Presentation on theme: "Science Revision Physical processes. Forces A push, pull, twist or turn acting on an object. What is a force? How many forces do you know?"— Presentation transcript:
Science Revision Physical processes
Forces A push, pull, twist or turn acting on an object. What is a force? How many forces do you know?
The force that causes all objects to be pulled towards Earth. Gravity exists between all objects in the universe. The downward force on an object caused by gravity. The force between 2 moving surfaces.
A force in water which pushes upwards The force that air exerts on a moving object The force that water exerts on a moving object
What might we use to measure forces? force meterWeighing scales When 2 forces are balanced there is no movement. Forces are measures in Newtons - do you know why?
Arrows show the direction the force is acting upthrust weight pull friction gravity Air resistance
Light What is light? A kind of energy that we can see All light comes from a source The glow produced by something hot
Light travels in straight lines and can be reflected
How do we see? When light enters our eye it travels along the optic nerve to our brain. The image is upside down but the brain turns it round.
Light can bend A prism can bend light and break it up into it’s colour spectrum A lens can also bend light which can help people to see better. Light source
What is a shadow? THIS IS NOT A REFLECTION A shadow is an area of darkness formed when an object blocks a light source so the shape of the object can be seen. Shadows will be different sizes at different times of the day early morningmid day
Sound How is sound made? Sound is a type of energy. A sound is made when an object causes the air around it to vibrate. These vibrations are called sound waves. What is the difference between noise and music? Noise is a series of random disorganised sounds. Music is a series of sounds that are organised into a pattern that has pitch and rhythm. This sounds pleasant to our ears.
The number of times a sound wave vibrates in one second is called it’s frequency
How are musical sounds made? blowinghitting plucking shaking scraping All of these methods cause air to vibrate.
How do we hear sounds? Sound waves enter the outer ear The sound travels along the ear canal to the ear drum The ear drum vibrates The sound passes through to the inner ear And to the brain
Electricity is the flow of energy or charge through a circuit What is a circuit? What is electricity? A system of wires and components connected to a battery or mains The power source in a circuit made up of two or more cells (about 1.5volts) What is a battery? What is mains electricity? Electricity from the main power supply or grid (about 240 volts)
Symbols Symbols are used to represents components in a circuit Do you know what these symbols represent? True or False? You can make a bulb brighter in a circuit by……….. Turning the battery/cell around Adding another battery Using a switch Using a more powerful battery
Electricity will not flow if there is a break in the circuit
Magnets Magnets have an invisible force around them called a…? The opposite ends of a magnet are called….? North Pole South Pole
If the poles of 2 magnets are put together 2 different things happen. The magnets either……………….? or each other repel attract Opposite poles attract. Alike poles repel.
Which materials are magnetic? MagneticNot Magnetic Steel nail Cotton reel One pound coin Paper clip brass nail pencil Aluminium drinks can
True False True If the forces on an object are equal, the object will not move. Upthrust is the opposite of friction. Friction is the force between moving surfaces. All light sources are natural. Light is made up of 5 different colours called the spectrum False Lenses are used to bend light Light can be reflected around corners. Gravity is a force which pulls objects towards the earth True True or False?
True False A shadow is caused by light reflecting off an object. Shadows get shorter as the sun gets higher in the sky. Sound is a type of energy. Sound cannot pass through solid objects. Sound is due the vibration of air or other material. Your ear drum vibrates to help the sound to travel. Sound and light travel at the same speed. Sound cannot travel in a vacuum (eg space) True
False True This is the symbol for a battery. Electricity is a flow of energy. If you add another battery to a circuit this will make a bulb brighter Electricity cannot flow if the circuit is broken. Closing a switch will break a circuit. All metals are magnetic. Opposite poles of a magnet repel each other. Mains electricity is very dangerous. True