第 1 單元，第 1 課
Wave Properties波的性質
點卡片翻面。
1 / 20
- wave波A wave moved across the pond.
- vibration振動The guitar string’s vibration makes sound.
- mechanical wave力學波Sound is a mechanical wave.
- medium介質Air is the medium for most sounds we hear.
- transverse wave橫波Shaking a rope makes a transverse wave.
- crest波峰The surfer rode the crest.
- trough波谷The boat dipped into a trough.
- longitudinal wave縱波Pushing a spring toy makes a longitudinal wave.
- compression密部The speaker creates a compression in the air.
- rarefaction疏部A rarefaction follows each compression.
- sound wave聲波Sound waves cannot cross the vacuum of space.
- amplitude振幅A louder sound has a greater amplitude.
- loudness響度Loudness decreased as we walked away.
- intensity強度Sound intensity drops with distance.
- decibel分貝A jackhammer is about 130 decibels.
- wavelength波長Red light has a longer wavelength than blue light.
- frequency頻率The note has a frequency of 440 Hz.
- hertz赫茲Humans hear from about 20 to 20,000 hertz.
- pitch音調A shorter string has a higher pitch.
- ultrasound超聲波（超音波）Doctors use ultrasound to see a baby.
這課的重點字
- wave波
- vibration振動
- mechanical wave力學波
- medium介質
- transverse wave橫波
- crest波峰
- trough波谷
- longitudinal wave縱波