Year 9 Test 1 - Thermal Physics

Question 1

fundamental statements about heat

Answer 1

heat is a store of energy;
is measured in Joules (J);
we say that an object has a thermal store of energy;
an object stores more thermal energy the hotter it is (cold objects have a bit of heat as well);
an object can lose energy - it’s thermal store empties as it cools down

Question 2

heat transfer

Answer 2

heat can move from one object to another;
heat only EVER moves from hot objects to colder ones;
the bigger the temperature difference between two objects, the faster it moves;
measure in Joules/second (J/s)

Question 3

matter

Answer 3

all matter consists of tiny particles (atoms/groups of atoms)
there are attractive forces between particles (like to stick to each other)
particles may move around/rearrange but they are never destroyed (nor a new ones created)

Question 4

rigidity

Answer 4

rigidity > how easy it is to change it’s shape

Question 5

compressibility

Answer 5

compressibility > how easy it is to change its volume

Question 6

density

Answer 6

how much mass/particles in a fixed volume

Question 7

states of matter - solids

Answer 7

regular arrangement; very close together

Question 8

states of matter - liquids

Answer 8

random arrangement; close together

Question 9

states of matter - gases

Answer 9

random arrangement; far apart

Question 10

life cycle of a gas particle

Answer 10

moving quickly > collide with another gas particle/solid surface > moving quickly

Question 11

particles in a solid

Answer 11

rigid and not easily deformed - strong chemical bonds between neighbouring particles keep them keep them held in place
regularly arranged; vibrate a little around their fixed positions

Question 12

particles in a liquid

Answer 12

close to to other particles
move around the liquid; not fixed in place
weakly bonded to neighbouring particles (change when particles move)

Question 13

formula for density

Answer 13

density of a substance = mass/volum

Question 14

most common units for density

Answer 14

g/cm3

kg/m3

Question 15

important density statement

Answer 15

density of an object doesn’t change, even if the object is bigger/smaller