Final answer:
The two kids are using sound wave transmission through the milk tins as their communication technology. The quality of the signals may not be very good due to factors such as background noise and the materials used. They are using acoustic or mechanical communication.
Step-by-step explanation:
The principle behind the communication technology used by the two kids with the milk tins is called sound wave transmission. When one child speaks into the tin, their voice causes the bottom of the tin to vibrate.
These vibrations travel through the string or wire connecting the tins and cause the bottom of the receiving tin to vibrate as well. This vibration is then converted back into sound waves, allowing the other child to hear the message.
The quality of the signals transmitted through the milk tins may not be very good. This is because the sound waves can be easily disrupted by external factors such as background noise or obstacles in the path of the vibrating string or wire.
The longer the wire or string, the more the sound waves get attenuated. Additionally, the tin cans themselves may not be good at transmitting sound waves accurately, leading to a loss of signal quality.
The kids are using a simple form of communication technology known as acoustic or mechanical communication. This type of communication relies on the transmission of sound waves through a medium, in this case, the string or wire connecting the tin cans.
Acoustic communication does not require any external devices or electricity, making it a low-cost and easily accessible form of communication.