Wave Interactions
How are echoes produced?
Echoes are produced by reflected sound waves
A pencil in water appears broken due to which wave interaction
Refraction
Reflection
The BOUNCING back of a wave after it strikes a barrier or object
What two factors does the amount of diff reaction depend on.
The amount of diffraction depends on the wavelength of the waves and the size of the barrier or opening.
What does the law of reflection state?
The angle of incidence equals the angle of reflection
Diffraction
The bending of a wave around a barrier or through an opening
Scientific Method Review: The speed of a chemical reaction depends on a number of factors, including the concentration of the chemical reactants and the temperature at which they are combined. In an experiment studying a particular chemical reaction, the temperature is increased by 5 degrees each time the reaction is performed. 1. Identify the IV 2. Identify the DV 3. Identify 2 variables that remain constant.
1. IV: the temperature (the ONE factor that is deliberately changed) 2. DV: the speed of the chemical reaction (varible being measured in the experiement) 3. Constants: type of chemical reaction and the concentration of each reactant
If a wave strikes a barrier at an angle of 33 degrees with the normal, at what angle will the wave leave the barrier?
33 degrees (Angle of incidence = Angle of reflection)
Scientific Method Review: What are constants?
Constants are variables in an experiment that remain exactly the same in the control and experimental groups.
Describe what happens during constructive interference.
Constructive interference occurs when the crests of two waves overlap (and the troughs of two waves overlap) The result is a LARGER wave -- deeper troughs and higher crests than the original waves
Describe what happens during destructive interference.
Destructive interference occurs when the crests of one wave overlap with the troughs of another wave. The result is a SMALLER wave.
True or False: Light waves diffract more than sound waves.
False! Sound diffracts easily around the edges of objects. Light does NOT diffract much around the edges of objects.
True or False: Only light waves reflect.
False: All waves (sound, light, water waves) can be reflected
Incident wave
Incoming wave (Wave that is striking a boundary)
The speed of a wave is determined by the properties of the _______.
Medium (different medium different speed & different temp within the same medium results in different speeds)
Which wave interaction produces moonlight?
Moonlight is produced when light from the sun reflects off the moon
Reflected wave
Outgoing wave (The wave that bounces off the surface of an object or boundary)
Which wave interaction produces rainbows?
Rainbows are produced when light refracts (bends) as it travels from air into droplets of water.
All waves change speed when they enter a new medium but they don't always bend. Explain when bending occurs.
The bending of a wave (refraction) occurs when a wave enters a new medium at an angle. If a wave enters a new medium perpendicular to the surface, it will NOT refract.
Refraction
The bending of a wave as it passes at an ANGLE from one medium to another
Scientific Method Review: What is the purpose of a control group?
The control group serves as a standard for comparision. It typically lacks the factor being tested.
Scientific Method Review: What is the dependent variable (DV)?
The dependent variable is the variable that is MEASURED during the experiment. It is the DATA that is collected. (The scientists is trying to determine how changes in the IV affect the DV.)
Scientific Method Review: What is the independent variable (IV)?
The independent variable is the ONE variable that is DELIBERATELY or PURPOSEFULLY changed by the scientist. It is the factor being tested.
True or False: Seeing an object is a result of reflection.
True! In order to see something light has to reflect off an object. Without light you could not see the object.
True or False: You can hear around corners due to the diffraction of sound waves
True! Sound waves diffract easily around barriers or the edges of objects
interference
a wave interaction that occurs when two or more waves overlap
Wave amplitude [increases or decreases] during constructive interference.
increases
