Science Flashcards
(161 cards)
1
Q
Name 3 uses for artificial satellites/probes
A
Communication, monitoring conditions on Earth, exploring the solar system
2
Q
How are other planets visible?
A
Light from the Sun is emitted in all directions. Some light reflects off the surface of planets and travels to Earth (and into our eyes)
3
Q
What force keeps planets in orbit around the Sun and the Moon in orbit around Earth?
A
Gravity
4
Q
In what direction does Gravity act?
A
Towards the centre of a mass
5
Q
What equation links gravity, weight and mass?
A
Weight = Mass x G
6
Q
What is the gravitational field strength on Earth?
A
10N/Kg
7
Q
Excluding Pluto, name the order of the planets in the solar system (closest to Sun first)
A
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
8
Q
What is the name of Earth’s natural satellite?
A
The Moon
9
Q
What’s the name of the galaxy our solar system is part of?
A
The Milky Way
10
Q
What is the Universe made up of?
A
Many millions of groups of stars or galaxies
11
Q
What is a light-year?
A
The distance light travels in one Earth year (travelling at 300,000,000 m/s)
12
Q
What is the cause of day and night on Earth?
A
The rotation of the Earth on its axis (once every 24 hours)
13
Q
What is the cause of the seasons on Earth?
A
Earth’s axis is tilted at 23.5 degrees. This means that at any one time, one hemisphere is tilted towards the Sun
14
Q
When does a solar eclipse occur?
A
When the moon’s orbit places it directly between Earth and the Sun, blocking light from the Sun reaching one part of the Earth.
15
Q
When does a lunar eclipse occur?
A
When the Moon is in the shadow of the Earth.
16
Q
What is the length of the Moon’s orbit around the Earth?
A
28 days, which leads to the phases of the Moon (e.g. New Moon, Full Moon).
17
Q
What is created when a current flows through a coil of wire?
A
A magnetic field similar to that of a bar magnet.
18
Q
How can we visualize an invisible magnetic field?
A
By using plotting compasses or iron filings.
19
Q
What are some of the uses of electromagnets?
A
- Lifting magnets (scrap yard)
- Relays
- DC motors
20
Q
How do the poles of two different magnets interact?
A
Like poles repel each other, unlike poles attract.
21
Q
In what direction does a magnetic field flow?
A
From North to South (shown with arrows).
22
Q
What energy transfers happen in a battery/cell?
A
Chemical energy to electrical energy, then electrical is converted into other forms by components.
23
Q
What is the name of the unit of electrical current?
A
Ampere (Amp).
24
Q
What device measures current and how should it be placed in a circuit?
A
An ammeter - always placed in series.
25
How can current be defined?
The rate of flow of charge in a circuit.
26
How does current behave in series and parallel circuits?
* Series: same everywhere
* Parallel: splits between the branches of the circuit.
27
What is an insulator?
A material that has a very high resistance.
28
What is a conductor?
A material with a very low resistance.
29
What does LDR stand for?
Light Dependent Resistor.
30
What is the relationship between resistance and light intensity with an LDR?
The higher the light intensity, the lower the resistance (the larger the current).
31
What is the relationship between resistance and temperature with a Thermistor?
The higher the temperature, the lower the resistance (the larger the current).
32
How do you find the volume of a regularly shaped object?
L x W x H
33
How do you find the volume of an irregularly shaped object?
Water displacement (put object in cylinder with water, measure new volume of water, minus new volume from original volume)
34
What is the equation for calculating pressure?
P = F / A
35
Name 2 commonly used units for pressure
* N/m² (Pa)
* N/cm²
36
What is the result of a large force on a small area?
A very large pressure
37
Name 2 forces that act against a moving object
* Friction
* Air resistance (Drag)
38
What can affect a car's stopping distance?
* The surface of the road
* The speed of the car
* The reaction speed of the driver
39
What can unbalanced forces do to a moving object?
Change its speed and/or direction
40
What is the overall force (and direction) acting on an object called?
The resultant force
41
If all the forces on an object are balanced, what will be the value of the resultant force?
0 (Zero) N
42
What 'e' word describes balanced forces?
Equilibrium
43
How can forces be represented on a diagram?
With arrows that show the direction and size of the force
44
If the forward force (thrust) increases on a moving object and all other forces stay the same, what will the object do?
Accelerate
45
What does a straight, diagonal line upwards mean on a distance-time graph?
Constant speed
46
What does a straight, horizontal line mean on a speed-time graph?
Constant speed
47
Using a speed-time graph, how can you calculate the distance travelled?
By working out the area under the line
48
Complete the Law of Conservation of Energy: Energy cannot be...
Created or destroyed, but can be transferred from one store to another
49
Name the 7 energy stores
* Gravitational
* Electrical
* Thermal
* Nuclear
* Elastic
* Chemical
* Kinetic
50
What is special about diodes (e.g. LEDs)?
They only allow current to flow in one direction.
51
Why do appliances have fuses?
So that the fuse blows (wire inside breaks) if the current gets too high - which prevents electrical fires.
52
What is the difference between a cell and a battery?
A battery is made up of 2 or more cells in series.
53
What is dispersion of light?
When white light is split into a spectrum of colours (each with a different frequency) by an object such as a prism.
54
In what order does light always disperse?
Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROY G BIV).
55
What is refraction?
Light changing direction when it reaches a boundary between two different media.
56
When light passes, at an angle other than 90 degrees, from air to glass, which way will it bend?
It will bend towards the normal since glass is more dense than air.
57
What is the Law of Reflection?
Angle of incidence = angle of reflection.
58
How is an angle of incidence measured?
From the ray of light to the Normal line.
59
How do we see non-luminous objects?
Light reflects off non-luminous objects and some of this light enters our eyes.
60
How does light travel?
In straight lines, at 300,000,000 m/s and can travel through a vacuum.
61
In what units do we measure the frequency of sound?
Hertz (Hz).
62
What does frequency refer to when discussing sound?
The pitch (high frequency = high pitch).
63
What can happen to humans when exposed to sounds above 120 dB?
Permanent hearing damage.
64
What is the range of hearing of humans?
20 - 20,000 Hz.
65
What does the amplitude of a sound wave refer to?
The loudness/volume of a sound.
66
How is amplitude measured?
In metres - and is the length between the normal line and the peak of a wave.
67
Through which material does sound travel the fastest?
Solids (as they are generally more dense than liquids and gases).
68
What is the equation for Density?
D = M / V.
69
Name 2 appropriate units for density.
* g/cm³
* Kg/m³
70
Name the 5 energy pathways
Mechanical, electrical, radiation (light and sound), chemical reaction, heating
71
What is the unit for energy?
Joule (J)
72
What is the ultimate source of all energy on the planet?
The Sun
73
How did fossil fuels form?
Plant and animal remains buried by layers of mud and silt, and experienced heat and pressure
74
What are the 3 fossil fuels?
Coal, Oil, Natural Gas
75
Name 2 advantages of renewable energy resources
Can be replenished in a lifetime, Do not emit harmful gases such as CO₂ and SO₂
76
Name 2 advantages of non-renewable energy resources
They burn efficiently producing a lot of heat energy, They are relatively inexpensive compared to some renewable energy resources
77
Name 3 negative effects of acid rain
Corrosion of limestone structures, Acidification of soils (lime needed), Acidification of lakes and rivers
78
Which gas causes the formation of acid rain?
Sulphur dioxide (SO₂)
79
What pH are metal oxides?
pH > 7
80
What pH are non-metal oxides?
pH < 7
81
What would blue and red litmus paper do if you dipped them into NaOH?
Blue would stay blue, Red would turn blue
82
What colour would be observed if Universal Indicator was placed in HCl?
Red/Orange
83
Fill in the blank: Acid + Base = _______
Salt + water
84
Fill in the blank: Acid + Metal = _______
Salt + Hydrogen
85
Fill in the blank: Acid + Metal Carbonate = _______
Salt + water + carbon dioxide
86
Name 2 chemical tests for water
Anhydrous copper sulphate (white to blue), Cobalt chloride (blue to pink)
87
What is the chemical test for hydrogen gas?
Lit splint # squeaky pop
## Footnote
This test indicates the presence of hydrogen gas by producing a distinctive sound.
88
Why are metals such as potassium never found in their elemental state?
They are too reactive and so only found in compounds
## Footnote
Highly reactive metals readily combine with other elements, preventing them from existing in their pure elemental form.
89
How is iron extracted from iron ore?
By reacting iron oxide with carbon in a blast furnace to produce carbon dioxide and iron
## Footnote
This method is a common industrial process for obtaining iron from its ore.
90
What is the order of the Metal Reactivity Series?
K, Na, Li, Ca, Mg, Al, C, Zn, Fe, H, Cu, Ag, Au
## Footnote
This series ranks metals based on their reactivity, with potassium being the most reactive.
91
What uses of copper are related to its reactivity?
Does not rust (water pipes), Can conduct electricity (electrical wiring)
## Footnote
Copper's low reactivity makes it ideal for applications where corrosion resistance is important.
92
What would happen in a reaction between sodium chloride and iron?
Iron would displace sodium in sodium chloride
## Footnote
This is a typical single displacement reaction due to iron's higher reactivity compared to sodium.
93
What products would be formed if potassium reacted with zinc sulphate?
Potassium sulphate and zinc
## Footnote
Potassium's strong reactivity allows it to displace zinc in this reaction.
94
Why are gold and silver so expensive?
They have a very low reactivity which means they retain their lustre (shine) for a long time
## Footnote
The low reactivity contributes to their desirability and value.
95
What 2 conditions are needed for iron to rust?
Presence of oxygen and water
## Footnote
Rusting is an electrochemical process that requires both elements to occur.
96
What percentage of air is oxygen?
21%
## Footnote
Oxygen is a major component of the Earth's atmosphere, essential for combustion and respiration.
97
If the compound potassium permanganate breaks down into products with heat alone, what type of reaction is it?
Thermal Decomposition
## Footnote
This type of reaction involves breaking down a compound into simpler substances using heat.
98
What 2 products are always formed when any fuel (sugar, oil, coal, natural gas) is burnt?
Carbon dioxide and water (and heat)
## Footnote
Combustion reactions typically yield these products along with energy.
99
What is the chemical test for oxygen?
Glowing splint B relights
## Footnote
This test demonstrates the presence of oxygen, as it reignites a glowing splint.
100
What is the chemical test for carbon dioxide?
Bubble through limewater # turns cloudy/milky
## Footnote
This test indicates carbon dioxide presence through the formation of calcium carbonate.
101
How is a Bunsen flame described when the air hole is closed?
Lower temperature, yellow/visible, known as safety flame
## Footnote
This type of flame is less efficient and produces soot.
102
How is a Bunsen flame described when the air hole is open?
Higher temperature, used for strong heating, known as roaring flame
## Footnote
This flame is more efficient for heating due to complete combustion.
103
What products are formed when copper oxide is heated strongly with magnesium?
Magnesium oxide + copper
## Footnote
This reaction demonstrates the ability of magnesium to reduce copper oxide.
104
What is meant by conservation of mass?
In a chemical reaction, the total mass of reactants is always equal to the total mass of products
## Footnote
This principle underlies the law of conservation in chemistry.
105
What is a solute?
A soluble substance added to a solvent to make a solution
## Footnote
Solutes can be solid, liquid, or gas that dissolve in a solvent.
106
What name is given to a solution that contains the maximum amount of a solute?
Saturated
107
How does solubility vary with temperature?
In general, as temperature of a solvent increases, so does the solubility of substances in it
108
Which method of separation relies on different boiling points?
Simple/Fractional distillation
109
Where is cold water put into a Liebig condenser?
At the bottom (furthest from the Bunsen)
110
How is an insoluble solid recovered from a mixture containing a liquid?
Filtration
111
What is the name of a solid left on filter paper after filtrations?
Residue
112
What is the boiling and melting point of pure and impure water?
Pure: 100 and 0 degrees C; Impure: >100 and <0 degrees C
113
Outline the composition of the atmosphere
N2 = 78%, O2 = 21%, CO2 = 0.04%, Other gases and water vapour = 1%
114
How are metals described?
Hard, Shiny, High mpt/bpt, malleable, ductile, sonorous, good conductors of heat and electricity
115
What is an atom?
The smallest unit of matter
116
What is an element?
A substance made up of only one type of atom (there are approx. 100 types)
117
What is a compound?
2 or more different elements chemically combined
118
What is a molecule?
A group of atoms chemically combined (e.g. O2, C6H12O6)
119
Name the changes of state from solid to gas and back again
Melting, boiling, condensation, solidification
120
What is the name of the change of state from a solid to a gas?
Sublimation
121
How do gas particles create pressure when in a container?
Particles move in random directions and collide with the inner surface of the container. Pressure is the sum of the forces of the collisions
122
What are the 5 major kingdoms that all life is divided into?
Plants, Animals, Bacteria, Fungi, Single-celled organisms
123
How is the animal Kingdom divided into 2 main groups?
Vertebrates and invertebrates
124
How is the vertebrate group divided?
Mammals, amphibians, birds, fish and reptiles
125
What are the main characteristics of mammals?
Fur/Hair, give birth to live young, feed young with milk
126
What are the main characteristics of amphibians?
Breathe through skin and lungs, moist skin, lay eggs
127
In humans, what are examples of inherited variation?
Blood group, hair colour, eye colour
128
In humans what are examples of environmental variation?
Accent, scars
129
What is discontinuous variation?
Variation that can be classified into groups e.g. blood group: A, B, AB, O (only)
130
What is continuous variation?
Variation that can be placed on a numerical scale e.g. height, weight
131
What are the 2 main factors that can influence a population size?
Predation and competition for resources
132
Name 3 ways to collect samples when studying a population.
* Pooters
* Pitfall traps
* Quadrats
133
What do the arrows in a food chain represent?
The flow of energy along the chain (each trophic level)
134
Explain what producers, herbivores, and carnivores are.
* Producers: carry out photosynthesis
* Herbivores: primary consumers (eat producers)
* Carnivores: secondary and tertiary consumers (eat primary consumers)
135
Which 2 processes that living organisms carry out maintain a natural balance of the carbon cycle?
Photosynthesis and respiration
136
What is the equation for anaerobic respiration in humans?
Glucose → Lactic acid + energy
## Footnote
Anaerobic respiration occurs in the absence of oxygen and produces lactic acid as a byproduct.
137
What is the equation for anaerobic respiration in yeast?
Glucose → Ethanol + CO2
## Footnote
This process is also known as fermentation, which is utilized in brewing and baking.
138
In cells, where does respiration take place?
Mitochondria
## Footnote
Mitochondria are known as the powerhouse of the cell where aerobic respiration occurs.
139
How are root hair cells specialised for their function?
They have a protrusion which vastly increases the surface area to absorb water
## Footnote
This adaptation helps in maximizing water and nutrient uptake from the soil.
140
How do plants transport water from roots to leaves?
Through vessels called the Xylem
## Footnote
Xylem transports water and dissolved minerals from the roots to the rest of the plant.
141
Which mineral do plants need to absorb from the soil to make chlorophyll?
Magnesium
## Footnote
Without magnesium, plants may exhibit yellowing of leaves due to insufficient chlorophyll production.
142
Name the layers of a leaf from the top surface to bottom surface.
Waxy cuticle, Upper epidermis, Palisade, Spongy mesophyll, Lower epidermis
## Footnote
These layers play specific roles in protecting the leaf and facilitating photosynthesis.
143
What is the function of the stomata?
To allow CO2 into the leaf (for photosynthesis)
## Footnote
Stomata are small openings on the leaf surface that regulate gas exchange.
144
Why is elodea a good plant to use to study the rate of photosynthesis?
Being an aquatic plant, the oxygen produced can be seen/counted as bubbles
## Footnote
This visual representation allows for easy measurement of photosynthesis rates.
145
What does a plant do with the glucose made during photosynthesis?
1) Converts into starch for storage
2) Makes cellulose cell walls
3) For respiration (day & night)
## Footnote
These processes are crucial for plant growth and energy management.
146
Name a bacterial and viral infection.
Bacterial: Meningitis; Viral: Influenza
## Footnote
Meningitis is an infection of the protective membranes covering the brain and spinal cord, while influenza is a common viral infection affecting the respiratory system.
147
What are the body's natural defences against harmful microbes?
Skin, mucus, white blood cells
## Footnote
These components work together to prevent infections and respond to pathogens.
148
What are the main harmful chemicals in cigarette smoke and what do they do?
Nicotine - addictive; Tar - reduces efficient gas exchange and can cause cancer; Carbon monoxide - reduces the ability of red blood cells to carry oxygen
## Footnote
These chemicals contribute significantly to health issues associated with smoking.
149
What are the main negative effects of alcohol on the human body?
Liver cirrhosis (permanent damage); Addiction; Very poor reaction speeds/impaired judgement
## Footnote
Chronic alcohol consumption can lead to severe health problems and impair cognitive functions.
150
What 3 parts of a flower constitute the female organs?
Carpel - Ovary, style & stigma
## Footnote
These structures are essential for reproduction in flowering plants.
151
What are the male parts of a flower called?
Anther and filament
## Footnote
These components make up the stamen, which is responsible for pollen production.
152
What is pollination?
Transfer of pollen from an anther to a stigma of a flower of the same species
153
What does the pollen do when it lands on a stigma of the same species?
It creates a tube down the style for the nucleus to reach the ovary
154
What is fertilisation in plants?
When the nucleus of the pollen grain fuses with the nucleus of an ovule
155
What does the fertilised ovule in a plant become?
The seed - with the ovary swelling to form the fruit
156
What 2 mechanisms are used for pollination?
* Insects
* Wind
157
What are the features of a wind-pollinated flower?
* Small, dull petals
* Feathery stigma
* Stamen dangling outside flower
* Large amounts of light pollen
* No nectary
158
Why is it important for seeds to be dispersed away from the parent plant?
To reduce competition for light, water, nutrients, space between the parent and offspring plant
159
What mechanisms can be used for seed dispersal?
* Water
* Wind
* Animal
* Self
160
What are the conditions required for a seed to germinate?
* Water
* Oxygen
* Warmth
161
What are the three main parts of a seed?
* Seed coat
* Embryo
* Food store
