Density is mass per unit volume:
Density is mass per unit volume
Gold is very dense - it feels very heavy for its size.:
Gold is very dense - it feels very heavy for its size. D = 19.3g/cm3
Plastic is not very dense - it feels light for its size.:
Plastic is not very dense - it feels light for its size. P = 1g/cm3
Each substance has its own density. A larger amount will still have the same density because it will be an equivalent fraction. :
Each substance has its own density. A larger amount will still have the same density because it will be an equivalent fraction.
Solving for density: mass or density volume volume/ mass :
Solving for density: mass or density volume volume/ mass Examples:
water: 100ml 100g = 1g/ml
glass: 1ml 4g = 4g/ml
I can make something have less density by increasing the volume until it is more than the mass. :
I can make something have less density by increasing the volume until it is more than the mass.
RULE OF JAMIE (a former student)::
RULE OF JAMIE (a former student): Anything with a density less than one will float in water. If there are numbers to the left of the decimal it will sink!
So why do ships float ?:
So why do ships float ? The density of steel is 7.8 g/cm3
The density of waters 1 g/cm3 Think of a steel ship as a can that is empty and watertight. The majority of its space is taken up by nothing more than air which has a specific gravity of about 0.00129. So if a make a ship that is like a can, empty inside and watertight it floats. Its volume sufficient that it causes its specific gravity to remain below 1.0 even after adding the weight of its contents.
The steel ship will remain afloat as long as its density remains below that of water. The problem is that if water is allowed to enter the ship it would sink. Ships made of steel have to be sealed so water can not get in and increase its density.
Steel can float only because of the way it is shaped, the space it takes up, and the seal that keeps its watertight. The ability of steel to float is the ability of people to shape metal and solve problems by examining outcomes.