11/28 Observe the demonstration and complete the following: Write a statement explaining how you think the snare drum is being activated Did you use the word energy in your answer? An object at rest stays at rest unless acted on by an outside force – Newtons First Law of Motion

Will a barrier affect the drum noise?

–Distance –Frequency –Volume –Directionality of the source –Focusing the sound like using a megaphone What are some other factors may change the level of vibration in the drum?

Sound is produced when air is disturbed in some way. Sound travels as a compression, or longitudinal, wave. motion.htmlhttp:// motion.html Vibrations carry energy. Ocean waves are another kind of vibration that carries energy.

Sound energy can be absorbed or reflected. –Reflected by solid, flat surfaced –Absorbed by soft, porous materials

Vibrations in materials set up wavelike disturbances that spread away from the source

Light and Sound Similarities Something can be "seen" when light waves emitted or reflected by it enter the eye. Something can be "heard" when sound waves from it enter the ear. The snare drum models the way an eardrum senses sound waves.

Active vs. Passive Systems The effect of sound waves can be reduced through active and passive means. Passive – sound barriers and insulation systems can block and absorb noise Active – electronic and mechanical devices tuned to produce sounds that interfere with noise.

Interference The interaction between two or more simultaneous waves is called interference Constructive Interference

Interference The interaction between two or more simultaneous waves is called interference Destructive Interference

Interference Sines A and B have different frequencies. That means that their phase relationship constantly shifts with time: at one moment they are in phase and at another moment they are out of phase. Hearing BeatsBeats

Solving the noise problem What are some sources of noise pollution? –Traffic (also bad mufflers, loud car stereos…) –Air conditioners and fans –Construction –Water pumps for pools Some technological problems are best solved through experimentation. –Remember that Edison tried over 1000 filaments?

Invention is a process of turning ideas and imagination into devices and systems. Innovation is the process of modifying an existing product or system to improve it.

A decibel (dB) is a measure of sound intensity. The dB scale is logarithmic, meaning that a change of 10 dB represents a tenfold change in loudness. So, a sound measuring 30 dB is 10 times louder than a sound measuring 20 dB.

Sound Level Meters are used to measure dB level. Locations of sensing devices will affect the levels observed.

5/10 Answer in a complete sentence. Watch the 4 minute video clip. Write a statement describing how frequency affects the travel of sound over long distances.

12/5 Answer in a complete sentence. What strategies (reflection, absorption, or diffusion) is your group using in your noise reduction panel?

12/8 Answer in a sentence If we were to place you panel on the box backwards how do you think its performance would change? Why do you think this?

5/12 Answer in a sentence Identify a practical application for your noise reduction panel. –Where might it be used? –Who would use it?

12/6 Watch the short video and record information about the speed of sound.

Sound energy can be reflected, absorbed, diffused – sketch each Drill 11/30

12/1 Copy The parameters placed on the development of a system are called requirements. Requirements are made up of criteria and constraints