Yearly science
Definition of Waves: A disturbance or variation that carries energy progressively from point to point in a medium and that may take the form of an elastic deformation or of a variation of pressure, electric or magnetic intensity, electric potential, or temperature.
Waves are categorized in two different groups
Mechanical or Electromagnetic
Mechanical Waves:the energy is transferred by vibrations of medium (medium = matter)
They are split in two types of waveforms which are Transverse and Longitudinal
Transverse: The motion in which all points on a wave oscillate along paths at right angles to the direction of the wave's advance.
Examples of transverse waves
Water ripples
rope
Light
Earthquake
Longitudinal: a type of wave in which the medium's vibration is parallel to the direction of the wave, and the medium's displacement is in the same direction as that of the wave movement. Such as sound waves vibrating surface in contact with air.
Examples:
Sound
Slinky
Properties of Transverse Waves
The wavelength of a wave is the distance from one point of the wave to the next identical point of the wave.(Measured in cm or m)
The period of a wave is the time it takes one wave to pass a point
The frequency of a wave is the number of wavelengths that pass a point each second.
The energy carried by a wave depends on its frequency and amplitude. The higher the frequency the larger amplitude, the more energy the wave carries.The amplitude of a wave is the distance from the zero displacement position of the matter particles to a maximum displacement position (a crestbloo or trough). Measured in cm or m.
The zero displacement position indicates where the particles would be if no energy was being transferred through the medium.
A crest is the position of maximum upward displacement of a particle-the “top of the wave”
A trough is a position of maximum downward displacement of a particle- the “bottom of the wave
Properties of Longitudinal Waves
The wavelength of a wave is the distance from one point of the wave to the next identical point of the wave.(Measured in cm or m)
The period of a wave is the time it takes one wave to pass a point
The frequency of a wave is the number of wavelengths that pass a point each second.
The energy carried by a wave depends on its frequency and amplitude. The higher the frequency the larger amplitude, the more energy the wave carries.The amplitude of a wave is the distance from the zero displacement position of the matter particles to a maximum displacement position . Measured in cm or m.
The zero displacement position indicates where the particles would be if no energy was being transferred through the medium
Both rarefactions and compressions are positions of zero displacement in a longitudinal wave.
In a longitudinal wave, the direction ofthe movement of particles in matter is back and forth along the direction of the transfer energy.
How to Calculate Waves
Velocity=Speed
Frequency:Hertz (Hz)
Wavelength: Distance (cm or m)
Electromagnetic Waves
Electromagnetic Specturm:
KEY POINTS ON ELECTROMAGNETIC WAVES
The electromagnetic (EM) spectrum is the range of all types of EM radiation.
All electromagnetic waves travel at the same speed – the speed of light.
The property that makes electromagnetic waves behave differently is their wavelength. This is related to how much energy they transfer from one place to another: the shorter the wavelength, the higher the energy. For example, X-rays have very short wavelengths and very higher energy. In contrast, radio waves have long wavelengths and low energy.
Uses of Electromagnetic radiation
Radio Waves:Television,Phones and Wi-Fi
Micro Waves:Microwave Ovens, Radars, Satellite communication
Infrared Waves:Remote Controls,Thermal Imaging, Heating
Visible light: Human vision, Illumination, photography and videography.
Ultraviolet Waves: Sterilization, Tanning, forensics
X-rays:Medical Imaging, Security screening
Gamma Waves: Astrophysics, Cancer treatment, Nuclear medicine21
LIGHT:
Light is a type of energy. Unlike sound, light can travel through space even where there is no matter.
Reflection of Light:
Light always travels through air at the same speed and in a straight line. When light hits an object, some of it bounces or reflects off the surface. The type of surface determines how the light reflects:
Uneven or rough surfaces reflect light rays in different directions. This scattering of light is called diffuse reflection.
In contrast, smooth, shiny surfaces reflect light rays in a regular pattern. This allows us to see a clear image reflected back at us and is called regular reflection. Mirrors are a great example of this.
Law of reflection
The way a light ray reflects off a surface follows a simple pattern. The incoming ray is called the incident ray. To work out the direction of the reflected ray, we can think of a line at right angles to the surface. This line is called the normal. As shown in the diagram below:
The angle between the incident ray and the normal is called the angle of incidence.
The angle between the reflected ray and the normal is called the angle of reflection.
Lenses
A lens is a curved piece of transparent glass or plastic that refracts light. Since a lens is curved on at least one side, light rays striking different parts of its curved surface change direction by different amounts.
Depending on the shape of the lens the light can either:
Get further apart, or diverge
Get closer together, or converge
Concave Lenses
A lens that is curved inwards and is thinner in the middle is called a concave lens.
Concave lenses cause parallel light rays to diverge, or spread out. Because the rays diverge in this way they appear to an observer to come from one point. This is called the focal point.
The distance from the focal point to the centre of the lens is called the focal length.
Convex Lenses
A lens that is curved outwards and is thicker in the middle is called a convex lens.
Convex lenses cause parallel light rays to converge, or get closer together. The point where parallel rays converge is called the focal point. Just as for concave lenses, the distance between the focal point and the centre of the lens is the focal length.
independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure.
dependent variable is the variable that changes as a result of the independent variable manipulation. It's the outcome you're interested in measuring, and it “depends” on your independent variable.
A control variable is anything that is held constant or limited in a research study.
ECOSYSTEMS
An ecosystem is a geographic area where plants, animals and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living parts, as well as abiotic factors, or nonliving parts.
Examples of Abiotic and Biotic Factors
Levels of Ecology
Organism: An individual living being that can be a plant, animal, or microorganism
Population: A group of individuals of the same species living in a particular area at the same time.
Community: A group of different species living together in a specific area and interacting with each other.
Biome:A large region defined by similar climate, vegetation, and animal life, such as forests, deserts, and grasslands.
Ecosystem: A community of living organisms interacting with their physical environment (e.g., forests, lakes).
Biosphere: The global sum of all ecosystems, encompassing all living organisms and their environments.
Food Chains/Web
A food chain is a linear sequence of organisms that shows how energy and nutrients flow from producers to consumers in an ecosystem.
A food web is a complex network of interconnected food chains that illustrates how various organisms in an ecosystem are related through their feeding relationships.
Primary consumers: are herbivores that eat producers (plants) to obtain energy.
Secondary consumers: are carnivores that eat primary consumers for energy.
Tertiary consumers: are top predators that eat secondary consumers, often having no natural enemies.
*Producers convert sunlight into energy through photosynthesis, forming the base of the food web.
*Herbivores consume plants, transferring energy from producers to higher trophic levels.
*Omnivores eat both plants and animals, adding flexibility to energy flow in the food web.
*Carnivores prey on herbivores and other animals, regulating populations and transferring energy up the chain.
*Decomposers break down dead organic matter, recycling nutrients back into the ecosystem for producers.
Habitat: A habitat is a place where a living thing survives. The habitat of an organism is often described as its environmental ‘address’. All organisms have spread features that help them ti survive in their habitat. These factors help organismsto get food and water, protect themselves and build their homes.
In a food chain and food web, energy transfer occurs from one trophic level to the next.
Producers (plants) capture solar energy through photosynthesis and convert it into chemical energy.
Primary consumers (herbivores) eat the producers, acquiring about 10% of the energy stored in the plants.
Secondary consumers (carnivores) eat primary consumers, gaining a similar percentage of energy (around 10% of what the herbivores consumed).
Tertiary consumers, being top predators, receive energy by consuming secondary consumers, again at about 10%.
NATURES FURY
Structure of the Earth
There is 3 main parts of the Earth’s structure which are in order from top to bottom
Crust(about 5-70km thick with a temperature of of 15 degrees containing minerals like granite and basalt.)
Mantle(A mostly solid layer with a thickness of about 2900km, larger than the other layers with also a temperature of 500-4000 containing minerals like silicon and magnesium.)
Outer Core:(A liquid layer with a thickness of 2200km with a temperature between 4500-5500 containing liquid iron and nickel.)
Inner Core(Solid layer with a thickness of 1200km with a temperature of 5500-6500 containing solid iron and nickel.)
Tectonic Plates
Before the Earth’s land split into pieces it used to be together and was a super continent called Pangea
Alfred Wegner as the first person to formulate a complete statement of the continental drift hypothesis and called it Pangea.
A tectonic plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.
Tectonic plates move because of convection currents which are driven by the temperature between the core and mantle.
Types of tectonic plates
Oceanic Plate:is usually about 5–10 km thick and is mostly made up of basalt, a dense volcanic rock.
Continental Plate:is usually between 20–70 km thick and is less denser than oceanic crust.
Plate Boundaries
A plate boundary is the region where two tectonic plates meet. There are three main types of plate boundaries, each characterized by different geological activities:
Convergent boundary:Two neighbouring plates that are moving towards each other
Oceanic–oceanic: As shown in the interactive, when two plates with oceanic crust converge, one plate sinks beneath the other plate into the mantle. This is called subduction and it produces a deep trench on the seafloor. Magma is generated above the subducting plate, forming a chain of volcanoes.
Oceanic–continental: Subduction also occurs in this case – the much denser oceanic crust always sinks beneath the continental crust. This produces a trench along the subduction zone and volcanoes on the continental crust.
Continental–continental: Continental crust is too light to sink into the mantle. So when two continents collide at a convergent boundary, the continental crust is pushed up to form high mountain ranges.
Divergent Boundary:Two neighbouring plates that are moving apart from one another
Oceanic–oceanic: As shown in the interactive, when two plates with oceanic crust pull apart, a mid-ocean ridge forms. Cracks in the thin crust allow magma to rise up from the mantle and erupt from deep sea volcanoes. This process produces new oceanic crust and causes seafloor spreading.
Continental–continental: A divergent plate boundary in continental crust creates a long depression known as a rift valley. Rising magma pushes up the thinner crust and creates volcanoes along the rift valley. A good example of this is the East African rift valley, where the African continent is slowly splitting apart.
Transform Boundaries:When two plates slide past each other, they form a transform boundary.
The two plates slide past each other along a large crack in the crust
This is known as a fault. Faults are not perfectly straight, so the movement of the plates causes pressure to build up at sticking points.
When the pressure becomes too great, a sudden movement occurs and this triggers an earthquake. These faults do not usually allow magma to rise up through the crust, so volcanic activity is unlikely.
Ways that tectonic plates move
Convection Currents: Heat from the Earth's core creates convection currents in the mantle. Hot, less dense material rises, while cooler, denser material sinks. This movement creates a continuous cycle that drives the plates above.
Plate Movement: The tectonic plates float on the semi-fluid asthenosphere beneath them. As convection currents push and pull the mantle, they exert forces on the plates, causing them to move.
Arent Faults and Plate Boundries the same thing then?
No,Faults are cracks in the Earth's crust that occur within a tectonic plate, while plate boundaries are the boundaries between different tectonic plates.
How Do Earthquakes Happen Along Plate Boundaries and Faults?
Earthquakes occur when there is a sudden movement on the Earth’s crust. Most movement on the Earth’s crust takes place along plate boundaries. There are three main types of plate boundaries; they include converging (moving together), diverging (moving apart), and sliding or transform plate boundaries. There is a direct correlation between the plate boundary and the type of fault associated with an earthquake
Earthquakes
An earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earth's crust or volcanic action.
The Focus is the point where the energy is released from an earthquake. The energy is seismic waves that is released from the focus which travels through the crust.
The epicentere is the point directly above the focus and is usually where the most damage occurs
The Two types of seismic waves
Body Waves(Travel through the interior of the earth)
Surface Waves(Travel on the surface of the Earth)
Seismic waves are created by the release of energy in the crust, this can be from the build up and release of tension of cracks in the crust known sas faults.(The deeper the focus the weaker of the seismic waves being produced.)
The Ring of Fire
The Ring of Fire is a horseshoe-shaped zone of high seismic and volcanic activity that encircles the Pacific Ocean. It is characterized by numerous active volcanoes and frequent earthquakes due to tectonic plate interactions, primarily along convergent and transform boundaries.
Key features of the Ring of Fire include:
Volcanoes: Many of the world's active volcanoes are located here, including Mount St. Helens, Mount Fuji, and Mount Pinatubo.
Earthquakes: The area experiences frequent and often powerful earthquakes, resulting from the movement of tectonic plates.
Tectonic Activity: It is associated with subduction zones, where one tectonic plate is forced beneath another, as well as transform boundaries where plates slide past each other.
Volcanoes
Volcanoes are geological formations that occur when molten rock (magma) from beneath the Earth's crust escapes to the surface. This can happen through various processes, resulting in a range of volcanic types and eruptions.
Types of Volcanoes
Sheild Volcanoes(Broad, gently sloping sides built up by the flow of low-viscosity basaltic lava.)
Stratovolcanoes(Steep, conical mountains formed by alternating layers of lava flows, ash, and volcanic rocks.)
Cider Cone Volcanoes(Small, steep-sided volcanoes formed from the accumulation of volcanic debris and ash around a single vent.)