شرح ساينس الصف السادس الابتدائي لغات - الفصل الدراسي الثاني
شرح ساينس سادسة ابتدائي - ترم ثاني

لينك تحميل الملزمة
https://drive.google.com/file/d/1n4Qzq_iWpsK-F5ceOvgphYQxaI7cYSQD/view?usp=sharing

لينك تليجرام
https://t.me/mrahmedelbashagroup

In This Lesson:
Water cycle
It is the continuous movement of water among different water reservoirs.
Water reservoirs
They are storage locations of water on Earth.

Water reservoirs include:
- Oceans. - Seas. - Lakes.
- Rivers. - Glaciers. - Soil.
- Rocks. - Living organisms. - Atmosphere.
▌The main processes and steps that move water among these reservoirs are evaporation, condensation, precipitation, runoff and collection.
▌All these processes and steps depend on energy and force.

Energy:
▌The Sun is the most important source of energy that affects the water cycle.
▌The sunlight (solar radiation) that comes from the Sun includes thermal energy that causes the change of the state of water through the water cycle, where :
- When water changes from solid state (ice) to liquid state (liquid water), it gains energy.
- When water changes from liquid state (liquid water) to solid state (ice), it loses energy.

Force:
▌Water starts to move or change its way of movement when a force affects it.
▌There is a main force that affects the water cycle, which is gravity.

Gravity:
• It is the force that causes:
- Falling of melting ice crystals and water droplets found in clouds back to the Earth's surface.
- This leads to flowing of liquid water downhill into streams and rivers towards larger water bodies.

Flowing of water in solid state (ice) in glaciers from higher altitude areas (higher elevation) to lower altitude areas (lower elevation), where the frozen water melts and flows into the ground or the water bodies.

- Leakage of liquid water down into the ground then to groundwater reservoirs.
- Flowing of groundwater from higher altitude areas to lower altitude areas.

Energy and Water
Energy and the water cycle:
▌From the previous activities, you have known that when water changes from one state to another, it gains (absorbs) or losses (releases) energy.
▌Gaining or losing energy affects the water particles (molecules) in the air.
▌The movement of air from one place to another in the presence of difference in temperature leads to:
- Changing liquid water to water vapor and this process is known as "evaporation".
- Changing of water vapor to liquid water (in the form of water droplets) and this
process is known as "condensation".

Transfer of energy:
▌Condensation and freezing are two processes occur when water particles lose thermal energy.
▌Melting, evaporation and transpiration (in plant leaves) are processes occur when water particles gain thermal energy.

Evaporation:
▌Through the water cycle, the Sun heats water in oceans, seas, lakes, rivers, streams and other
water bodies.
▌This leads to evaporation of water and changing it into water vapor due to gaining thermal energy.

Transpiration:

• About 10% of water vapor in the air comes from transpiration of plants.


Example shows transpiration:
1. Bring two plants differ in size.

2. Put one of them in the direct sunlight and the other in shadow area.

3. Tie around a leaf from each plant a plastic bag .

What do you notice:
• Water droplets formed inside each of the two bags.
• The sunlight affects the amount of transpiration of plants, where when the amount of the
energy comes from the Sun increases, the transpiration in plant's leaves increases.
Condensation:
Condensation occurs when:
• The air that is saturated with water vapor cools due to decreasing air temperature, so the water vapor changes into liquid water.
• Clouds are formed, where they consist of tiny water droplets that are condensed in the air, so water vapor releases its energy and changes into liquid water.


بالتوفيق
مستر احمد الباشا