Sound vs Light Starter How can we use

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Sound vs Light Starter: How can we use light for communication?

Sound vs Light Starter: How can we use light for communication?

Sound vs Light Objectives: • Recall that sound and light are used for communication

Sound vs Light Objectives: • Recall that sound and light are used for communication (L 4) • Understand sound is a form of energy and requires a medium to transfer it (L 5) • Explain why sound travels at different speeds through different mediums (L 6)

• Sound waves transfer energy to our ears and light waves transfer energy

• Sound waves transfer energy to our ears and light waves transfer energy to our eyes • Sound waves can only transfer energy through a medium • Light however can transfer its energy without the presence of a substance

What happens when the air is removed from the bell-jar? Sound waves are vibrations

What happens when the air is removed from the bell-jar? Sound waves are vibrations and so need a substance to travel through. With air inside, the sound can be heard. With nothing inside [a vacuum], the sound can’t be heard.

Sound travels by particles vibrating. To understand this better you need to remember what

Sound travels by particles vibrating. To understand this better you need to remember what the particles look like in a solid, liquid and a gas: solid liquid gas Which state does sound travel fastest through? Why?

Sound waves need particles in order to travel. Speed of sound [m/s] The

Sound waves need particles in order to travel. Speed of sound [m/s] The substance that the sound travels through affects the speed of sound greatly.

• Rabbits warn each other of danger by thumping the ground. • Explain

• Rabbits warn each other of danger by thumping the ground. • Explain why this is more effective than ‘crying’ a warning.

Sound : How fast does it travel? Most of us have seen thunder storms

Sound : How fast does it travel? Most of us have seen thunder storms - which comes first, the thunder or lightning? The lightning gets to our eyes before thunder reaches our ears. 1) Thunder & lightning are made at the same time so we deduce that light travels much faster than sound. 2) In fact light travels so fast that: the time between seeing the flash and hearing the bang = time taken for sound to travel.

Sound : How fast does it travel? STOP START > 100 m 1) When

Sound : How fast does it travel? STOP START > 100 m 1) When you see the cymbals crash, press START. 2) When you hear the cymbals crash, press STOP.

Task: • Create an instruction booklet for novicespies on how to communicate using light

Task: • Create an instruction booklet for novicespies on how to communicate using light and sound OR • A script for a children’s television programme about sound and light

Sound vs Light Objectives: • Recall that sound and light are used for communication

Sound vs Light Objectives: • Recall that sound and light are used for communication (L 4) • Understand sound is a form of energy and requires a medium to transfer it (L 5) • Explain why sound travels at different speeds through different mediums (L 6)

Plenary: • Can travel through glass • Given out by a firework • Used

Plenary: • Can travel through glass • Given out by a firework • Used by bats to navigate • Fastest in a solid • Fastest speed possible • Can travel through a vacuum • A form of energy • Caused by a vibration • Used for communicating