Density

Measure weight, volume and density
Archimedes also discovered another curious fact about the property of objects called "density". When a less dense object is placed inside a more dense liquid, it floats. This reaction of the less dense object is called buoyancy.
By studying buoyancy in water via floating and measuring many objects, Archimedes discovered that the weight of a floating object isthe same as the weight of the water moved aside by it. So if we know how much a cubic inch of water weighs (its weight-density), we can weigh almost anything by making it float and we can measure its volume by submersion. The weight divided by the volume is the object's density.

In order to measure the weight of an object, you can:

1. Fill a container to the brim with water.
2.Place a plate or open plastic bag under the container.
3. Carefully put the object in the water. The water will overflow around the container into the plate or plastic bag. If the object does not float or would be damaged by water, seal it inside a plastic bag that you've blown some air into. Start over at step 1.
4. Carefully remove the container with the object without spilling from the bagor plate.
5. Pour the water from the bag or plate into a measuring cup.
6. Convert the measurement to weight by knowing there are 33.8 oz of water in a liter or 128 oz in a gallon of water (see the table below).

MEASURES AND WEIGHTS

|Unit |Weight (oz) |
|gallon|128 |
|half gallon |64 |
|quart |32 |
|pint|16 |
|cup |8 |
|tablespoon |1/2 |
|teaspoon|1/16 |

7. Remove the object from the water container.
Can you tell by looking at the picture which is more dense, pine or balsa? Both boats pictured weigh 2 ounces. Both boats displace the same volume and weight of water. But pine is about three times more dense than balsa.
[pic]

Inorder to measure the volume of a submerged object, you can:

1. Fill a container to the brim with water.
2. Place a plate or open plastic bag under the container.
3. Carefully put the object in the water, holding it under if necessary with narrow tongs or sticks. The water will overflow around the container into the plate or plastic bag.
4. Carefully remove the container with theobject without spilling from the bag or plate.
5. Pour the water from the bag or plate into a measuring cup.
6. Convert the measurement to volume in cubic inches by knowing there are 61 cubic inches (in3) of water in a liter or 230.9 in3 in a gallon of water (see the table below).

MEASURES AND VOLUME

|Unit |Volume (in3)|
|gallon |230.9 |
|half gallon |115.5 |
|quart |57.7...