Explore & Learn

To know what wifi is, we need to learn about waves. All the parts of a wave A wave is a disturbance in a medium that carries energy without a net movement of particles. Sound is an example of a wave. There are two types of waves, Transverse and longitudinal. Transverse wave- A wave in which the medium vibrates at right angles to its propagation direction. A ripple in water is an example; Light is also a transverse wave. Longitudinal wave- A wave vibrating in the direction of propagation. Sound is a longitudinal wave. In a longitudinal wave, the Molecules, mostly air molecules, hit the molecules in front and create a compression and expansion state across the point from where it is created till the point it stops. Reflection and refraction of waves- Reflection- Reflection is the bouncing back of light or sound when it hits a surface. When a light, for example, reflects, there are factors like Incident ray, reflected ray, angle of reflection, and angle of incident. Refraction- Refraction is the bending of a ray when it travels from one medium to another. Optical fiber- An optical fiber, or optical fiber, is a flexible glass or plastic fiber that can transmit light from one end to the other. IN PROGRESS...

 Oscillation & Frequency in a Wave Oscillation is the repeated motion of a wave or object, like a pendulum swinging back and forth, in waves . Frequency is how many oscillations happen in one second, measured in Hertz (Hz). Higher frequency = more waves per second! •  Transverse vs. Longitudinal Waves • Transverse Waves – The vibration is perpendicular to the wave direction (e.g., light waves, water waves). • Longitudinal Waves – The vibration is parallel to the wave direction (e.g., sound waves, seismic waves).  Optical Fibre – How It Works! Optical fibres are thin glass or plastic strands that transmit light signals using total internal reflection. They are used in internet cables, medical imaging, and communication because they send data fast and without signal loss! Refractive index The refractive index (n) tells us how much light bends when entering a new material. Higher n means light slows down more and bends more (e.g., light bends when entering water from air).  Circuit Breakers & Fuses – Electrical Safety! • Fuse – A thin wire that melts if too much current flows, breaking the circuit and preventing fires. • Circuit Breaker – A switch that automatically turns off when the current is too high, then can be reset.  How Magnets Lose Their Magnetism! •  Heat – High temperatures disturb the magnetic domains. • Hammering – Shaking the structure misaligns the domains. • Strong Opposite Magnetic Field – Cancels out the original magnetism.

Impacts of Urban Growth • Urban areas offer a variety of opportunities to people and businesses • However, rapid and unplanned urbanisation creates a range of problems, including • Poor housing • Deprivation/inequality • Unemployment • Along with congestion, transport, crime, and poor environmental quality issues • The speed of development is greatest in LEDCs, e.g. Sao Paulo in Brazil, which grew from 7 million people to over 20 million in 40 years and is now the second-largest urban area in the Americas Transport • The provision of roads and public transport tends to be poor in quality, size, and reliability • Rapid development leads to transport systems becoming easily overloaded and overcrowded • Urban congestion varies over the week, time of day, the weather, and the season • High numbers of vehicles create high levels of atmospheric pollution, such as smog • As poor rural migrants arrive, there is a lack of affordable housing, and demand is high • Transportation issues mean people will have to live closer to their employment • Temporary or informal settlements arise, adding to overcrowding and poor living conditions, so adding to already cramped/congested conditions around the city Housing • Availability and affordability of housing cannot keep up with the rate at which the urban population is increasing in LEDCs • This leads to people building their own homes on any vacant land using scrap materials like cardboard, corrugated iron and plastic • They are unplanned and unregulated housing (informal settlements) with little sanitary facilities, freshwater or reliable energy supply • Usually on land not owned by them and found: • In areas of no economic value • On the urban edges or fringes • Along main roads or railways • Clinging onto the side of steep slopes • Depending on the country, these informal settlements are also called: • Favelas in Brazil • Shanty towns in the West Indies and Canada • Bustees on the Indian subcontinent • Skid row in the USA • Townships in South Africa • In LEDCs, about a quarter of urban inhabitants (1.6 billion) live in these impoverished slums and squatter settlements and by 2030, the UN estimates that 1 in 4 people on the planet will live in some form of informal settlement • Some cities have 'mega-slums'; these are very large, overcrowded areas usually within megacities • The largest are found: • Nairobi, Kenya, with a population of 1.5 million, is crowded into 3 sprawling slums of mud huts and tin shacks—Kibera being the largest of the 3 • Neza, Mexico City, Mexico, with a population of 1.1 million people  • Dharavi, Mumbai, India, with 1 million people in a warren of narrow lanes, interconnected shacks and single-room living spaces that double as factories • Orangi Town, Karachi, Pakistan, with an estimated population of 2.4 million people across 8,000 acres of concrete block homes with 8-10 people sharing two or three rooms • Khayelitsha in Cape Town, South Africa, with a population of 400,000 in iron and wooden shacks • These unregulated housing presents serious risks such as fire, flooding and landslides • These informal settlements typically suffer from: • Poor, overcrowded, small housing, built very close together using inadequate material and with uncertain electricity supplies • They have restricted access to water supplies • Little to no sanitation facilities and no solid waste disposal, which leads to a polluted and degraded local environment • There are inadequate health facilities, which, along with poor living conditions, increase sickness and death rates • The population of the squatter settlements lives in an insecure situation because landowners or other authorities might forcibly remove them Issues of the informal economy • Megacities have rapidly growing populations and job creation cannot match the pace of growth • As a result, unemployment and underemployment are not unusual  • People will often work on street corners doing informal work like shining shoes, giving haircuts, taxing, selling water or food  • These jobs are often unskilled and labour-intensive and require little money to set up  • The informal economy leaves cities without revenue to provide adequate services as workers pay no taxes • It also makes wages and working conditions difficult to regulate Deprivation and inequality • Deprivation is connected with poverty and occurs when a person’s well-being falls below an acceptable minimum standard • The minimum standard varies from country to country and applies to several different aspects of daily life • It is more than just not having enough money Cycle of poverty • All cities have levels of inequality, but LEDCs are amongst the worst affected • Many low-income families are 'pulled' to informal settlements around towns and cities looking for a sense of 'belonging' with others in the same situation • For others without a strong social network or cities with recently arrived large populations, high levels of crime, begging and petty theft are more common • Overall, this creates urban poverty that degrades both the physical and social environment around that area • This makes it difficult for people to escape from poverty and they fall victim to the vicious 'cycle of poverty,’ and urban poverty becomes ingrained within the city • Combined with a lack of suitable work, housing, water supply, sewerage, solid waste disposal and pollution, the quality of life for people in cities is low • Poverty and deprivation are passed on from one generation to the next • Children will tend to get less parental support and usually have to attend inadequate schools • They also tend to leave school early with few qualifications • Lack of qualifications means they cannot find well-paid employment and rely on social handouts • Children they have will be born into this cycle and so families remain ‘trapped’ and unable to improve their circumstances • This feeds into a lower quality of life Impacts of urban growth on rural areas • Rise of the suburbanised village • Originally, these were quiet, independent places with basic services and located near large urban areas • Also known as 'dormitory or commuter towns' and had a residential population that commuted to work • As people have moved out of the city for retirement, family or work reasons, these areas have changed • New, large, expensive housing estates with detached or semi-detached homes; some are gated communities • Urban style services increased—hence the change in name to 'suburbanised' village • The commuter belt means new roads and public transport links • New businesses such as pubs, restaurants, supermarkets and hotels have opened • Dilution of traditional country life