SOLAR STILL

SOLAR STILL

SCIENCE EXPERIMENT

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QUESION

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SITUATION

QUESTION

ANY DOUBTS

ANSWER

PICTURE

WHAT I AM GOING TO PRESENT ABOUT

O1

SITUATION

A sailor runs out of drinking water in the middle of the sea. He cannot drink seawater directly to avoid dehydration

QUESTION

How can you help the sailor to obtain pure water from seawater?Based on your knowledge on condesation, create an experiment that can be done using only the items in your left hand side.

Info

• Pour the sea water into the container
• Place the glass in the middle of the container
• Cover the container with the plastic
• Place a rock in the middle of the plastic wrap on the top of the glass
• Let the container dry in the sun for an hour
• After a hour,drops of colourless liquid will form on the plastic package and drip in to the glass

answer

How does a solar still work? A solar still depends on two scientific principals: evaporation and condensation. By covering the top of the bowl with plastic wrap, we create a greenhouse effect. The heat of the sunlight gets into the bowl, and then the plastic traps the warmth inside. This warmth heats up the salt water and turns it to vapor (evaporation). Since water evaporates at a much lower temperature than salt, the salt is left behind in the bowl—when you take the cup of fresh water out of the solar still, look in the bowl and you can see the all the salt left. When the water vapor hits the plastic at the top of the bowl, it condenses and forms water droplets. Since we placed a weight over the cup, the plastic wrap slopes down. The water droplets follow the slope, and drip down into the cup.

question /answer

How can you prove that your experiment is sucess?Suggest one simple way.

Taste of the resulting liquid .If the liquid tastes sweet,then the liquid is pure and can be drunk

QUIZ

thanks