Chapter 8

Question 1

Atoms

Answer 1

a very small particle that makes up all things. Atoms have the same properties as the objects they make up

Question 2

Negatively electric charged

Answer 2

the charge on an atom or object with more electrons than protons

Question 3

Positively electric charged

Answer 3

the charge on an atom or object with fewer electrons than protons

Question 4

Protons

Answer 4

tiny, but heavy, particle found in the nucleus of an atom. Protons have a positive electrical charge

Question 5

Neutrons

Answer 5

tiny, but heavy, particles found in the nucleus of an atom. Neutrons have no electrical charge

Question 6

Electrons

Answer 6

very light, negatively charged particles inside an atom. Electrons move around the central nucleus of an atom

Question 7

Insulators

Answer 7

materials that do not allow electric charge to flow through them

Question 8

Conductors

Answer 8

materials that allow electric charge to flow through them

Question 9

Nucleus

Answer 9

roundish structure inside cells that acts as the control centre for the cell. Plural = nuclei

Question 10

Electrons

Answer 10

very light, negatively charged particles inside an atom. Electrons move around the central nucleus of an atom

Question 11

Positively charged

Answer 11

Any particle or substance that has more protons than electrons

Question 12

Negatively charged

Answer 12

Any particle or substance that has more electrons than protons

Question 13

Neutral

Answer 13

having the same number of protons and electrons

Question 14

Static electricity

Answer 14

A build of charge in one place.

Question 15

Lightning rods

Answer 15

conductive metal rod, often attached to the top of tall buildings. Lightning rods help to keep buildings sa

Question 16

Mass

Answer 16

a measure of the amount of material in an object of substance

Question 17

Weight

Answer 17

a measure of the size of the gravity force pulling an object towards the centre of a massive body, such as the Earth. The weight of an object depends on the object’s mass

Question 18

Terminal speed

Answer 18

the constant speed reached by a falling body. A body reaches terminal speed when the force of gravity pulling it down is balanced by the air resistance pushing against it

Question 19

Air resistance

Answer 19

the force of air pushing on an object as the object moves through the air

Question 20

Newton

Answer 20

the unit for measuring forces

Question 21

Gravity

Answer 21

the force of attraction that exists between any two bodies in the universe that have mass. The gravity at the Earth’s surface is the pull on objects near its surface towards the centre of the Earth

Question 22

Friction

Answer 22

a force that acts against the movement of an object. It occurs between any surfaces that are touching and trying to move past each other

Question 23

Lubricants

Answer 23

substance with large particles that can slide easily over each other. Lubricants are used between surfaces that rub against each other to reduce wear and increase motion between the surfaces

Question 24

Traction

Answer 24

a type of friction used to assist movement

Question 25

Buoyancy

Answer 25

a force which keeps objects floating

Question 26

Surface tension

Answer 26

the ‘firmness’ of the surface of a liquid created by the attraction between particles at the surface. The surface acts like an elastic skin