23
How does a telephone work?
Textbook Part 2, pp. 30–32
GoalUnderstand simply how a telephone works, know important numbers and rules for using phones.
New words
telephone · telefoncall · qo‘ng‘iroqsignal · signaltablet · planshet
Explanation
When we speak, a phone turns our voice into a signal and sends it through a tower to another phone. There the signal turns back into sound. We also use phones to take photos, watch films and send messages. To protect our eyes, we hold the phone at least an elbow’s length from our face and do not play games for long. In an emergency we call 101, 102 or 103.
Worked examples
I called Grandma and she heard my voice.
If someone gets ill, we call 103 — the ambulance.
Class activity
Experiment: poke a hole in the bottom of two paper cups and join them with a long string. Pull the string tight; one child speaks into a cup while the other listens. The sound travels along the string! A real phone also sends sound far away, but uses signals instead of string.
Practice
1
What is the ambulance number?
103
2
How far from your face should you hold a phone?
at least an elbow’s length
3
What else can a phone do?
take photos, send messages, watch films