Why Do We Have Time Zones? | A2 ESL Science Reading Passage

Use this A2-B1 ESL science reading passage to learn why we have time zones. It includes key vocabulary, reading comprehension questions, and answers for English learners.

Time zones help people set clocks as Earth rotates.

Reading Level

A2-B1

Word Count

186 words

Reading Passage

It can be morning in one country and night in another country. This happens because Earth is round and always moving. Different places face the Sun at different times.

Earth rotates once every day. When one side of Earth faces the Sun, that side has daylight. The other side is turned away from the Sun, so it has night. As Earth rotates, sunlight reaches new places.

A time zone helps people set clocks in a useful way. Places in the same time zone usually use the same time. Places far to the east or west may use different times because they see the Sun earlier or later.

This clock time is called local time. Local time helps people plan daily life. A school can start in the morning. A shop can open during the day. A family can know when to call someone in another country.

Time zones are also useful for travel, online classes, and world news. A globe can help us see why time changes from place to place.

We have time zones because Earth rotates, and different places receive sunlight at different times.

Earth's rotation makes different places receive sunlight at different times.

Key Vocabulary

Word	Meaning	Example
time zone	an area that uses the same clock time	Seoul and New York are in different time zones.
rotate	to turn around its own center	Earth rotates once each day.
sunlight	light from the Sun	Sunlight reaches different places at different times.
local time	the time used in a particular place	Local time helps people plan calls.
globe	a round model of Earth	A globe shows that Earth is round.

Reading Comprehension Questions

1. What does Earth do once every day?
2. Why can one place have day while another has night?
3. What is a time zone?
4. What is local time?
5. Why are time zones useful?

Answers

1. Earth rotates once every day.
2. One side of Earth faces the Sun while the other side is turned away.
3. A time zone is an area that uses the same clock time.
4. Local time is the time used in a particular place.
5. Time zones help people plan travel, calls, online classes, and daily life.

Short Summary

Time zones exist because Earth rotates. Different places receive sunlight at different times, so their clocks can show different local times.

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