Grade 4 Science February Revision
Concept 3.1 & lesson 1 & 2 Concept 3.2
بفكركم أن المراجعة دي ليها فيديو شرح كل نقطة بالتفصيل ببساطة عشان يبقى كله سهل عليكم بإذن الله … و علشان تلاقى الفيديو اكتب فى اليوتيوب Dr.Rania Science و هيظهرلك كل حاجة .. او ابعتلى واتساب على رقمى 01029919557 هدخلك الجروب الخاص بيا و ابعتلك الفيديوهات ..بالتوفيق ليكم
و لو عايزين مراجعات MATHS و ICT بنفس الشكل ابعتولى على الواتس برضو
هنراجع دلوقتى الكونسيبت الاول فى الترم الثانى كامل يلا بيناااا و انت مشغل الفيديوووو
v Main points:
Ø The energy that comes in (Consumed by) a device is called “input energy“
Ø The energy that comes out (Produced by ) a device is called “output energy“.
Ø Battery stores (resource of) Chemical energy.
Ø Battery produce Electrical energy .
Ø Energy stored in food is Chemical Energy.
Ø Energy stored in Coal is Chemical Energy.
Ø Batteries inside the toys are the resource of chemical energy that is converted into electrical energy .
Ø When the batteries run out of charge, they can be recharged by connecting the device to a nearby charger or by replacing the old batteries with new ones.
Ø Mars is about 54 million km from Earth so the spacecraft takes 6 months.
Ø The “Mars rover Curiosity” is one of the most well-known of these robots which travels on the surface of Mars.
Ø The Curiosity exploration rover uses solar panels and batteries as a resource of energy.
Ø The solar panels on the rover convert solar energy into electrical energy, which is used to charge the rover’s batteries…… The electrical energy from the batteries charge the vehicle’s sensors and the electrical energy is also converted into kinetic energy and thermal energy.
Ø When you rub your hands, you will feel warm because kinetic energy is converted into thermal energy .
Ø Hair dryer converts Electrical energy into Thermal energy, kinetic energy and sound energy.
Ø Soap dispenser (Detergent bottle) converts Potential Energy into Kinetic Energy.
Ø Washing machine converts Electrical Energy into Kinetic Energy.
Ø Electric heater converts Electrical Energy into Thermal Energy.
Ø Electric bulb converts Electrical Energy into Light Energy and Thermal Energy.
Ø Flashlight converts Chemical Energy into Light Energy and Thermal Energy.
Ø Battery powered clock converts Chemical Energy into Kinetic energy.
Ø Hand bell converts Kinetic Energy into Sound Energy.
Ø Mobile phone مهمممم هتلاقيه تحت فى الصور
Ø Energy chain is a way to describe the energy flow that occurs when we use different devices
Ø Energy chains often start with the Sun .
Ø Electric wires are made of copper
Ø Most of the wasted energy leaks out in the form of heat.
Ø The law of conservation of energy : Energy can neither be created nor destroyed, but only converted from one form of energy into another .
Ø Wasted Energy does not help the device do its main function.
Ø Give reason for:
1. A remote-controlled toy car needs a battery to move from one place to another.
Because the chemical energy stored in battery is converted into electrical energy that changes into kinetic energy that makes the car moves.
2. Some calculators use the sunlight to operate.
Because the energy of sunlight (solar energy) is converted into electrical energy .
3. Mars rover Curiosity operates for a long period of time on Mars without
any need to be recharged.
Due to the presence of solar panels that use sunlight to recharge its batteries.
4. There is an energy change when you press the spring of a soap dispenser.
Because the potential energy stored in its spring is converted into kinetic energy
5. When you rub your hands together, you feel warm.
Because the kinetic energy is converted into thermal energy.
6. Not all the energy that enters the energy chain completely reaches the device.
Because some of the energy is wasted in the form of heat.
7. You feel heat, when you put your hands near a lighted electric lamp.
Because some of the electrical energy is converted into thermal energy.
8. The presence of batteries inside a toy car.
Because battery is the source of energy where the chemical energy is converted into electrical energy to operate the toy car.
9. Thermal energy in a mobile phone is considered as a wasted energy.
Because it doesn’t help the mobile phone to do its main function.
10. The electrical energy that enters the hair dryer does not come out of the hair dryer in the same form of energy.
Because it is converted into kinetic, thermal and sound energies.
11. Sound energy and thermal energy are considered as wasted energy in the blender.
Because they don’t help the blender to do its main function.
v What happens if:
1 1. If batteries of remote-controlled toy car run out.
The car will not move, so we can recharge its batteries by charger or replacing old batteries with new ones.
2. If solar calculators were exposed to the sunlight.
Solar energy is converted into electrical energy that operate them.
3. If Mars rover Curiosity didn’t get any sunlight on Mars surface.
It cannot be operated, because it depends on sunlight (solar energy) to recharge its batteries.
4.To the change of energy when you turn on the television.
The electrical energy is converted into sound energy and light energy.
5. To the change of energy when you burn a piece of wood.
The chemical energy is converted into thermal energy and light energy.
6. To the change of energy when you shake a small bell with your hand.
The kinetic energy is converted into sound energy.
7. If you put your hands near the lighted lamp.
You feel warm, because some electrical energy is converted into thermal energy,
8. If you use a mobile phone for a long time.(according to the wasted energy).
Some energy is wasted as thermal energy.
9. If you turn on an electric fan. (according to the change of energy).
The electrical energy is converted into kinetic energy which do the main
function of fan and sound energy as wasted energy.
Energy Chains
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