الأسبوع 10 · المحور الثاني «المادة والطاقة»، الوحدة الثانية «الحركة»: ابدأ، المفهوم 2.1 «الحركة والتوقف» (أ): القوى التي تحرك الأجسام · 3 دروس
1
Cars, trucks and planes: what makes them go?
Discovery Education Science P4: Term 1, Unit 2, pp. 116–129
GoalExplain what makes vehicles start moving and stop, and write questions about motion.
New words
motion · when something changes its placeengine · a machine that makes a vehicle movebrake · a part that slows or stops a vehicle
Explanation
Motion is all around us: cars on the road, a train to Aswan, a jet in the sky. Nothing starts to move by itself. A truck moves when its engine turns the wheels, and the wheels push against the road. A jet plane moves when its engines push hot gases backward and the plane is pushed forward. To slow a truck, the driver presses the brakes, which press on the wheels and slow them. To stop a plane after landing, brakes and other parts work together. So to start, change or stop motion, a push or a pull is needed. Engineers study how vehicles move and stop in order to make roads and travel safer. Later in this unit we will design ideas for vehicle safety. Now write questions: How does a jet plane start moving? What makes a truck stop? What do I already know about motion?
engine works→wheels turn and push the road→truck moves forward
Worked examples
A truck driver starts the engine. The wheels turn and push against the road, and the truck moves forward. The engine does the work of starting the motion.
A bus driver sees a red light and presses the brake pedal. The brakes slow the wheels and the bus stops smoothly at the line.
A plane at Cairo airport starts its engines. They push hot gas backward and the plane moves forward along the runway. We can write questions: How fast does it go? How does it stop after landing?
Class activity
Know, Want, Learned. Make a three-column chart. In “What I know” write three things that move and what makes them move. In “What I want to know” write two questions about starting or stopping. After the unit, fill “What I learned”. Show the chart to a grown-up and ask what they know about brakes.
Practice
1
What makes a truck start to move?
Its engine turns the wheels, and the wheels push against the road.
2
What do brakes do?
They slow down or stop the wheels and so the vehicle.
3
A parked car does not move by itself. Why?
There is no push or pull to start it.
4
Write one good question about motion.
Answers differ, for example: How does a jet plane stop after landing?
