Physical Science Unit 3

Front 1

A(n) ____ interaction is one in which objects exert forces on each other without being in contact

Back 1

Action-at-a-distance

Front 2

Examples of action-at-a-distance interaction?

Back 2

Magnetic, electric charge, and gravitational interactions

Front 3

Scientists use the idea of a ____ to account for action at a distance

Back 3

field of influence

Front 4

A ____ is an invisible entity that surrounds an object and the effect is to exert a force on any other relevant object within it.

Back 4

field

Front 5

The ______ of the field diminishes as the distance from the object it surrounds increases.

Back 5

strength

Front 6

our three examples the fields are called the ....

Back 6

magnetic field, electric field, and the gravitational field.

Front 7

When two magnets interact, or a single magnet interacts with objects made of certain ferromagnetic materials, we call this a ______

Back 7

magnetic interaction

Front 8

The only _____ materials are certain specific types of metal, such as iron and nickel.

Back 8

ferromagnetic

Front 9

The _____ of the magnetic forces resulting from such an interaction gets weaker the further apart the interacting objects are.

Back 9

strength

Front 10

Every magnet has two different ends (or faces), called _____

Back 10

North and South poles

Front 11

______ will always be attracted to either pole of a magnet.

Back 11

Non-magnetized ferromagnetic materials

Front 12

When two electrically charged objects interact, or a single charged object interacts with an uncharged object, we call this an ______

Back 12

electric charge interaction

Front 13

the forces exerted on electrically charged objects are called _____

Back 13

electrostatic forces

Front 14

All ______ materials will interact with a charged object.

Back 14

uncharged

Front 15

The strength of the electrostatic forces resulting from such an interaction gets _____ the further apart the interacting objects are.

Back 15

weaker

Front 16

When an object is electrically charged it has only one of two types of charge, called ....

Back 16

positive (+) or negative (–)

Front 17

When two objects are charged by rubbing together, they will always be______

Back 17

oppositely charged.

Front 18

When two charged objects are brought together, they will either always attract or always repel, regardless of ........

Back 18

how they are oriented

Front 19

Non-charged materials will always be attracted to any _____.

Back 19

charged object

Front 20

All objects contain a large number of very small + charges that ________, and a large number of very small – charges that _____.

Back 20

remain fixed in place ; are free to move and transfer from one object to another

Front 21

An _______ object is explained by it having equal numbers of + and ¬ charges

Back 21

electrically uncharged

Front 22

A + charged object has had some of its negative charges _____ and a – charged object has had extra negative charges _____

Back 22

removed ; added to it.

Front 23

When a pair of objects is charged by rubbing them together, negative charges are .....

Back 23

transferred from one to the other.

Front 24

When an uncharged object is brought close to a charged object, the _____ in the uncharged object are either attracted or repelled by the charged object (depending on whether it is + or – charged) and so rearrange themselves. This rearrangement results in _____ between the two objects

Back 24

– charges ; an overall attraction

Front 25

rearrangement of charges within the uncharged object is called _____ and the object is said to be ______

Back 25

polarization ;polarized

Front 26

The magnetic and electric charge interactions have different characteristics, so they must be different interactions. Thus we use different symbols when representing the objects involved; _____ for magnetic interactions and ____ for electric charge interactions.

Back 26

N and S ; + and –

Front 27

All objects with mass attract all other objects with mass via the ________

Back 27

gravitational interaction

Front 28

The strength of the forces interacting objects exert on each other depends on both their ____ and the ____ between them.

Back 28

masses and the distance

Front 29

For everyday pairs of objects (such as two people) the forces are.....

Back 29

so weak that they are not noticeable.

Front 30

if one of the objects involved has a very large mass (such as a planet like the Earth) then the gravitational force is ....

Back 30

strong enough to have a significant effect.

Front 31

Although the strength of the Earth’s gravitational force does diminish very gradually as you get further from the Earth, because the Earth is so large its strength can be taken to be _____ for objects moving close to its surface.)

Back 31

constant

Front 32

When the effects of the air can be neglected all objects fall with the same rate of increasing speed. This happens because the strength of the gravitational force acting on an object depends on its mass in such a way that the____ is the same for all objects.

Back 32

ratio of force strength to mass

Front 33

When an object moves through the air, the air exerts a force on it in the opposite direction to its motion. The strength of this force, called the_____, increases in strength as the object’s speed increases.

Back 33

drag force or air resistance

Front 34

Eventually an object may reach a speed at which the drag force exactly balances the force pushing or pulling it forward and so from then on it moves at a constant speed - called the object’s C_____

Back 34

terminal velocity.

Front 35

Several objects or entities may be considered as a _____

Back 35

single system.

Front 36

If there are interactions between objects inside and objects outside the system, then there may be ....

Back 36

an energy input to, and/or an energy output from, the system

Front 37

. If the only interactions that occur are between objects within the system, then there ....

Back 37

is no such energy input or output.

Front 38

We infer the existence of a form of ____ that resides within any system involving an action-at-a-distance interaction.

Back 38

potential energy

Front 39

It is useful to think of this potential energy as being ‘stored’ in the _____, and so it is useful to consider the field as part of the system also

Back 39

field of influence

Front 40

Each different action-at-a-distance interaction has a form of potential energy associated with its particular field:

Back 40

magnetic potential energy, electrostatic potential energy, and gravitational potential energy.

Front 41

When two objects are attracting each other through an action-at-a-distance interaction, as they get further apart the potential energy associated with the relevant field _____

Back 41

increases.

Front 42

When two objects are repelling each other through such an interaction, as they get further apart the potential energy associated with the relevant field _____.

Back 42

decreases

Front 43

If there is no energy input to, or output from, a system, then the total energy in the system must ______ . When the kinetic energy in such a system increases, the potential energy in the system must _____, and vice versa.

Back 43

stay constant ; decrease by an equal amount

Front 44

When two objects attract each other through an action-at-a-distance interaction, it is possible to start one of them moving away from the other fast enough that not all the____ in the system can ever be transformed into_____. Thus the object will never stop and will keep moving away forever. The minimum initial speed necessary for this to occur is called the _____

Back 44

kinetic energy ; potential energy ; escape velocity.

Front 45

An ______ is what you actually see or hear or otherwise collect with your senses or measure with an instrument

Back 45

observations

Front 46

When you make_____, you use your ideas and the evidence provided by observations to try to make sense of what is happening.

Back 46

inferences

Front 47

In science, ______ are generalizations that describe a phenomenon (but may include theoretical constructs such as mass, charge, and energy). They do not generally explain a phenomenon and are usually derived through experiments and observations.

Back 47

laws

Front 48

In science, the word ____ refers to a set of ideas and representations that may be used to explain a phenomenon.

Back 48

model

Front 49

The development of scientific knowledge requires several processes, including the use of _____

Back 49

creativity, logical thinking, and evidence.

Front 50

______ is used to come up with new models and to pose new questions.

Back 50

Creativity

Front 51

______ is used to connect claims to evidence

Back 51

Logical thinking

Front 52

______ is used to support or challenge claims.

Back 52

Evidence

Front 53

A diagram can be used to represent the model for charges in materials. Several + and – signs are used to represent the tiny charges in an object. In keeping with the assumptions of the model, + charges should not move in a series of such diagrams of the same object, whereas – charges may change location within an object, or transfer between objects.

Back 53

Charge Model Diagram