🌡️ Torricelli and His Mercury Barometer
👨🔬 Who was Evangelista Torricelli?
Evangelista Torricelli was an Italian scientist and mathematician. In 1643, he became the first to show that air has weight and exerts pressure. He invented the mercury barometer, which measures atmospheric pressure.
🧪 Construction of Torricelli’s Barometer
Torricelli filled a long glass tube (about 1 meter), closed at one end, with mercury. He sealed the open end and inverted the tube into a dish filled with mercury.
- A 1-meter long glass tube (sealed at one end)
- Completely filled with mercury
- Inverted over a dish (reservoir) containing mercury
⚙️ Working Principle
When inverted, some mercury flowed out of the tube. The rest stayed up due to air pressure on the mercury in the dish. The empty space above is called a Torricellian vacuum.
- Mercury remains suspended due to atmospheric pressure
- The typical height is 76 cm (or 760 mm) at sea level
- The higher the air pressure, the taller the mercury column
✅ Advantages of Torricelli’s Barometer
- Simple to construct
- Accurate measurement of atmospheric pressure
- No power needed to operate
- Laid the foundation for weather instruments
❌ Disadvantages
- Mercury is toxic
- Device is long and fragile
- Not portable
- Affected by temperature and viewing angle (parallax)
🎯 Try These Puzzles!
🔍 Puzzle 1:
Who invented the mercury barometer?
🔍 Puzzle 2:
What liquid is used in Torricelli’s barometer?
🔍 Puzzle 3:
What is the space above the mercury column in the tube called?
🔍 Puzzle 4:
If atmospheric pressure increases, what happens to the mercury level?
🔍 Puzzle 5:
What does a falling mercury column in a barometer indicate?
🔍 Puzzle 6:
Why is mercury preferred over water in barometers?
🔍 Puzzle 7:
Convert 760 mmHg to Pascal (use 1 mmHg = 133.3 Pa)
🔍 Puzzle 8:
Why must the tube be closed at one end in Torricelli's barometer?
