الصف الرابع الابتدائي ساينس
ساينس رابعة ابتدائي

لينك تحميل الملزمة
https://drive.google.com/file/d/1SPNXSms8RxOnjhne7a9hcg_mj5EAFWgf/view?usp=sharing

لينك تليجرام
https://t.me/mrahmedelbashagroup

In This Video :
- We have learned in the previous lessons that the large rocks are broken down into smaller particles during weathering process.
- Once the rock has been broken, it is ready for erosion.

Erosion
It is the process in which the small particles (sediments) of sand, soil and rocks are moved to other places by wind, water and gravity.

Action of wind erosion:
• A gentle wind may carry sand grains for a short distance (about 1 meter), while stronger wind and hurricanes carry them for a longer distance.

Action of water erosion:
• Rivers and floods carry sand, soil and rocks downstream.
• Sea waves pull sand away from beaches.
• Rain washes away the soil of farms that locate beside downhill.

Deposition
It is the process of laying down of sediments after its erosion.

Action of water in deposition:
- Running water in rivers play an important role in deposition process such as:
•A river can deposit a sandbar along its banks (sides).
•When a river carries sediments meet a sea, these sediments are deposited there forming a delta such as the Nile Delta.

Delta:
It is a fan-shaped (triangle-shaped) mass of mud and other sediments that forms where a river enters a large body of water.



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