Y7 Science Year End (Chem and Physics) Flashcards
(361 cards)
1
Q
What are the three states of matter?
A
Solid, liquid and gas
2
Q
What are all things around us made of?
A
Particles
3
Q
Describe the arrangement of particles in solids.
A
Regular arrangement; touching
4
Q
Describe the arrangement of particles in liquids.
A
Random arrangement; touching
5
Q
Describe the arrangement of particles in gases.
A
Random arrangement; not touching
6
Q
How do the particles in gases move?
A
Randomly in every direction until bumping into each other or their container
7
Q
How do the particles in liquids move?
A
Moving over each other randomly
8
Q
How do the particles in solids move?
A
Vibrate around a fixed point
9
Q
Give two properties of gases.
A
Can flow; can be compressed
10
Q
Give two properties of liquids.
A
Can flow; cannot be compressed
11
Q
Give two properties of solids.
A
Cannot flow; cannot be compressed
12
Q
Why can solids not flow?
A
There are strong forces of attraction between the particles
13
Q
Why can liquids and gases flow?
A
There are weak forces of attraction between the particles
14
Q
Why can gases be compressed?
A
There is space between the particles
15
Q
Why can solids and liquids not be compressed?
A
The particles are already touching
16
Q
Sketch the particles in a solid
A
Solid
17
Q
Sketch the particles in a liquid
A
Liquid
18
Q
Sketch the particles in a gas
A
Gas
19
Q
What is the name for the process when a substance changes from a gas to a liquid?
A
Condensation
20
Q
What is the name for the process when a substance changes from a liquid to a gas, at the boiling point?
A
Boiling
21
Q
What is the name for the process when a substance changes from a liquid to a gas, below the boiling point?
A
Evaporation
22
Q
What is the name for the process when a substance changes from a liquid to a solid?
A
Freezing
23
Q
What is the name for the process when a substance changes from a solid to a liquid?
A
Melting
24
Q
What is the boiling point of a substance?
A
The temperature at which a substance changes from liquid to a gas
25
What is the melting point of a substance?
The temperature at which a substance changes from solid to a liquid
26
What temperature is the boiling point of water?
100°C
27
What temperature is the melting point of water?
0°C
28
What happens to the temperature of a substance while it changes state?
It stays the same
29
What piece of apparatus is used to measure change in temperature?
Thermometer
30
What is a hazard ?
A source of harm
31
What is a risk?
The likelihood that a hazard will cause harm
32
What is a safety precaution?
Something you do to minimise risk
33
What is the hazard associated with using a Bunsen burner?
Burning
34
What safety precautions should be taken when using a Bunsen burner?
Light it using the safety flame; Turn it to the safety flame when not in use; Wear goggles
35
In the graph below, what does the temperature at A represent?
Boiling point
36
In the graph below, what does the temperature at B represent?
Melting point
37
What is the process called when a substance changes directly from a solid to a gas?
Sublimation
38
How does the speed of diffusion compare in gases compared to liquids?
Gases diffuse faster due to greater and faster particle movement
39
How does the speed of diffusion compare for a light molecule, like Helium, compared to a heavy molecule like Bromine?
The light molecule (Helium) will move faster than the heavy molecule (Bromine) and therefore it will diffuse faster
40
What is a pure substance?
A single element or compound that isn't mixed with another substance
41
How can the purity of a substance be tested?
The purity of a substance can be tested by comparing its m.p. or b.p. to the m.p. or b.p. of the pure substance. A pure substance has specific m.p.s and b.p.s.
42
How is the melting point of a pure substance different from that of an impure substance?
A pure substance has one specific melting point. An impure substance has a melting range.
43
How is the melting and boiling point of an impure substance affected?
m.p. decreases, b.p. increases
44
What happens to the temperature of a substance as it changes state?
The temperature stays the same
45
What happens to the energy of the particles as a substance heats up?
Increases
46
What happens to the energy of the particles as a substance cools down?
Decreases
47
What is diffusion?
The movement of particles from an area of high concentration to an area of low concentration
48
What is kinetic theory?
The idea that all particles are moving
49
What causes gas pressure?
Gas particles colliding with the surface of a container
50
What three factors affect gas pressure?
Temperature, size of the container, number of gas particles
51
What is the relationship between temperature and gas pressure?
As temperature increases, the gas pressure increases
52
What is the relationship between the size of a container and gas pressure?
As the size of the container decreases, the gas pressure increases
53
What is the relationship between gas pressure and the number of gas particles?
As the number of gas particles increases, the gas pressure increases
54
What happens to particles when you heat them up?
They move faster
55
What are all substances made of?
Atoms
56
What is an atom?
The smallest unit of matter than can exist on its own
57
How many different types of atom are there?
92 (naturally occurring)
58
Where are the different types of atoms listed?
The Periodic Table of elements
59
What are the vertical columns on the Periodic Table called?
Groups
60
What are the horizontal rows on the Periodic Table called?
Periods
61
What is an element?
A substance made up of only one type of atom
62
What are subatomic particles?
The particles that make up atoms
63
Which three subatomic particles are atoms made of?
Protons, neutrons and electrons
64
What is found in the centre of an atom?
Nucleus
65
Which subatomic particles are found in the nucleus of an atom?
Protons and neutrons
66
Where are the electrons found in an atom?
In shells around the nucleus
67
What is an atom’s atomic number?
Number of protons in an atom
68
What is an atom’s atomic mass?
Number of protons and number of neutrons added together
69
How many electrons do atoms have?
The same as the number of protons
70
What is the maximum number of electrons that can be held in each electron shell?
First shell 2, second shell 8, third shell 8
71
What does the group number of the Periodic Table tell you about the electron arrangement?
Number of electrons in the outer shell of an atom
72
What does the period number tell you about the electron arrangement?
Number of electron shells in an atom
73
What is the name for the one or two letters that are used to represent a type of atom?
Chemical symbol
74
What form do chemical symbols take?
One capital letter or one capital letter and one lower case letter
75
What is a molecule?
A small number of atoms joined together
76
What do we call the chemical symbols and numbers that tell us how many of each type of atom are in a substance?
Chemical formulae
77
What is the chemical formula for oxygen?
O₂
78
What is the chemical formula for water?
H₂O
79
What is the chemical formula for carbon dioxide?
CO₂
80
What is the chemical formula for methane?
CH₄
81
What is the chemical formula for common table salt (sodium chloride)?
NaCl
82
What are the names of the elements, H₂, He, and Li?
Hydrogen, Helium, Lithium
83
What are the names of the elements, Be, B, and C?
Beryllium, Boron, Carbon
84
What are the names of the elements, N₂, O₂, and F₂?
Nitrogen, Oxygen, Fluorine
85
What are the names of the elements, Ne, Na, and Mg?
Neon, Sodium, Magnesium
86
What are the names of the elements, Al, Si, and P?
Aluminum, Silicon, Phosphorus
87
What are the names of the elements, S, Cl₂, and Ar?
Sulfur, Chlorine, Argon
88
What are the names of the elements, K and Ca?
Potassium, Calcium
89
What is a compound?
A substance made from two or more different types of element chemically bonded together
90
What is the difference between an element and a compound?
A element contains only 1 kind of atom, a compound contains 2 or more elements which are chemically combined
91
What is meant by the ‘chemical properties’ of a substance?
The way in which the chemical reacts with other substances
92
What is meant by the ‘physical properties’ of a substance?
The characteristics of a substance that are not related to the way it reacts
93
Give three examples of physical properties.
Melting point, boiling point, conductivity
94
What is a hazard?
A source of harm
95
What is a risk?
The likelihood that a hazard will cause harm
96
What is a safety precaution?
Something you do to minimise risk
97
Define ‘pure’.
A substance made of only one type of atom, molecule or compound
98
What is a mixture?
A substance made of more than one type of atom, molecule or compound, not chemically joined together
99
Define ‘soluble’.
Able to dissolve in a given solvent
100
When a solid dissolves in a liquid, what is formed?
A solution
101
What do we call the soluble substance that dissolves in a liquid?
Solute
102
What do we call the liquid that a substance dissolves into to form a solution?
Solvent
103
Define ‘saturated solution’.
One in which no more solute can dissolve
104
What word do we use to describe how easily a solute dissolves?
Solubility
105
Describe the relationship between solubility and temperature.
As temperature increases, solubility increases
106
State four types of chemical reaction.
In a chemical reaction, reactants turn into products – they are different, not the same
107
Where are the reactants in a chemical equation?
To the left of the →
108
Where are the products in a chemical equation?
To the right of the →
109
What happens in a chemical reaction?
Chemical bonds in the reactants are broken, the atoms are rearranged and new bonds are made in the products
110
What is a catalyst?
Substance that increases the rate of a reaction without being used up
111
What is an enzyme?
Biological catalyst made of protein
112
What are state symbols?
Letters in symbol equations that denote the states of matter of chemicals.
113
What are the four state symbols?
Solids (s), liquids (l), gases (g) and aqueous solutions (aq)
114
What is an aqueous solution?
A solid that has been dissolved in water, e.g. salt water.
115
Give five ways in which we can tell that a chemical reaction has taken place.
Temperature change, light or flame produced, change of colour, effervescence, precipitation of a solid
116
What is effervescence?
Bubbling caused by a gas being produced
117
What is precipitation?
When an insoluble solid is formed in a solution
118
What is the difference between a chemical reaction and a physical change?
Chemical reactions produce new substances and are not easily reversed; physical changes do not produce new substances and are easy to reverse
119
State four types of chemical reaction.
Combustion, thermal decomposition, oxidation and displacement
120
What is the name for reactions in which fuels are burned in oxygen?
Combustion
121
What are the three sides of the fire triangle?
Heat, fuel and oxygen
122
What happens if one side of the fire triangle is removed?
The fire goes out
123
What are the usual products of combustion reactions?
Carbon dioxide and water
124
What is a thermal decomposition reaction?
A reaction where heating is used to break one reactant into two or more products
125
What is the chemical test for carbon dioxide?
Bubble the gas through limewater, which turns from clear to cloudy white
126
What is an oxidation reaction?
When an element is chemically combined with oxygen
127
Write the word equation for the combustion of carbon
Carbon + Oxygen → Carbon Dioxide
128
Write the word equation for the combustion of sulfur
Sulfur + Oxygen → Sulfur Dioxide
129
Write the word equation for the combustion of methane (CH₄)
Methane + Oxygen → Carbon Dioxide + Water (Note: each element in the original compound forms its oxide)
130
What is the product of the oxidation of a metal?
Metal oxide
131
What is a displacement reaction?
When a more reactive element displaces a less reactive element from its compound
132
What is the law of conservation of mass?
The mass of all the reactants is equal to the mass of all the products
133
What is a balanced symbol equation?
An equation where there are the same number and type of atoms on each side
134
Why can it appear that a reaction has gained mass?
When a gas is a reactant and its atoms become part of the products
135
Why can it appear that a reaction has lost mass?
When atoms of a gas are produced during the reaction, which then escape
136
What piece of equipment is used to measure temperature change?
Thermometer
137
In chemistry, what is meant by the phrase ‘the surroundings’?
Everything that is not the reaction itself, including the thermometer
138
Define ‘endothermic’.
A process that takes in energy from the surroundings
139
Define ‘exothermic’.
A process that releases energy into the surroundings
140
Give an example of an endothermic reaction.
Thermal decomposition
141
Give an example of an everyday use of endothermic reactions.
Instant cold packs
142
Give two examples of an exothermic reaction.
Neutralisation, combustion
143
Give an example of an everyday use of exothermic reactions.
Reusable handwarmers
144
Is melting endothermic or exothermic?
Endothermic
145
Is freezing endothermic or exothermic?
Exothermic
146
Is evaporating endothermic or exothermic?
Endothermic
147
Is condensing endothermic or exothermic?
Exothermic
148
What happens to the temperature of the surroundings during an exothermic reaction?
It increases
149
How does an endothermic reaction affect the temperature of the surroundings?
It decreases the surroundings temperature
150
What are acids?
Solutions with pH less than 7
151
What are bases?
Substances that can react to cancel out acids
152
What are alkalis?
Soluble bases with pH greater than 7
153
Name three examples of household acids.
Vinegar, lemon juice, fizzy drinks
154
Name three examples of household alkalis.
Bleach, toothpaste, soap
155
What hazards are there in working with lab acids and alkalis?
They are corrosive
156
What pH do neutral solutions have?
pH 7
157
What is an indicator?
A chemical that changes colour depending on the pH of the solution
158
What colour is Universal Indicator in acids?
Red, orange or yellow
159
What colour is Universal Indicator in alkalis?
Blue or purple
160
What colour is Universal Indicator in neutral solutions?
Green
161
Name three common lab acids and their formulae.
Hydrochloric acid (HCl), nitric acid (HNO₃) and sulfuric acid (H₂SO₄)
162
Name a common lab alkali and its formula.
Sodium hydroxide (NaOH)
163
What type of reaction occurs between an acid and a base?
A neutralisation reaction
164
What is the general equation for a neutralization reaction?
Acid + Base → Salt + Water
165
What is the equation for the reaction of hydorchloric acid and sodium hydroxide?
HCl + NaOH → NaCl + H₂O
166
What are the products of a neutralisation reaction?
A salt and water
167
What is produced when an acid reacts with a metal?
A salt and hydrogen
168
What is the test for hydrogen gas?
A lit splint produces a squeaky pop
169
What salts are produced by hydrochloric acid?
Metal chlorides
170
What salts are produced by nitric acid?
Metal nitrates
171
What salts are produced by sulfuric acid?
Metal sulfates
172
what happens when a base if added to an acidic lake?
the pH of the lake water increases, making it less acidic and allowing more organisms to live there safely
173
Why are acids aor bases sometimes added to soil?
Adding bases or acids to soil can change its pH, making it suitable for different crops
174
What is the hazard associated with using acids?
They are corrosive
175
What does corrosive mean?
Can damage your skin
176
What safety precautions should be taken when using acids?
Wear goggles; Use dilute acid; Clean up spills immediately
177
What is a force?
A push or a pull
178
What unit do we use to measure the size of a force?
Newton, N
179
What instrument can be used to measure the size of a force?
A newtonmeter
180
How can we show forces on a diagram?
As arrows
181
In a force diagram, what does the direction of an arrow show?
The direction of the force
182
In a force diagram, what does the length of an arrow show?
The longer the arrow, the bigger the force
183
What do we call it when two objects act on each other with a force?
An interaction
184
How many forces are produced during one interaction between objects?
Two
185
What are contact forces?
Forces that only happen when objects touch
186
What are non-contact forces?
Forces that can happen even when the objects are not touching
187
What is the name of the force when a person pushes or pulls an object?
Applied force
188
What is the name of the force produced when solid surfaces rub against each other?
Friction
189
What is the name of the force produced by engines?
Thrust
190
What is the name of the force produced when an object moves through the air?
Air resistance
191
What is the name of the force produced when an object moves through water?
Water resistance
192
What is the name of the force that stops objects sinking in water?
Upthrust
193
What is the name of the force that pulls objects towards Earth?
Weight
194
What is the name of the force that stops objects falling through solid surfaces?
Normal contact force
195
What is the name of the force that stops airplanes falling down towards Earth?
Lift
196
Name two non-contact forces.
Weight, magnetism
197
Name the eight contact forces.
Friction, thrust, air resistance, water resistance, lift, normal contact, applied force, upthrust
198
What is weight?
A force acting on a mass due to it being in a gravitational field
199
In which direction does an object’s weight on Earth always point?
Towards the centre of the Earth
200
What unit do we use to measure weight?
Newtons, N
201
What is mass?
A measure of how much matter is in an object
202
What unit do we use to measure mass?
Kilograms, kg
203
If an object moves from one planet to another, does its mass change?
No
204
If an object moves from one planet to another, does its weight change?
Yes
205
In words, what equation links weight, mass and gravitational field strength?
Weight = mass × gravitational field strength
206
In symbols, what equation links weight, mass and gravitational field strength?
W = m × g
207
What is the relationship between mass and weight?
The larger the mass, the larger the weight
208
What is the relationship between gravitational field strength and weight?
The larger the gravitational field strength, the larger the weight
209
What unit do we use to measure gravitational field strength?
Newtons per kilogram, N/kg
210
What is the gravitational field strength of Earth?
10 N/kg
211
What is meant by accuracy?
Whether the results of an experiment are roughly what they should be
212
If a mass of 5 kg is placed in a gravitational field of 10 N/kg, what is its weight?
The weight is 50 N. (You find this by multiplying 5 kg by 10 N/kg: 5 kg × 10 N/kg = 50 N.)
213
If a mass of 500 g is placed in a gravitational field of 10 N/kg, what is its weight?
The weight is 5 N. (First, change 500 g to kg, which is 0.5 kg. Then multiply: 0.5 kg × 10 N/kg = 5 N.)
214
What do we call two forces that are equal in size and opposite in direction, whilst acting on a single object?
Balanced forces
215
What do we call two forces that are not equal in size but are opposite in direction acting on a single object?
Unbalanced forces
216
What is the relationship between the size of a force and the length of the arrow that represents it?
The greater the force, the longer the force arrow
217
What do we draw to show the forces acting on an object?
A force diagram
218
What happens to an object when the forces acting on it are balanced?
There is no change to the object’s speed or direction or shape
219
What is the name of the overall force when you add all the forces acting on an object?
The resultant force
220
What is the resultant force when forces are balanced?
Zero
221
Define "equilibrium of forces"
When the net force acting on an object is zero, all the forces acting on the object are balanced.
222
Give an example of a situation where friction is beneficial.
Friction is helpful when you walk. It stops you from slipping and helps you stay on the ground.
223
How would you reduce air resistance on a car?
You can reduce air resistance on a car by making it more streamlined. This means making the shape of the car smooth and pointed, so air can flow easily around it.
224
Describe a scenario where friction is a disadvantage.
A conveyor belt in a factory. If the friction is too high, it can lead to heating and then to increased wear on the components.
225
How does the shape of an object affect air resistance?
Streamlined shapes like a plane, have low air resistance, blunt shapes like a flat piece of cardboard, have high air resistance
226
What happens to a ball thrown upwards when it reaches its highest point in terms of forces?
When the ball reaches its highest point, it stops going up. The force of gravity pulls it down. At that moment, the ball's speed is zero before it starts to fall back down.
227
Describe a scenario where air resistance is significant.
Air resistance is important when a parachute opens. The parachute catches the air and slows down the person falling, making it safer.
228
What happens when the forces on a stationary object become unbalanced?
It begins to move
229
What three things can happen when the resultant force acting on an object is not zero?
It speeds up, slows down or changes direction
230
What happens to a moving object when the resultant force is zero?
It continues to move at a constant speed
231
What happens to a stationary object when the resultant force is zero?
It remains stationary
232
What is the relationship between the size of a resultant force and the size of the change in motion?
The greater the resultant force, the greater the change in motion
233
Give three ways in which the shape of an object can be changed.
Stretching, compressing or bending
234
Describe what it means to stretch an object.
To increase its length.
235
Describe what it means to compress an object.
To decrease its length.
236
Define elastic deformation.
When an object returns to its original shape and size after the applied forces are removed.
237
Define inelastic deformation.
When an object does not return to its original shape and size after the applied forces are removed.
238
State the specific mathematical relationship between the force applied to a spring and the extension of the spring.
Directly proportional
239
Describe the relationship between the force on an elastic object and its extension.
As the force on an elastic object increases, the extension increases.
240
Define the limit of proportionality of an elastic object.
The maximum extension after which the elastic object no longer returns to its original shape and size after the applied forces are removed.
241
In words, state the equation that links force, extension and spring constant.
force = spring constant × extension
242
In symbols, state the equation that links force, extension and spring constant.
F = k × e
243
State the standard units for force.
Newtons (N)
244
State the standard units for spring constant.
Newtons per metre (N/m)
245
State the standard units for extension.
Metres (m)
246
State how the extension of an elastic object is calculated.
new length - original length
247
Define spring constant.
The force required to extend (or compress) an elastic object by 1 m.
248
State the standard units for extension.
Metres (m)
249
When investigating how the force on a spring affects its extension, name the independent variable.
Force applied to the spring
250
When investigating how the force on a spring affects its extension, name the dependent variable.
Extension of the spring
251
When investigating how the force on a spring affects its extension, name two variables that need to be controlled.
Temperature of the spring and spring constant of the spring
252
Describe how the extension of a spring is measured.
By measuring the stretched length and subtracting the initial length.
253
State what the extension of a spring should be when zero force is applied.
0 m
254
Describe how a mass is converted into a weight.
By using the equation for weight and multiplying the mass by the gravitational field strength the mass is in.
255
A student wants to measure how the force applied to a piece of elastic affects the extension. Outline a method to do this. Ensure the method would lead to valid results.
Suspend the piece of elastic from a horizontal support. Measure the initial length of the piece of elastic. Exert a force on the elastic by attaching one slot mass to the elastic. Measure the new length of the piece of elastic. Calculate the extension by subtracting the initial length from the new length. Add more masses and repeat.
256
When the force on a spring is doubled, state the expected effect on the extension of the spring.
It should double.
257
What is an oscillation?
A repeated backwards and forwards motion (or a repeated increase and decrease)
258
What is a medium?
The material through which a wave passes (can be a vacuum)
259
Give four examples of a medium.
Air, glass, water, a vacuum
260
What is a wave?
An oscillation that carries energy
261
What does a wave transfer from one place to another?
Energy
262
What does a wave not transfer from one place to another?
Particles/matter/‘stuff’
263
What are the names of the two types of wave?
Longitudinal and transverse
264
How are the direction of the oscillation and direction of the wave related in a transverse wave?
The oscillations are at right angles to the direction of the wave
265
How are the direction of the oscillation and direction of the wave related in a longitudinal wave?
The oscillations are parallel to the direction of the wave
266
What type of wave is a water wave?
Transverse
267
What type of wave is light?
Transverse
268
What type of wave is sound?
Longitudinal
269
What are the 3 key properties we use to describe a wave?
Amplitude, wavelength, frequency
270
How is wavelength defined in a wave?
The length in meters of a single oscillation. This is the distance between 2 consecutive peaks or 2 consecutive troughs.
271
How is Amplitude defined in a wave?
The height of a wave from its centre line to a peak, or to a trough.
272
What is it called when a wave bounces off a surface (or any change in medium)?
Reflection
273
What is oscillating when sound travels?
The particles in the medium through which it travels
274
What types of medium can sound travel through?
Solids, liquids and gases
275
Why can sound not travel in a vacuum?
There are no particles to oscillate in a vacuum
276
Why does sound travel faster in solids than in gases?
The particles are closer together, so vibrations travel faster as the particles touch each other.
277
What is the frequency of a wave?
The number of oscillations that happen every second
278
What unit do we use to measure frequency?
Hertz, Hz
279
What is the hearing range of humans?
20–20 000 Hz
280
What is the relationship between the amplitude of a sound wave and its volume?
The larger the amplitude, the louder the sound
281
What is the relationship between the frequency of a wave and the pitch of the sound?
The higher the frequency, the higher the pitch
282
What is the unit for the loudness of a sound?
decibel (dB)
283
When sound travels from one medium to another, what two things can happen?
It can reflect back into the original medium or it can be absorbed in the new medium (or a combination of both)
284
What is an echo?
A reflected sound wave
285
How are all types of sounds produced?
By a physical object vibrating or oscillating
286
Which part of our ear vibrates to detect sound?
Ear drum
287
How do our ears detect sound?
The particles in the air oscillate due to the sound; they hit our ear drum, making it vibrate
288
What are the functions of the cochlea and semi-circular canals in the inner ear?
The cochlea convert sound vibrations into electrical signals. The semi-circular canals maintain balance and spatial orientation.
289
What is the common name given to the 3 bones that make up the ossicles?
Hammer, Anvil and Stirrup
290
What is constructive interference?
When waves add together to make a larger amplitude
291
What is destructive interference?
When waves cancel each other out
292
Speakers and microphones contain a diaphragm. What is a diaphragm?
An elastic membrane that can vibrate
293
How does a speaker work?
The speaker makes the diaphragm vibrate; this collides with particles in the air, making them oscillate, forming a sound
294
How does a microphone work?
The particles in the air oscillate due to the sound colliding with a diaphragm in the microphone, causing it to vibrate
295
What is ultrasound?
Sound with a frequency above that of human hearing (above 20 kHz)
296
How can we use ultrasound to find the distance to an object?
Emit ultrasound and time how long it takes to hit the object, reflect back and be detected; use the known value for the speed of the wave and the equation for speed to find the distance
297
What are some practical applications of ultrasound in medicine and industry?
To monitor fetal development during pregnancy. Ultrasonic cleaning uses high-frequency sound waves in a cleaning solution to remove dirt, grease, and contaminants from delicate items like jewelry and electronic components.
298
Which animals use ultrasound to navigate?
Bats use echolocation.
299
What is a luminous source?
an object that emits its own light, like the sun.
300
What is oscillating in a light wave?
The electromagnetic field
301
What type of wave is light?
Transverse
302
What is the name of the energy transfer when light transfers energy?
Energy transfer by waves
303
What is a vacuum?
A region in which there are no particles at all
304
Why can light travel through a vacuum?
It does not need particles to travel
305
What happens to the speed of light as it moves from a vacuum to gas to liquid to solid?
It gets slower
306
What happens if we increase the amplitude of a light wave?
It gets brighter
307
What three things can happen to light when it hits a new material?
It can reflect, it can be transmitted through the material, it can be absorbed
308
What path does light take to travel from A to B?
A straight line
309
How do we represent light in a ray diagram?
As a straight line with an arrow
310
What is a light-year, and why is it used?
A unit of distance equal to the distance that light travels in a vacuum in one year = 9.5 trillion km.
311
What are 3 things that can happen to light when it strikes and object?
Transmission, absorption, reflection
312
What happens to light when it hits a transparent material?
Most of the light is transmitted
313
What happens to light when it hits an opaque material?
The light is absorbed and/or reflected
314
What happens to light when it hits a translucent material?
Some of the light is transmitted and the rest is absorbed and/or reflected.
315
What causes light to change direction when it changes medium?
Light travels at different speeds in different mediums
316
What causes refraction?
Changes to a wave’s velocity in different media
317
Define refraction.
When a wave changes direction when it enters a new medium.
318
Give three scenarios in which refraction does not happen.
When the wave is reflected. When the wave hits the new medium along the normal line. When there is no change in density.
319
When does reflection occur?
When light (or any wave) hits a new medium and bounces away from it
320
What is the law of reflection?
When a wave strikes a reflective surface, the angle of incidence is equal to the angle of reflection
321
What is the difference between regular and diffuse reflection?
Regular reflection happens with smooth surfaces (uniform reflection = parallel rays of incident light reflect to form parallel rays of reflected light). Diffuse reflection happens with rough surfaces (parallel rays of incident light reflect in all directions)
322
In the human eye, which part focuses the light?
The lens
323
In the human eye, what is the name for the opening through which light passes through?
The pupil
324
In the human eye, what is the name for the part that detects light?
The retina
325
In the human eye, what is the name for the part that sends messages to the brain?
The optic nerve
326
What happens to light in a lens?
Light is refracted to change its direction and focus it
327
What colours of light pass through a red filter?
Red only
328
What colours of light do green objects absorb?
All colours except green
329
If white light is shone on a green fliter and then a red filter, what colour light will be seen.
None,no light passes both filters. The green filter only lets through green light and the red filter would only allows red light through
330
what are the primary colours of light?
red, green and blue
331
what are the secondary colours of light?
cyan, magenta and yellow
332
How are the secondary colours of light formed?
by mixing the primary colors of light (red, green, and blue) in equal amounts
333
What colour of light is formed if all colours are mixed together?
white
334
What happens when the wavelength of light changes?
The colour changes
335
What are the seven colours of the visible light spectrum?
Red, orange, yellow, green, blue, indigo, violet
336
In terms of other colours, what is white light?
A mixture of all of the colours of the spectrum
337
If white light passes through a transparent prism, what happens to it?
It refracts into the different colours of the spectrum
338
Why is light split into a spectrum of colours by a prism?
Because different colours refract by different amounts
339
Explain why blue objects appear blue.
They reflect blue light and absorb all other colours of light.
340
Explain why white objects appear white.
They reflect all colours of light equally.
341
What does a planet orbit?
A star
342
What does a moon orbit?
A planet
343
What is the name of the Earth’s star?
The Sun
344
What is the Sun?
The star closest to Earth
345
In what three ways can stars be different from one another?
Stars can be very different in terms of size, age and temperature
346
Name the elliptical path that planets take around stars (and moons take around planets).
An orbit
347
What force causes an object to orbit another object?
Gravity
348
Name the planets in our solar system in order from closest to the Sun to furthest from the Sun.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
349
What is Pluto?
A dwarf planet
350
Name the biggest planet in our solar system.
Jupiter
351
What is a galaxy?
A collection of millions of stars (and their orbiting planets and moons)
352
What is the name of our galaxy?
The Milky Way
353
Why do we need the unit of light years?
Because astronomical distances are so large
354
What is a light year?
The distance that light can travel in one year
355
Why do we get day and night?
Because the Earth spins on its axis
356
Why do we get seasons?
Because the Earth orbits the Sun on a tilted axis
357
What are the names of the two hemispheres of Earth?
The northern hemisphere and the southern hemisphere
358
When it is summer in the northern hemisphere, what season is it in the southern hemisphere?
Winter
359
When does the northern hemisphere experience summer?
When the northern half of the Earth’s axis is tilted towards the Sun
360
When does the southern hemisphere experience summer?
When the southern half of the Earth’s axis is tilted towards the Sun
361
Why are days shorter in winter?
Because of the tilt of the Earth, we face the Sun for less time in winter
