Hydroelectricity has long been a major electricity producer for New Zealand. New Zealand’s first hydroelectric power plant was built in Otago in 1886. Hydroelectric power stations made 57% of New Zealand’s generated electricity last year. New Zealand is a great place for hydroelectric power stations, due to us being surrounded by seas, rivers and lakes.
The most conventional method of hydropower is dams. Water is held back by a huge dam. The amount of power extracted from the water depends on the river height, and water volume. Water churns through a large pipe, leading to the turbine. At the turbine, kinetic energy from the water changes into electrical energy, going off to your homes. After water has rushed through the turbine, it continues its journey to sea.
Since New Zealand has so many lakes and rivers, Hydroelectricity power plants are able to be installed all around the country.
Hydroelectricity is a very reliable power source. While solar power is only available during the day — hoping the day is sunny — and Wind power is available only when it is windy, the rivers will never cease flowing. Hydroelectricity is being produced around the clock, compared to other power sources. While Solar Power takes approximately 6 years to pay off itself, hydroelectricity is so reliable and creates so much power it can pay itself off within 2 years if placed well.
Coal and oil power plants are non-renewable. This means that their fuel source will run out. New Zealand is migrating its primary electricity sources to renewable methods, such as Hydro, and Wind. These are much better since water is almost never going to disappear – The water we drink is recycled from the dinosaurs’ time. Wind is never going to disappear either, since pressure is always changing.
The New Zealand government has made a great choice in forcing landlords to insulate their houses. It is essential in having a warm and healthy home. Older houses that lack insulation get cold in winter and too hot in summer and lost a lot of money to heating/cooling costs.
While insulation comes in many shapes, forms and sizes, they all are there to do the same job – Slowing down heat transfer. Whether this is keeping a house cooler in summer, or warm in winter, insulation is a must.
The most common insulation method is fiberglass wool, commonly known as Pink Batts. It slows down heat transfer by keeping some air trapped in the middle. The trapped air doesn’t move, effectively creating a barrier. The atoms inside fiberglass wool are far away from each other, slowing down heat transfer.
Another common method of insulating a house is Double Glazing. Single glazed windows let warm air out easily. If you install double glazing, where air is stuck between two panes of glass, much less heat is lost. This is because air is a bad conductor of heat. It slows down heat transfer via conduction majorly, as well as convection, since the pane of air in the middle is too small to circulate.
Lots of heat is often lost around the edges of doors and windows. Draught excluders are sand-filled tubes placed at the bottom of the door and windows to prevent heat loss via convection.
Since in the Southern Hemisphere western sides of houses are exposed to the most sun, we need to reduce heat transfer. We do this by tinting windows. Low-emissivity film is a thin transparent metal coating. It is stuck to windows to reduce heat transfer. Usually windows allow heat to radiate quickly, however tinting windows causes radiation to bounce back from where it came from, whether heat from the inside, or heat from the outside.
The North and Eastern sides of a house in the Southern Hemisphere often get the most sun. To reduce heat transfer, we shade the windows with eaves. Tinting will also help with the late afternoon summer sun. When the sun is the hottest, around noon, eaves will prevent a lot of sunlight radiating through the windows.
While Sound Energy requires a medium to travel through, Light does not require matter to travel – This explains why we can see in space, but not hear. Light can travel at over 299 km per second – Almost instantaneous! Light only travels in straight lines, and changes speed when travelling through different mediums. This causes us to see it as broken. When light hits something, it is reflected, and goes into your eye. The lens inside your eye focuses the light to a single point, which is then sent to your brain.
Mirrors are extremely smooth. Almost all of the light rays hitting the mirror bounce back into your eyes. If it was a rough surface, most of the light rays would scatter, instead of reflecting into your eyes. If the mirror absorbed the light, we wouldn’t be able to see anything. This is why mirrors are made with a backing of silver, followed by glass, then a clear layer of protective metal.
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