The Amazing World of Gravity - Introduction (01:40)
Gravity affects many aspects of our everyday lives, such as weight and height. Physicist Jim Al-Khalili introduces the idea and experiments that can be done with gravity.
There are many complex elements to gravity but they are all contained in the principle of how objects fall. Al-Khalili explains the importance of air resistance and acceleration, which was discovered by Galileo.
Detecting Gravity (02:55)
Al-Khalili visits the Space Geodesy Facility, where scientists are measuring the strength of gravity using a gravity meter. An object is dropped inside a vacuum and is measured using a laser. The strength of gravity changes at a certain spot over time.
Weakest Point of Gravity (03:28)
Two people are searching for the place in Britain where gravity is the weakest. They are being accompanied by a team of scientists, who will take measurements at each possible site.
Mass and Weight (03:30)
Finding the weakest point of gravity depends on understanding the difference between mass and weight. Mass is fixed while weight is the effect of gravity on an object. The team is carrying a two kilo mass to see if its weight changes at different locations.
Newton's Law of Gravity (03:57)
Altitude also affects gravity, which is a concept discovered by Isaac Newton. Newton's equation for gravity can apply to any object in the universe. Al-Khalili explains how Newton's law is still used today.
Farther Point (04:43)
The team looking for the weakest point of gravity in Britain travels to a place higher than the tallest mountain. Using Newton’s law of gravity, they must be as far away from the Earth's core as possible.
Varying Latitude (03:27)
The team travels south to see how latitude affects gravity. They find that gravity is the same at sea level and the top of a mountain. They search for a place with low latitude and high altitude to increase their distance from the Earth's core.
Mass of the Earth (04:23)
British scientist Henry Cavendish conducted an experiment to find the mass of the Earth and fill in the unknown variable in Newton's equation. He built a torsion balance to measure gravitational pull of spheres and determines the Earth's mass.
Daily Effects of Gravity (02:45)
Gravity pulls people down through the course of the day, making them taller in the morning than at night. A researcher has been studying how gravity affects the health and fitness of humans.
Latitude and Altitude (05:50)
The team looking for the weakest point of gravity travels to a hilly region of Britain. They take gravity measurements at what seems like the perfect combination of latitude and altitude.
Credits: The Amazing World of Gravity: Part 1 (00:47)
Credits: The Amazing World of Gravity: Part 1
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