Ch.6.6

Question 1

Density is ______________________________________ and its unit is ____________ or _____________.

Answer 1

the mass per unit of a substance

g/cm3, kg/m3

Question 2

For the same volume, substances with ________________ ________________ have ________________ ________________.

Answer 2

higher density, greater mass

Question 3

Formula of density:

Answer 3

density (g/cm3)= mass (g)/ volume (cm3)

Question 4

The density of a substance ________________ ________________ with its ______________ or _____________.

Answer 4

doesn’t change, volume, mass

Question 5

Whether an object ________________ or ________________ in a liquid depends on its ________________.

Answer 5

floats, sinks, density

Question 6

An object ________________ in a liquid if its density is ________________ than that of a liquid. On the other hand, an object ________________ in a liquid if its density is ________________ than that of a liquid.

Answer 6

floats, lower, sinks, higher

Question 7

Why can the same lump of plasticine float after being kneaded into the shape of a boat?
The plasticine can ________________ in water after we have made it into a shape containing a ________________ ________________ __________ _____________, which is far ________________ ________________ than water.

Answer 7

float, large volume of air, less dense

Question 8

When the volume of an object ________________ and its mass remains ________________, its overall density ________________.

Answer 8

increases, unchanged, decreases

Question 9

Many ships are made from ________________, which is ________________ than water. However, the bodies of ships contain a ________________ ________________ ________ ____________ and this ________________ the ________________ ________________ of the ________________. Therefore, the ships can ________________ in water.

Answer 9

steel, denser, large volume of air, lowers, overall densities, ships, float

Question 10

The particles of a substance move ________________ ________________ when the substance is heated. This causes the substance to ________________, and since the ________________ of the substance ________________ while the ________________ remains ________________, the ________________ of the substance ________________. Similarly, when a substance is ________________, its particles move ________________ ________________. This results in a ________________ ________________ of the substance. Therefore, the density of the substance ________________.

Answer 10

further apart, expand, volume, increases, mass, unchanged, density, deceases, cooled, closer together, smaller volume, increases

Question 11

How do hot air balloons work?

• a hot air balloon works like a ________________ ________________
• when the air inside the hot air balloon is ________________, the air particles move ________________ and become ________________ ________________.
• The air expands so its ________________ ________________.
• the ________________ ________________ of the balloon becomes ________________ than the ________________ of the air around it and thus the balloon ________________

Answer 11

plastic bag
heated, faster, further apart, density decreases
overall density, lower, density, rises