World history: trade networks and exchange (grade 10) · lesson

The Silk Road and the Indian Ocean

💡 Routes that carried goods also carried ideas, religions, and germs.

The Silk Road was a web of land routes linking China to the Mediterranean. Merchants traded silk and spices, but travelers also carried religions like Buddhism, inventions, and languages.

In the Indian Ocean, sailors used the monsoon winds. These winds change direction with the seasons. Ships sailed out on one monsoon and waited for the winds to reverse to sail home.

Trade routes could also spread disease. In the 1340s, the Black Death moved from Asia to Europe along sea and land routes, carried by fleas and rats traveling with merchants. Trade slowed afterward, but it recovered.

🧠 How to think about it

When something spreads far and fast, trace who was traveling. If merchants traveled the route, their goods, beliefs, and germs all traveled with them.

monsoon: a seasonal wind that changes direction during the year
caravan: a group of traders traveling together

Trade across the Sahara

💡 Camels made the Sahara crossable, and control of the gold and salt trade made Mali rich.

Crossing the Sahara meant days without water. Camels could carry heavy loads and go a long time without drinking, so caravans of camels carried goods across the desert.

West Africa had gold, and the Sahara had salt. The empire of Mali controlled the routes between them and grew rich. In 1324, Mali's ruler Mansa Musa traveled to Mecca and gave away so much gold that people talked about Mali's wealth for years.

🧠 Let's work it out

Ask what made a trip hard and what solved it.
A desert lacks water, so an animal that needs little water is the key.
Then ask who controlled the route, because whoever controls a busy route can grow rich from it.

What do you think comes next?

trans-Saharan: across the Sahara Desert

The Columbian Exchange

💡 After 1492, crops, animals, and germs crossed the Atlantic in both directions and changed life on every continent.

The Columbian Exchange was the movement of plants, animals, and diseases between the Americas and the rest of the world after 1492. Potatoes, corn, and tomatoes first grew in the Americas and went east. Wheat, horses, and cattle went west.

The potato gives many calories per acre and grows in poor soil. Families in parts of Europe could feed more people from less land, which helped populations grow in the 1700s.

Horses changed life on the Great Plains. Mounted hunters could follow bison herds, and people could travel and trade much farther.

Diseases like smallpox were new to the Americas. Europeans and Africans had lived with these germs for centuries, but Indigenous people had no immunity. Epidemics killed a very large share of them, mostly without anyone planning it.

🧠 Let's work it out

To track an exchange, ask where each item started.
Then it must have moved away from there.
To explain an effect, ask what the new item let people do, such as feed more people per acre or hunt faster.

What do you think comes next?

immunity: the body's ability to resist a disease it has met before
epidemic: a disease that spreads quickly to many people

Sea routes and global trade

💡 By the 1500s, ocean routes tied the Americas, Europe, Africa, and Asia into one global trade network.

Asian spices once reached Europe through many traders, and each one added to the price. Portugal wanted a direct sea route. In 1498, Vasco da Gama reached India by sailing around Africa, so Portuguese merchants could buy spices at the source.

Key voyages came close together: Columbus reached the Americas in 1492, da Gama reached India in 1498, and Magellan's expedition finished the first trip around the world in 1522.

Spain mined huge amounts of silver in the Americas, at places like Potosí. Much of it crossed the Pacific on Spanish ships to Manila and was used to buy Chinese goods. Silver from the Americas ending up in China shows trade had become truly global.

🧠 Let's work it out

Follow the money.
Each middleman takes a cut, so a direct route means more profit.
Then trace one good, like silver, from where it was dug to where it was spent.

What do you think comes next?

middleman: a trader who buys from one person and sells to another