Timelines, Explorers & Great Inventions
PrimaryReading a timeline · brave voyages · big ideas that changed the world
Theory Key ideas
A timeline always reads in order: the earliest events on the left, the most recent on the right. Historians use two labels for dates: BCE ("Before the Common Era," counting backward toward zero) for very long ago, and CE ("Common Era," counting forward) for more recent times. A bigger BCE number is older, not more recent!
- Long, long agoPeople invent the wheel and writing — two of the most useful ideas ever.
- 1400s CEZheng He of China sails huge fleets across the Indian Ocean; soon after, Christopher Columbus and other European sailors cross the Atlantic Ocean.
- 1440s CEJohannes Gutenberg invents the printing press in Europe — books can now be made quickly instead of copied by hand.
- 1800s CESteam engines, trains and the light bulb transform daily life.
- 1900s–todayAirplanes, computers and the internet connect the whole world.
Explanation Why it matters
Explorers and inventors are exciting because they change what is possible. Before ships that could cross oceans, the peoples of the Americas, Europe, Africa and Asia barely knew each other existed. Before the printing press, only a few people could own a book. Each invention or voyage on this timeline didn't just add one new fact to history — it opened a door that let many other new things happen next, which is exactly what you'll see as this course continues.
Cause and effect. One event often causes another. The printing press (a cause) led to many more people learning to read (an effect) — and that effect became the cause of even bigger changes later.
Practical Build your own timeline of inventions
Think of five things you use nearly every day: for example, a phone, a car, a light switch, a book, a spoon.
Your turn: Draw a timeline and guess where each invention belongs — which do you think is oldest, which is newest? Then look up the real answer for one of them. Were you surprised by how old — or how new — it is?
Q&A Test yourself
How do you read a timeline?
From left to right — the earliest events are on the left, and events get more recent as you move to the right.
What do BCE and CE mean?
CE ("Common Era") counts years forward from a fixed starting point; BCE ("Before the Common Era") counts years backward before that point. A BCE year with a bigger number happened earlier, not later.
Why was the printing press such an important invention?
Before it, every book had to be copied out by hand, which took a long time and made books rare and expensive. The printing press could make many copies quickly, so far more people could own and read books — spreading ideas faster than ever before.
What does "cause and effect" mean in history?
It means one event (the cause) makes another event (the effect) happen. Historians look for these chains — for example, ocean-crossing ships (a cause) led to people from different continents meeting for the first time (an effect).
How the ideas connect
Every key idea in this chapter, branching from the core concept — use it to see the whole picture at a glance.
The key facts, visualised
Worked problems, step by step
Follow each solution line by line, then try to reproduce it on paper before moving on.
Example 1How do you build a timeline of inventions in the right order?
- Find the date each invention was made
- Put the earliest date on the left
- Space them out along a line to newest on the right
Example 2Why was the printing press such an important invention?
- Before it, books were copied slowly by hand
- The press printed many copies quickly
Now you try
Work each one out first, then tap to reveal the worked answer.