A nice interactive webpage by the BBC – The British Broadcasting Corporation: how you and the world have changed since you were born? You’re simply entering your birth date, gender, and height; selecting units (metric or imperial/US) and then watching how our planet (and you) has changed in your lifetime.
Continue reading Your Life On Earth (presented by BBC)
No, no no, and again: no! The Earth would NOT look like this without water. Please stop sharing this nonsense.
Continue reading No! The Earth Would NOT Look Like This Without Water
Here some numbers: the Earth has a diameter of about 12,735 kilometers (on average). The highest point on Earth is the top of Mt. Everest, at 8.85 km. The deepest point on Earth is the Mariana Trench, at about 11 km deep. Make the calculations and you can see, the Earth definitely would NOT look like below without water:
It’s one of the basic Newton laws: how fast something falls due to gravity is determined by a number known as the “acceleration of gravity”, which is 9.81 m/s2 at the surface of Earth. The acceleration of gravity, shortly “a” means that in one second, any object’s downward velocity will increase by 9.81 m/s because of gravity. The gravity accelerates everything at exactly the same rate.
Continue reading A Bowling Ball and Feather Falling in a Vacuum (video)
This also means a heavy object like a bowling ball and a lightweight object like a feather should fall down with the same speed, regardless of their shapes. But we see this phenomenon very rarely in our daily lives. The reason is the air resistance. That’s why people (including Aristotle) thought that the heavier objects fall faster for thousands of years.