Waves, light and sound, Year 7: more practice：全部卡片
整套按顺序列出——孩子看到之前，您可以先通读一遍。
- Why do we see lightning before we hear the thunder?
Light travels much faster than sound
提示Compare the two speeds.
为什么Light travels at about 300 000 000 m/s, but sound travels at about 340 m/s in air.
- A ray of light hits a plane mirror with an angle of incidence of 35°. What is the angle of reflection in degrees? (number only)
35
提示The law of reflection.
为什么The angle of incidence equals the angle of reflection, measured from the normal.
- Why does a smooth mirror form a clear image while a rough wall does not?
The mirror reflects light in one direction
提示Compare how rays bounce off the two surfaces.
为什么A smooth surface reflects the rays in a regular way, but a rough surface scatters them in all directions.
- A struck tuning fork is touched on the surface of water and splashes appear. What does this show?
The fork is vibrating
提示What is happening to the prongs when it makes a sound?
为什么Sounds are made by vibrations. The splash shows the fork is moving quickly to and fro.
- Which part of a drum vibrates to make its sound?
The drum skin
提示It is the part you hit.
为什么Hitting the skin makes it vibrate, and it makes the nearby air vibrate.
- A string vibrates 1200 times in 6 seconds. What is its frequency in hertz? (number only)
200
提示Frequency is the number of vibrations per second.
为什么1200 ÷ 6 = 200 Hz.
- A guitar string is pressed so that the vibrating part is shorter. Does the note get higher or lower?
Higher
提示Think about which string vibrates faster.
为什么A shorter string vibrates faster, so its frequency is higher.
- Loudness of sound is measured in ____.
decibels
提示The unit is named after Alexander Graham Bell.
为什么Sound level, or loudness, is measured in decibels using a sound level meter.
- A drum is struck harder. What changes about the sound waves?
Their amplitude increases
提示Which property of a wave means the size of the vibration?
为什么A harder hit makes bigger vibrations, so a greater amplitude and a louder sound. The pitch stays the same.
- Sound usually travels fastest in solids and slowest in gases. Why?
The particles in a solid are closer together
提示Think about how vibrations pass from one particle to the next.
为什么Close-packed particles pass vibrations on to their neighbours more quickly than those far apart in a gas.
1★ KS3-PHYS-WAV-0036
2★ KS3-PHYS-WAV-0037
3★ KS3-PHYS-WAV-0038
4★ KS3-PHYS-WAV-0039
5★ KS3-PHYS-WAV-0040
6★ KS3-PHYS-WAV-0041
7★ KS3-PHYS-WAV-0042
8★ KS3-PHYS-WAV-0043
9★ KS3-PHYS-WAV-0044
10★ KS3-PHYS-WAV-0045