Answer:

1.Cover one ear. Hold the clock 5cm away from your ear. Can you hear the clock ticking?

No you can't hear the clock ticking

2. Place the water-filled ballon againts your ear. Hold the clock againts the ballon. Can you hear the clock ticking?

Yes you can hear the clock ticking

3.Place your ear againts a wooden door and the clock on the other side while covering your other ear. Can you hear the clock ticking?

Yes you can hear the clock ticking