Does sound travel faster in water or air? Moving Sounds Developing: Illustrate a wave with labels Secure: Explain how sound is reflected and absorbed. Excelling: Create an instrument and explain how it works Entrance Activity Does sound travel faster in water or air? Key words amplitude energy frequency medium model particles pressure wave sound wave source vacuum

We can use sound energy to break a glass! Key Word Alert! Sound Wave Sound waves are created by the vibration of an object, which causes the air surrounding it to vibrate. The vibrating air then causes the human eardrum to vibrate, which the brain interprets as sound. We can use sound energy to break a glass!

How did the sound break the glass? Discussion Activity How did the sound break the glass? Extension Draw a diagram showing how a sound wave travels

Teacher Explanation Vibrating particles Sound is produced when particles of air or another medium vibrate and compress together. They move horizontally and have energy. These particles have so much energy that they can cause a glass to smash by hitting it. Sound is a type of longitudinal wave Slinky demo!

Longitudinal Waves Assessment Activity Complete the diagram of a longitudinal wave using the keywords. Rarefaction Wavelength Compression

Does sound travel faster in water or air? Moving Sounds Developing: Illustrate a wave with labels Secure: Explain how sound is reflected and absorbed. Excelling: Create an instrument and explain how it works Entrance Activity Does sound travel faster in water or air? Key words amplitude energy frequency medium model particles pressure wave sound wave source vacuum

Write down what you think happens when you hear an echo. Discussion Activity What is an echo? Extension Write down what you think happens when you hear an echo.

Teacher Explanation Sound Control A sound wave can be controlled in one of three different ways – it can be reflected, diffused or absorbed. Each of these reactions will depend entirely on the nature and composition of the material it comes into contact with, and each can be used to some extent in soundproofing. Controlling sound!

Match the definitions and diagrams! Assessment Activity Match the definitions and diagrams! Sound is bounced off a surface. This occurs on flat surfaces with a lot of mass like concrete or brick walls. Because the sound wave can't penetrate very far into the surface, the wave is turned back on itself. The sound bouncing back off the surface creates an echo. When a sound wave hits an irregular surface like foam or carpet, the vibration breaks up and travels along many much smaller paths. This divides the energy of the wave, sending it in many different directions which reduces its energy faster. When a sound wave hits a particular surface, the kinetic energy driving it is converted into a small amount of heat energy which dissipates, taking away power from the sound wave. This is sound insulation from things like foam and rubber.

Does sound travel faster in water or air? Moving Sounds Developing: Illustrate a wave with labels Secure: Explain how sound is reflected and absorbed. Excelling: Create an instrument and explain how it works Entrance Activity Does sound travel faster in water or air? Key words amplitude energy frequency medium model particles pressure wave sound wave source vacuum

Discussion Activity Making Instruments?

Explain your Kazoo Assessment Activity In your book write a paragraph explaining how a kazoo straw works and how it causes different sounds. Use keywords such as high, low, pitch, frequency, particles, medium and air!