Year 9 Science · Unit 4 · Lesson 5
Apply Worksheet
Learning Goals
Odd one out
Circle the item that does not belong in each group. Then explain why it doesn't fit in the answer column.
| # | Group | Your answer (odd one + reason) |
|---|---|---|
| 1 | Sound Seismic P-wave Water surface wave Radio wave | |
| 2 | Crest Trough Rarefaction Amplitude | |
| 3 | Hertz Metres Seconds Metres per second | |
| 4 | Frequency doubles Wavelength halves Speed doubles Speed stays constant |
Real-world context
Seismologists at Geoscience Australia monitor earthquakes using two types of seismic waves. P-waves (primary waves) travel at 6,000 m/s and have a frequency of 2 Hz. S-waves (secondary waves) travel at 3,500 m/s. During a 2023 earthquake off the coast of New South Wales, the P-waves arrived at the monitoring station 8 minutes before the S-waves.
(a) Calculate the wavelength of the P-waves. Use v = 6,000 m/s and f = 2 Hz. Show your working.
(b) Identify whether P-waves are transverse or longitudinal waves, and give a reason for your answer.
(c) Explain why P-waves arrive at the monitoring station before S-waves. In your answer, refer to the wave speeds given above.
1. A student states: "Amplitude and frequency both affect how loud a sound seems." Evaluate this statement. Which part is correct and which is incorrect? Use correct scientific terms.
2. Light from the Sun travels 1.5 × 10¹¹ m to Earth in approximately 8 minutes. Calculate the speed of light using speed = distance ÷ time. (Hint: convert 8 minutes to seconds first.) Show your working.
Wrap Up
In one sentence, what was the main idea of this lesson?