19. This device detects sound.  This device was invented in 1887.

Five clues about my sound object. 

1.  My device’s name is an acronym for Radio Detection & Ranging. 

2.  Heinrich Hertz invented this object.

3.  It is now mostly used for analyzing and predicting the weather.

4.  It has a radio transmitter and a receiver.

5.  It was used widely in World War II on ships and planes.

Ian        

20. The * reads the disk and puts the sound into the TV. The * produces sound.

Five clues about my sound object.

1. It stores data on one or both sides.

2. The format appeared in 1996.

3. It reads the disk with a laser.

4. It has more storage than a CD.

5. I picked this one because I have one at home.

Five clues about my sound object.

1.My sound device is a square kind of shape.

2.It has a button that can be turned off.

3. My device is made of an microphone and an amplifier, it also has one speaker.

4.You can use it at a building or at a school.