This key facts covers Ultrasound Applications within Sound Waves for GCSE Physics. Revise Sound Waves in Waves for GCSE Physics with 13 exam-style questions and 15 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 5 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
🦇 Ultrasound Applications
Medical imaging (pre-natal scans):
- Ultrasound pulses sent into body
- Reflects off tissue boundaries (where density changes)
- Time and intensity of echoes used to build up an image
- Non-ionising — safer than X-rays for developing babies
Industrial testing (SONAR):
- Finding cracks/flaws in metal structures
- Measuring thickness of materials
- Submarines/ships use SONAR to detect objects under water
Echo calculations:
distance = speed × time ÷ 2 (divide by 2 because sound travels THERE and BACK)
Quick Check: An ultrasound pulse takes 0.004 s to return after being reflected from a foetus. The speed of sound in tissue is 1500 m/s. How far away is the foetus?
distance = (speed × time) ÷ 2 = (1500 × 0.004) ÷ 2 = 6 ÷ 2 = 3 m. Wait — that seems too large. Let's recheck: (1500 × 0.004) = 6 m total path, so distance = 6 ÷ 2 = 3 m. For a realistic prenatal scan, the pulse travel time would typically be microseconds, not milliseconds. But using these numbers: distance = 3 m.
Practice questions for Sound Waves
What type of wave is sound?
Describe how a sound wave is produced and how energy is transferred by a longitudinal wave.