68
Why is sea water salty?
Textbook: Part 4, pp. 60–63
GoalGive general information on the Chinese folk tale “Dengiz suvi nega sho‘r?”; read an informational text on the benefit and harm of salt; compare a tale with a scientific explanation.
New words
salt · tuzgreed · ochko‘zliksea · dengizevaporation · bug‘lanish
Explanation
The textbook has a Chinese folk tale “Dengiz suvi nega sho‘r?” (Why is sea water salty?), which treats kindness and greed and explains the salt of the sea. We do not retell it. A tale and science do not give the same answer. The scientific explanation: rivers carry salts dissolved from rocks into the sea, the sun evaporates the water and the salt stays in the sea. Salt is necessary for our body, but too much harms health; it is advised to eat no more than about a teaspoon a day in total. If there is too much salt in the soil, plants do not grow well.
Worked examples
Text “Sea salt”. Rivers flow from mountains, carrying a very small amount of salt with them. When this water flows into the sea, the sun’s heat evaporates a part of the water. The salt does not evaporate; it stays in the sea. Over thousands of years the water became saltier. People dry sea water to get salt. Table salt gives taste to food, but must be used in moderation.
Comparison: a tale shows an idea; science explains the cause.
Class activity
“Tale and science”: children fill a two-column table with the difference between tale and scientific explanation.
Practice
1
What do rivers carry to the sea?
A small amount of dissolved salt
2
How does the sun affect water?
It evaporates it.
3
Why does salt remain in the sea?
It does not evaporate.
4
What does eating too much salt do?
Harms health.
5
To which people does the tale belong?
The Chinese people