waves

oscillations - Mechanische Schwingungen

experiment - pendulum - Fadenpendel

• what can you measure?
• 20cm and 40cm string?
• count n in 10, 20, 30 seconds.

period T- Schwingungsdauer T

$${T = \frac{t}{n}}$$

${t}$ - time in seconds and ${n}$ - number of oscillations.

frequency - Frequenz

$${f = \frac{n}{t} = \frac{1}{T}}$$ in ${s^{-1}= 1 Hz (Hertz)}$

amplitude - Amplitude

• minimum and maximum

equilibrium position - Nulllage

displacement - Auslenkung

distance from the equilibrium position at a given time t.

IB book - ${x(t)}$

German text book - ${y(t)}$

wavelength - Wellenlänge

The length of a wave in metres is called ${\lambda}$.

velocity of wave - Geschwindigkeit

$${v = \lambda \cdot f}$$

sine curve - Sinuskurve

$${y(t) = A \cdot \sin{\left(\frac{2\pi \cdot t}{T}\right)} }$$

${A}$ is the amplitude.

${T}$ is the period.

${y(t)}$ is the vertical displacement in this case. (books will have different notations)

Note - There is no phase shift in this applet.

simple harmonic motion (SHM) - harmonische Schwingung

spring

linear force - lineares Kraftgesetz

Rückstellkraft

spring constant k - Proportionalitätsfaktor D (see Hooke’s law)

m - mass (Masse)

period ${T = 2\pi\sqrt{\frac{m}{D}}}$

Hooke’s law

$${D = \frac{F}{s}}$$

or

$${k = \frac{F}{s}}$$

sound

experiment - oscilloscope

online oscilloscope virtual oscilloscope

objectives

1. Recall that all waves transfer energy from one point to another
2. Understand that in a longitudinal wave the particle vibrations are parallel to the direction in which the wave is travelling
3. State two examples of longitudinal waves
4. Understand that in a transverse wave the particle vibrations are perpendicular to the direction of travel of the wave
5. State two examples of transverse waves
6. Define the Amplitude, Frequency, Speed and Wavelength of a wave

wave equation

7. Recall the wave equation: $${v = f \times \lambda}$$
8. Rearrange this formula and use it to solve problems

reflection

9. Use wavefront diagrams to illustrate the reflection of waves
10. Recall that for reflection from a plane boundary the angle of incidence equals the angle of reflection
11. Recall that for reflection of waves, the speed, frequency and wavelength of the waves does not change

refraction

12. Understand what is meant by the term refraction
13. Use wavefront diagrams to explain the refraction of waves
14. Recall what happens to the speed, wavelength and frequency of waves during refraction

diffraction

15. Understand what is meant by the term diffraction.
16. Understand what is meant by the term wave interference.
17. Use wavefront diagrams to explain constructive and destructive interference.
18. Understand simple harmonic motion of either a simple pendulum or a spring.
19. Understand the terms wave resonance and harmonics.
20. Apply your understanding of resonance to musical instruments.

sound