Early explorers

The video discusses the evolution of navigation techniques from the 15th to the 18th century. Initially, explorers used dead reckoning, a method based on previous positions, speed, and direction, to calculate longitude. This method was inaccurate, leading to the development of chronometers in the 18th century, which allowed explorers to determine longitude by comparing local time with the time at a known location, such as the Greenwich Observatory. Today, GPS technology provides precise navigation, but the spirit of adventure in sea exploration remains.

What was one of the main challenges explorers faced when discovering new lands in the 15th century?

• Finding fresh water

• Calculating their longitude

• Calculating their latitude

• Avoiding pirates

What method did sailors use in the 15th century to estimate their position at sea?

• GPS

• Dead reckoning

• Celestial navigation

• Radio signals

How did sailors measure the speed of their ship using dead reckoning?

• By counting knots on a rope

• By using a compass

• By observing the stars

• By checking the wind speed

What was a major limitation of the dead reckoning method?

• It was too expensive

• It could only be used during the day

• It was not very accurate

• It required advanced technology

How did chronometers improve the accuracy of navigation in the 18th century?

• By allowing sailors to measure wind speed

• By providing a map of the stars

• By predicting weather patterns

• By enabling comparison of local time with a known location