Wave Properties
Yes or No
Do water waves push water from one place to another?
No, water waves transfer only energy from one place to another.
What is added together when two waves superimpose?
Amplitude
What component of a longitudinal sound wave is analogous to a trough of a transverse wave?
Rarefaction
Crest (peak) - compression
Earth's gravity (with a unit)
9.81 m/s2
How many science teachers do we have?
4
Give four characteristics of a wave
Amplitude, Period, Velocity (Speed), Frequency
_____________ is the bending of light at the junction of two media.
Refraction
A bat produces a sound at 17,250 Hz and wavelength 0.019 m. What is the speed of the sound?
17250 Hz x 0.019 m
= 327.75 m/s
If a 10 N force moves an object 3 meters, how much work is done? (With a unit)
In which country did Ms.Cha graduate from high school?
Thailand
Give three examples of transverse waves.
Light waves, water waves in a lake, seismic waves in Earth's surface (earthquake), waves on string, ...
Waves is reflected upright when _______________________ and waves reflected inverted when __________________________.
1. when a waved hits a surface or medium that is less dense (loose end)
2. when a wave hits a surface or medium that is denser (fixed end)
The compressibility of air and hydrogen is almost the same. What is the another factor that sound travels faster in hydrogen than in air?
Hydrogen is less dense than air.
What’s the difference between temperature and heat?
Temperature measures average kinetic energy, while heat is the amount of energy transferred due to temperature difference.
What is the Ms.Cha's wedding date?
March 3
If the horizontal distance, that is, the distance in the direction of propagation, between a crest and the adjacent trough of a sine wave is 1 m, what is the wavelength of the wave?
1 x 2 = 2m
Two identical waves superimpose in pure constructive interference. What is the height of the resultant wave if the amplitude of each of the waves is 1 m?
amplitude = 1 x 2 = 2m
--> height = 2 x 2 = 4m
The amplitude of sound wave ______________ with distance from its source because _________________________________.
1. decreases
2. the energy of the wave is spread over / some of the energy is lost in the form of thermal energy transferred to the air / energy is absorbed by objects.
Describe the first and the second law of thermodynamics.
2nd law: Entropy of the universe always increases.
List the topics of science fair/research project of each group.
Jenna/Esther - Density of materials vs. Sound decibel
Yoon/Yehoon - Frictional forces vs. Velocity/energy
Katelynn - Nuclear power as renewable energy
Oscar - Is time travel possible?
David - Nuclear Bomb
Neil - Electromagnetic fields and wireless charging efficiency
Why can light travel through outer space while sound cannot?
Sound waves are mechanical waves and require a medium to propagate. Light waves are nonmecahnical can travel through a vacuum.
Occasionally, during earthquakes, areas near the epicenter are not damaged while those farther away are damaged. Why could this event occur?
Constructive interference results in waves with greater amplitudes being formed in places farther away from the epicenter.
How is a human able to hear sounds?
Sound waves cause the eardrum to vibrate. A complicated mechanism converts the vibrations to nerve impulses, which are perceived by the person as sound.
Explain following formulas.
Q = mcΔT
Q = mLf
Q = mLv
Q = mcΔT - The amount of heat energy needed to change the temperature by 1oC/1K of a 1kg substance without changing its phase.
Q = mLf - The amount of heat energy needed to change between solid and liquid without changing its temperature.
Q = mLv - The amount of heat energy needed to change between liquid and gas without changing its temperature.
What’s the heaviest naturally occurring element?
Uranium