Mass, Weight, Volume, Density, and Specific Gravity

Mass, Weight, Volume, Density, and Specific Gravity

Classifies solids according to their density

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Multiple Choice

The density of a substance cannot change.

• Disagree

• Agree

Multiple Choice

If you have twice as much material, you have twice as much weight but not twice as much density.

• Disagree

• Agree

Mass, Weight, Volume, Density, and Specific Gravity

• While we assign numbers to describe the typical density of a substance under standard conditions, changes in those conditions, temperature and pressure, result in changes in density.

• density is the result of the relationship between mass and volume. So even if you increase the amount of a material (assuming that it is homogeneous throughout), the density will remain the same.

Multiple Choice

If you divide an object in half, you have half as much volume and half as much weight but not half the density.

• Disagree

• Agree

Multiple Choice

Heavy things sink and light things float.

• Disagree

• Agree

Mass, Weight, Volume, Density, and Specific Gravity

• Density is the result of the relationship between mass and volume. So even if you decrease the volume of a material (assuming that it is homogenous throughout), the density will remain the same.

• Even though it is often the case, it is not always so. It depends upon the density of the object and the density of the liquid that it is floating in. If the density of the object is greater than the density of the liquid, the object will sink. If the density of the liquid is greater than the density of the object, then the object will float.

Multiple Choice

Objects either sink or float and it is helpful to make a list of sinkers and floaters.

• Disagree

• Agree

Multiple Choice

Air does not have mass or density. That is why it is so light.

• Disagree

• Agree

Mass, Weight, Volume, Density, and Specific Gravity

• Whether an object sinks or floats depends upon the relationship between the density of the object and the density of the liquid. An object can float in one liquid and sink in another. Labeling objects as sinkers or floaters underscores a simple linear model of sinking and floating that will contribute to difficulties of understanding later.

• The air and all gases do have mass and do have density. Understanding that gases have density and that different gases have different densities makes it possible to understand why we have layers in the atmosphere and why changes in temperature result in changes in the weather.

Multiple Choice

The spaces between the particles of an object are air.

• Disagree

• Agree

Multiple Choice

Not all wood floats.

• Disagree

• Agree

Mass, Weight, Volume, Density, and Specific Gravity

• While the spaces between the particles or molecules can be air in some instances of mixed density where air molecules fit in the gaps in the object material or in some kinds of materials (some cellulose or polymers), the spaces between the particles in a pure substance typically are not air. Often the molecules that make up the air will not fit there.

• Most wood floats, but it depends upon the density of the wood and the density of the liquid that it is floating in. Most wood will float in water because its density is less than that of water (1.0 g/ml), but some wood (lignum vitae, some samples of ebony) are denser than water and will sink in it.

Multiple Choice

Hollow objects always float.

• Disagree

• Agree

Multiple Choice

The density of 10 grams of water is:

• Twice the density of 20 grams of water

• Half the density of 20 grams of water

• The same density as 20 grams of water

Mass, Weight, Volume, Density, and Specific Gravity

• It actually depends upon the ratio of the density of surrounding material to the inside air and how the combined density of air plus material compares to the density of the liquid.

• It does not matter how much of a substance you have. Density is an intensive property of the material or substance and depends upon the relationship between the mass and volume. Unless the mass changes in relation to the volume, the density will not change.

Multiple Choice

What happens to the volume of an object when you cut it in half?

• It has half the volume

• It has twice the volume

• The volume stays the same

Multiple Choice

What happens to the mass of an object when you cut it in half?

• It has half the mass

• It has twice the mass

• The mass stays the same

Mass, Weight, Volume, Density, and Specific Gravity

• Volume refers to the amount of space that an object takes up. If you cut it in half, one half of it will take up half the amount of space of the original object.

• Mass is a measure of the matter in an object. In lay terms, it refers to the weight of the object on Earth. If you cut it in half, one half of it will have half the mass of the original object.

Multiple Choice

What happens to the density of an object when you cut it in half?

• It has half the density

• It has twice the density

• The density stays the same

Multiple Choice

When the mercury rises in a thermometer, compare to before it rose, is the mercury...

• more dense?

• less dense?

• the same density?

Mass, Weight, Volume, Density, and Specific Gravity

• It does not matter how much of a substance you have. Density is an intensive property of the material or substance and depends upon the relationship between the mass and volume. Unless the mass changes in relation to the volume, the density will not change.

• The same amount of mass is spread out over a greater area or volume. Therefore the density of the substance is less.