When do you arrive?

Liri floated restlessly back and forth at the window.

Liri: “I know now how far each jump is. But I don’t know how long a jump takes. When will I arrive at all?”
Erklärus: “For that you need a clock. Reading the time is like a second language – but one that you learn quickly.”

🕐 Reading an analogue clock

A clock has two hands: the short hour hand and the long minute hand. Between two numbers there are always 5 minutes.

12
1
3
5
6
7
9
11

The hour hand points exactly at the 3, the minute hand at the 12 → 3 o’clock (3:00).

When the minute hand points at the 6, half an hour has gone by (e.g. “half past three” = 3:30). When it points at the 3, it is quarter past, and at the 9 it is quarter to.

🕹️ Turn the minute hand yourself!

This time the hour hand stays at the 5. Drag the blue minute hand round the circle with the mouse (or your finger) – below you can see straight away what time it is.

12
1
3
5
6
7
9
11
5:00

🌗 The 24-hour day

A whole day has 24 hours – but the hour hand of a normal clock only goes up to 12. That is why it goes round twice: once for the hours 1–12 (morning/midday), once for 13–24 (afternoon/evening).

Erklärus: “15:00 is the same as 3 o’clock in the afternoon (3 pm). You simply subtract 12: 15 − 12 = 3.”
What time is 19:00 on a normal 12-hour clock?

⏳ Simple time intervals

Liri starts a jump at 14:00 and arrives at 17:00. How many hours did the jump last?

Erklärus: “Simply work it out: arrival minus start. 17 − 14 = 3. The jump lasted 3 hours.”
14:00 to 17:00 =
🌌 Time in the universe

The Moon takes about 27 days to orbit the Earth once.
A day on Mars lasts almost as long as on Earth: only 40 minutes longer.
Without clocks and time intervals, space missions could never plan exactly when a rocket should launch and when it should arrive.

❌ Common mistake

The minute hand is often mixed up with the hour hand – but the long hand is always the minute hand and the short one is the hour hand.

Tip: “big and fast” (minutes) versus “small and leisurely” (hours) – the long hand moves much faster!

🕐 Exercise 1 – Reading the clock
The hour hand points at the 6, the minute hand at the 12. What time is it?
o’clock
🌗 Exercise 2 – The 24-hour day
It is 22:00. What time does the normal clock show (with only 12 hours)?
⏳ Exercise 3 – Time interval
A jump starts at 9:00 and ends at 13:00. How many hours did it last?

A timetable home

For the first time, Liri drew a proper timetable: start at 14:00, arrival at 17:00, duration 3 hours.

Liri: “Now I don’t only know how far it is – I also know when I’ll arrive.”
Erklärus: “That turns a journey into a plan. And a plan turns into a home that you really reach.”
“Telling the time: short hand = hours, long hand = minutes. The 24-hour day goes twice round the 12-hour clock. Time interval = arrival minus start.”
What you learned today
17:00 − 14:00 = 3 hours
Short hand = hours · Long hand = minutes · Time interval = end − start
🌟

Chapter 11 mastered!

Liri can now read the clock and knows how long each jump home takes.

Erklärus’s notebook – page 11:
“Telling the time: short hand = hours, long hand = minutes, 5 minutes between two numbers. 24-hour day: subtract 12 for the normal clock. Time interval = arrival time minus start time.”
← Back to overview 11 – Telling the time