Experiments in weight and motion: falling bodies, water, and lifting
Dropping corks from a tower; weight in air, water and molten metal; the strength of a man
A page of experiments on weight and motion. Leonardo proposes dropping two corks of equal width but doubled length from a bell tower to measure how far the lighter one lags when the heavier strikes the ground, then notes how a weight seems lighter in water than in air and whether it sinks or floats in molten metal by its relative heaviness. He observes that movement through air is swifter than through water in proportion as air is thinner, provable with a sword, and that a weight resists more the more it touches the ground, shown by a rope stretched out versus gathered into a ball. Small marginal sketches of men lifting with a pulley and a balance accompany the closing note on the greatest force a man can exert by bracing his feet on a balance and his shoulders against something stable.
On this page
Dropping two corks from a bell tower
To test how much faster a one-ounce weight falls than a two-ounce one from the same height, drop two corks of equal width but doubled length together from a tower; when the heavier lands, mark which stone the lighter has reached and measure how far it lagged.
Weight in air, water, and molten metal
A weight in air shows the truth of its weight; in water it seems lighter in proportion as water is heavier than air. Cast onto molten metal it stays on top if lighter than the metal, and sinks if heavier.
Movement is swifter in air than in water
A movement made through air is swifter than one made in water, though both are driven by equal forces, in the same measure as air is thinner than water. You can prove this with a sword.
Resistance grows with contact on the ground
Where a weight has much contact with the ground, there is much resistance. A large rope stretched out and grasped by one end resists the mover, but gathered into a ball it moves with a small force.
The strength of a man lifting with a balance
A man pulling a weight in balance with himself cannot pull more than he weighs. His greatest force comes when he fixes his feet on one end of a balance and presses his shoulders against something stable, lifting from the far end a weight equal to his own plus all he can bear on his shoulders.