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Science > Yr 9 Yearlys > Flashcards

Yr 9 Yearlys Flashcards

1
Q

How is heat energy transferred through solids by conduction?

A

The heat is transferred through particles

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2
Q

How is heat energy transferred through fluids by convection?

A

The hot fluids rise whilst the cooler fluids move down. The space left by the hot fluids is then filled by the cooler ones and the cycle continues.

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3
Q

How is heat energy transferred through empty space by radiation?

A

Through invisible waves travelling at the speed of light from the sun (infrared radiation)

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4
Q

Conductors of heat: Metal?

A

It is a good conductor of heat and transfers heat easily.

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5
Q

Conductors of heat: Wood?

A

It is a bad conductor of heat and a good insulator.

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6
Q

Conductors of heat: Plastic?

A

It is a poor conductor of heat and an insulator.

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7
Q

Define a wave

A

A movement of energy without a net movement of mass.

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8
Q

Longitutinal waves

A

The particles that make up the wave move back and forth in the same direction as the wave is travelling

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9
Q

Transverse waves

A

The particles move perpendicular to the direction of disturbance.

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10
Q

Sound waves

A

A longitudinal wave travelling through air

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11
Q

Compressions

A

Regions of space in a wave where the particles are bunched together.

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12
Q

Rarefactions

A

Regions of space in a wave where the particles are more spread out

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13
Q

Wavelength

A

The distance between successive peaks of a wave. Measured in metres.

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14
Q

Frequency (sound)

A

The number of vibrations a sound makes per second. Measured in hertz.

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15
Q

Explain the relationship between a sound’s wavelength and frequency

A

Waves have a constant speed but if the frequency increases then the wavelength decreases.

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16
Q

How is sound caused in the air?

A

When an object is vibrating it passes its vibrations into the surrounding areas. The sound ripples away from the object. They move in the form of a longitudinal wave.

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17
Q

How does sound travel through each of the mediums

A

Sound travels through different mediums at different speeds:
Gases - Sound waves travel the slowest
Liquids - Sound waves travel faster
Solids - Sound waves travel the fastest

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18
Q

Give the order of events that allow you to hear

A

First: Your ears collect soundwaves as they enter the outer ear and travel through the ear canal.
Second: Vibrations of the sound wave strike the eardrum, causing it to vibrate.
Thirdly: The vibrations are passed on to the three tiny bones of the middle ear, where they are converted into electrical impulses.
Finally: your brain interprets the impulses as sound.

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19
Q

What is the law of reflection:

A

The law of reflection states that the angle of incidence of a light ray is equal to the angle of reflection.

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20
Q

What are the incidence ray, reflected ray and line of normal?

A

The incidence ray is the ray of light travelling from the object to the reflective surface, such as a mirror. The reflected ray is the ray travelling from the reflective surface to your eyes.
The line of normal is always at the right angle.

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21
Q

Explain Refraction

A

The bending of light. Light refracts when it travels through one transparent substance into another at a different speed. This is because light travels at different speeds through different substances.

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22
Q

What is the frequency of a wave

A

The number of waves produced each second and is measured in hertz.

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23
Q

Amplitude of a wave

A

The maximum distance a wave extends from its middle position. The larger the amplitude of the wave is, the more energy it has.

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24
Q

Wave equation

A

The wave equation is if the frequency of a wave increases - the wavelength decreases. If the frequency decreases the wavelength will increase.

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25
Q

The electromagnetic spectrum in terms of wavelength and frequency

A

As the energy of radiation increases, the frequency increases and the wavelength decreases.

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26
Q

Visible spectrum

A

The visible spectrum is the part of the electromagnetic spectrum that is visible to the human eye and consists of colours. When these colours are combined they create white light.

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27
Q

How is the colour of an object determined?

A

Determined by which colours of the spectrum are reflected and absorbed.

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28
Q

What are the primary and secondary colours of light?

A

The primary colours: Red, green and blue
The secondary colours: Cyan, magenta and yellow.

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29
Q

What happens when the primary colours are shone together?

A

White light is produced.

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30
Q

How do colour filters work?

A

A colour filter only allows the light of its specific colour to pass through it.

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31
Q

What are the uses of radiowaves

A

Used by television and radio networks to transmit signals. Short-wave and long-wave radio waves are also used in communications.

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32
Q

What are the sources, properties and uses of a microwave?

A
  • Also used in communication and radar systems
  • Microwaves are absorbed by fats, sugars and water, causing food molecules to vibrate and heat up.
  • Glass, paper and many plastics don’t absorb microwaves, and metal reflects microwaves.
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33
Q

What is an infrared ray?

A

The heat transferred from the Sun to the Earth

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34
Q

Infrared ray properties:

A
  • It is below red on the visible spectrum and has a lower frequency than it.
  • It cannot be seen, however, it is felt as warmth.
  • Every object with a temperature over absolute 0 emits infrared rays.
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35
Q

What is an analogue signal and how is it transmitted?

A
  • Some mediums, like copper wires connected to landline phones, are designed to carry an analogue signal.
  • The voltage of an analogue signal is determined by the speaker’s voice.
  • Analogue signals are limited because they develop signal loss and interference as they travel.
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36
Q

What is a digital signal and how is it transmitted?

A
  • Communication systems like the tv and internet require a digital signal.
  • A modem connects a computer to a telephone line and converts the digital signal into an analogue signal that the phone line transmits. (modulation)
  • A digital signal can still be read when interference disrupts the signal.
37
Q

What is UV light?

A

Ultraviolet light is radiation with a higher frequency than violet.

38
Q

What are the properties and uses of UV light?

A
  • Sunlight contains UV rays
  • The human body needs some exposure to UV rays, and it cannot be seen.
  • Higher exposure to UV rays can cause skin cancers and cataracts in the eyes.
  • Some substances turn fluorescent when exposed to UV, meaning they absorb UV and emit visible light. Some white paper, teeth whiteners and laundry powders utilize this to make the white brighter. It is also used as a steriliser.
38
Q

How is an X-ray produced?

A

When accelerating electrons collide with a target. Slowing them down releases the x-rays.
They require high voltage to be produced

39
Q

Properties of an X-ray:

A

They travel in a straight line, don’t carry an electric charge with them, can’t be deflected by electrical fields or magnetic fields, and have a high penetrating power.

40
Q

X-ray uses

A
  • They are used to show doctors what is inside the body. Types include mammograms, dental and fluoroscopy.
  • Some industrial uses include checking oil and gas pipelines, and testing vehicle parts and aircraft parts.
41
Q

What are gamma rays?

A

Rays with high-energy electromagnetic radiation which is produced by radioactive materials.

42
Q

What are gamma-ray properties?

A
  • They have wavelengths of about one hundred billionths of a metre
  • Have the ability to free electrons from their atoms and therefore make ions.
43
Q

What are the uses of gamma rays?

A
  • Used in medicine as radiotherapy and to disinfect and sterilise medical equipment
  • Also used in the nuclear industry
44
Q

Diffusion

A

Diffusion is the movement of particles of a substance from an area of high concentration to an area of low concentration. It occurs in liquids and gasses.

45
Q

What is the role of the nervous system?

A

The nervous system is a system that acts as a communication network which controls all the other systems in the body.

46
Q

What is the central nervous system?

A
  • Is made up of the brain and the spinal cord
  • Receives information from all over the body, processes that information, and then sends out messages telling the body how to respond.
47
Q

What is the peripheral nervous system?

A

The nerves that carry messages to and from the central nervous system and other parts of the body.

48
Q

Define a reflex action

A

When touching something hot or sharp, you automatically pull your hand away, this is involuntary and does not wait for the brains instructions.

49
Q

Explain how the reflex arc works

A

1st: Receptors detect the temperature of your skin.
2nd: Activates a sensory neuron, which sends nerve impulses to the spinal cord
3rd: A relay neuron passes the info to a motor neuron in the spinal cord
4th: Sends impulses to the arm muscles, causing the arm to contract away.
5th: Only then can the brain register the pain.

50
Q

Cerebrum:

A
  • Occupies more than 80% of the brain and contains over 10 billion neurons
  • Higher intellectual functions of humans take place here
  • Controls your conscious thoughts and voluntary movements
  • Receives sensory messages from all parts of the body
51
Q

What are the two sides of the cerebrum?

A

The cerebrum is split into two halves, the right and left hemispheres. The left hemisphere of the brain controls the right side of the body and the right side controls the left side.

52
Q

Cerebellum

A

It is responsible for coordination and balance

53
Q

Brain stem

A
  • It can be seen where the spinal cord widens after it passes into the skull.
  • It connects the brain to the spinal cord.
  • Controls the body’s vital functions, such as breathing, blood pressure, digestion and heart rate.
54
Q

Ecosystem

A

A place where the organisms and their physical surroundings form an environment that is different from environments nearby.

55
Q

Examples of ecosystems:

A

Rainforests, ponds, rivers, deserts, tundra, coral reefs and grasslands.

56
Q

Biotic

A

A living factor. These include predators, prey, parasites, fungi, infectious organisms and collaborators.

57
Q

Abiotic

A

A non-living factor, which is also known as a physical factor. These include air quality, humidity, the amount of sunlight, rainfall, wind, tides, waves, lightning and fire.

58
Q

Competition

A

Organisms compete for resources, which may only exist in limited quantities.

59
Q

Predation

A

When one organism kills and eats another, the attacker is called the predator and the one being eaten is called the prey.

60
Q

Mutualism

A

A relationship between two organisms who live closely together and both benefit.

61
Q

Parasitism

A

One organism (the parasite) lives in or on another organism (the host) and feeds off it. The parasite cannot survive without the organism in which it lives.

62
Q

Commensalism

A

Is a relationship in which one organism benefits and the other is unaffected.

63
Q

Producers and give examples:

A

Producers are organisms that make their own food (autotrophs)
Examples include plants, e.g. trees, ferns and moss.

64
Q

Word equation for photosynthesis

A

Carbon dioxide + water Light glucose + oxygen
———–>
Chlorophyll

65
Q

Construct a food chain

A

Producer: e.g. grass, the food materials are made by this.
First order consumer: e.g. grasshopper, eats the grass containing food materials.
Second order consumer: e.g. frog, eats the grasshopper containing food materials.
Third-order consumer: e.g.s snake, eats the frog and gains the food materials.
All of these organisms use the food to sustain and maintain their bodies.

66
Q

Food chain

A

A sequence of organisms feeding on eachother.

67
Q

Food webs

A

There are many food chains in ecosystems and they are all interconnected. All the connected food chains are known as a food web. Food webs are usually complex, with each organism appearing in many different food chains.

68
Q

How does energy flow through an ecosystem?

A

Energy flows continuously through the ecosystem being lost as fast as it is gained. It flows from one organism to another as it is eaten.

69
Q

Define biodiversity

A

Refers to the range of different species in a community.

70
Q

What are the human impacts:

A

Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water.

71
Q

What are microplastics and where are they found?

A

Microplastics can be found everywhere, even in tap water. The surfaces of the tiny fragments of plastic may carry disease-causing organisms and act as a vector for diseases in the environment. Microplastics can also interact with soil fauna, affecting their health and soil functions.

72
Q

Strategies to minimise negative human impacts:

A

To minimise human impact on biodiversity try to walk, cycle or use public transport. Bring fabric bags when shopping to minimise waste. Separating waste into different sections also supports material recovery.
Bring food from home.

73
Q

What are the spheres of the earth

A

The earth has four spheres, the lithosphere (surface land), the hydrosphere (water), the atmosphere (air) and the biosphere (living things)

74
Q

What are the Earths layers

A

Earth has four layers, the inner core (solid) and outer core (liquid), the mantle (magma) and the crust.

75
Q

Outline Alfred Wegener’s reasoning behind plate tectonics

A
  • By looking at how the continents fit together like puzzle pieces
  • Fossils from the same species of dinosaur could be found on different continents.
76
Q

How many plates are on the earth?

A

There are 15 major plates. Many of these are split into smaller plates, they are differing sizes.

77
Q

Oceanic crust

A

Found on the ocean floor, generally below sea level. It is darker and thinner than the continental crust. It is also denser (less silicon and more of heavier materials like iron and magnesium)

78
Q

Continental crust

A

The crust forming at the continents and projects above sea level.
Has a lot of aluminium and silicon.

79
Q

Diverging boundaries

A

constructive boundaries - the crust is being created
plates are moving apart, leaving a rift, magma rises and creates new crust.

80
Q

Converging boundaries

A

destructive boundaries - crust is being destroyed
plates are colliding with each other, rock is destroyed.
form land features such as mountains, underwater trenches and island chains.

81
Q

Transform boundaries

A

conservative boundaries - crust is neither created nor destroyed. plates are sliding parallel to each other in opposite directions.
usually move very slowly past each other but then may suddenly slip. usually has fold mountains along its length, and cracks in the rock called fault lines (many paralell)

82
Q

What is theory of plate tectonics

A

States that major landforms are created as a result of Earth’s subterranean movements. This means that Earth’s continents were created as a result of continental drift

83
Q

Seafloor spreading

A

A new rocky crust being formed at the ocean ridges and spreading outwards.

84
Q

Subduction

A

Earth’s crust sinking into the mantle creating ocean trenches.

85
Q

How seafloor spreading supports the theory of plate tectonics

A

When the seafloor spread and the tectonic plates shifted, that left the seafloor in the middle to be newer than the countries that are further away. Seafloor spreading shows how it’s moving outwards.

86
Q

Why diverging and converging boundaries produce volcanoes

A
  • When converging boundaries slide underneath each other subduction occurs, the crust is destroyed and the magma rises. Crust dries with magma inside forming a volcano.
  • When diverging boundaries move away they create space from which magma can rise from. As they are usually underwater they are less violent than convergent boundaries.
87
Q

How is a tsunaminami formed?

A

Caused by earthquakes and slabs under the sea floor moving and creating energy. This displaces the ocean into long overlying waves that move outward in all directions from the epicentre.

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