the next page.

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TempoC

Time minutes

Graph of water temperature against time

Put the best word from the list in the spaces.

Water…………… are held together by weak forces when it is a liquid.

As the water heats up the water molecules in the liquid move around faster. The element in the jug supplies heat energy and the temperature rises. The………….. the temperature of the water the…………. the energy of the molecules and the faster they move.

At the boiling point of water the molecules have picked up enough………. to break free of each other and turn into steam. The……………. of water does not rise any further. This is known as the………….. point. The boiling point of water is 100oC.

Word list.Temperature, boiling, molecules, higher, energy, greater

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(3) What happens when liquids don’t mix?

Sometimes liquids don’t mix with each other and separate out into two layers.Oils don’t mix with waterThe molecules of water and oil are just too different to mix with each other.

What effect does soap have on oil and water? Try the experiment below but don’t do part F.

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Good scientists always keep careful notes of any observations they make during their experiments. Neatly record what you see on the table on the next page.

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Tube number List the chemicals in the tube

What did you see happen

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Soap breaks up oil and turns it into lots of small droplets that can mix with water.

Scientists call a mixture like this an emulsion. Examples of emulsions are milk, paint and moisturising cream.

Making moisturising cream, an emulsion

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