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Transmitting Electricity

Keywords: power, resistance, resistivity, transformer, voltage

If high voltage is so dangerous, why do we transmit electricity that way?

Transmitting power at higher voltages ensures that power can be transmitted over long distances with minimal losses; if transferred at a low voltage, the transmission distance has to be greatly minimized, which is impractical.

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7 years 47 weeks ago

Transformers

Keywords: transformer, voltage

Electrical energy is transmitted at high voltage. Which element creates the 120 V that is available in our wall plugs ant home?

Transformers operate on principles of electromagnetism to step up and step down voltages. This allows for efficient transmission of power across the grid to homes and buildings. It also ensures that the voltage from our sockets is appropriate for home and appliance use.

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7 years 46 weeks ago

Heating Efficiency

Keywords: efficiency, electric, energy, gas, power

Which is better: gas or electric heat?

Calculating or measuring efficiency means tracking the power all the way from source to end-user.

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7 years 42 weeks ago

Energy Efficiency and the Jevons Paradox

Keywords: consumption, efficiency, energy, jevons, solid state lighting

Will increasing efficiency really reduce energy consumption?

Increases in energy efficiency have been shown to increase, rather than decrease, consumption.

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7 years 35 weeks ago

What is a millisievert?

Keywords: dose, human health, ionizing radiation

One Sievert means exposure to enough high-energy electromagnetic radiation to deposit one joule of energy in one kilogram of living tissue. A millisievert is 1/1000 of a sievert. But how dangerous is it?

The measure of ionizing radiation dose, as is applicable to human health, is the Sievert (Sv). One Sv implies a health impact equivalent to one joule of X-rays being absorbed by each kg of living tissue. Activity, the mean number of decay events per second, is measured in Becquerels (Bq). Knowledge of the activity, mean energy release per event, and exposure time, allows to estimate the dose.

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7 years 16 weeks ago

Why can't you just turn a nuclear reactor off?

Keywords: nuclear reactor, shutdown

When a nuclear reactor gets into trouble, what's wrong with hitting the off switch?

When a uranium nucleus fissions into two, the resulting nuclei are not stable; they continue to decay and generate heat long after the fission chain reaction has stopped.

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7 years 15 weeks ago

Radioactive Milk

Keywords: activity, dose, nucleosynthesis, Radioactivity

Milk contains enough radioactive potassium-40 to set a Geiger Counter humming. But it didn't come from Fukushima, or any human activity.

Milk (and own bones) contains a lot of ancient radioactive potassium-40, which was made in a supernova explosion about five billion years ago.

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7 years 14 weeks ago

Oil Sands (a.k.a. Tar Sands)

Keywords: fluid-particle physics, Oilsands, Stokes' Law

How do you separate bitumen from sand with the least energy cost?

Separating bitumen from sand involves the clever use of simple fluid physics.

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7 years 5 weeks ago

Energy and Power

Keywords: definition, energy, types, useage

What is energy? Why is it such a useful concept? How does it relate to power?

Energy is the capacity to do work (both are measured in Joules). Power is the rate at which energy is transformed from one state to another, often from a stored state into work (a Joule of energy transformed per second is a Watt of power). Subsistence living requires about 200 W per person. Western living requires about 10 kW per person. Humankind currently uses about 12.5 TW of power, most from fossil fuels. Ten billion people living a western lifestyle (the not-impossible goal of many futurists) would require 100 TW of power.

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6 years 47 weeks ago

TriColour LED Flashlight

Keywords: activity, battery, breadboard, circuit, colour addition, LED, resistors, switch, tricolour LED

Make your own TriColour LED Flashlight!

This is a straightforward classroom or summer camp activity to teach students simple circuitry and the addition of colours. The students can go home with a useful and energy-efficient flashlight.

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6 years 47 weeks ago
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