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H»s«piw V. Experiment tlme

In tliis chapter you will learn about

•    salt water

•    water pressure

SALT WATER

© One of the most important facts abóut the water in the oceans and seas is that it is sal ty. 97 % of the water on Planet Earth is salt water. The average salt content is 3.5 % but this changes ac-cording to temperaturę, Warm seas are saltier than colder ones.

Discuss why.

Most of the salt comes frorn the roclcs of the Coastal regions.

Describe the process shown In the drawing.

The salt water experiment

You will need:

« a glass haif fuli of water - an egg

° 5 teaspoonfuls of salt

© Follow the instructionś:    *

° Put the egg in the glass of water. What happens?

•Taks the egg out of the glass.

» Put 5 teaspoonfuls of salt in the water, stir well and wait a few minutes. ° Put the egg in the water again. What happens this time?

© Now write up the experiment.

First tick the correct answers on the following page, then write up a short experi-ment report. Think up your own conclusion.

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Instructions	Descriptłon
Put the egg in the glass of water.	We put the egg in a glass of water. □    It floated. □    It sank slowly to the bottom. □    It floated for a while then it sank.
Take the egg out of the glass.	We took the egg out of the glass.
Put 5 teaspoonfuls of salt in the water,	Then we put 5 teaspoonfuls of salt
stir well and wait a few minutes.	In the water. We stirred it and waited a few minutes. □    The salt swam on the surface of the water. □    The salt dissolved in the water. □    The salt sank to the bottom of the
	glass.
Put the egg in the water again.	After that we put the egg in the water again. □    This tlme it floated. □    This time it sank to the bottom.

Datę:.

The salt water experlinent

l/Ve puf the egg in a glass of water.

Conclusion:

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