|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.Read More...
|6 years 1 week ago|
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.Read More...
|6 years 31 weeks ago|
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.Read More...
|6 years 31 weeks ago|
|Solar Energy: How do photovoltaics work?||
Keywords: photovoltaics, solar, solar panel
How does energy from the sun get transformed into electricity? Learn how photovoltaic panels work, converting light into electrical energy.
Learn how photovoltaic panels work, converting light into electrical energy.Read More...
|1 year 21 weeks ago|
|Light Bulb Efficiency and Hand Crank Energy Generation||
Keywords: breadboard, circuit, efficiency, electricity generation, energy, energy conversion, Lend an Experiment (LEx), lighting
What does it really take to power a light bulb?
This activity is part of the LEx (Lend an Experiment) Climate Kit. Students compare the power consumption of incandescent and LED bulbs through the use of hand crank generators and a simple circuit. Concepts include the conversion of mechanical to electrical energy, power and efficiency, and measurement estimation. There is an option to also investigate the efficiency of the hand crank generator.Read More...
|1 year 27 weeks ago|
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.Read More...
|6 years 27 weeks ago|
|Generating Electricity: Wind and Water||
Keywords: electricity, electricity generation, hydro-electricity, Lend an Experiment (LEx), wind, wind energy, wind turbines
A match made in energy heaven, wind and water are wonderful sources of clean, renewable energy. Let us see what goes into this electricity generation by making some wind and water turbines ourselves!
This activity is part of the LEx (Lend an Experiment) Climate Kit. Students generate their own wind or hydro electric power by constructing wind/water blades, exploring how mechanical energy from external sources can be harnessed and turned into electrical energy. The effect of different gear ratios can also be explored.Read More...
|1 year 16 weeks ago|
Keywords: coils, electricity, electricity generation, magnetic field, magnets
Generating electricity using just a magnet and a wire?
A useful voltage can be obtained by moving a wire perpendicularly through a magnetic field; the electrons in the wire are pushed to one side creating a flow of electricity which is perpendicular to both the magnetic field and direction of wire motion.Read More...
|6 years 32 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.Read More...
|5 years 32 weeks ago|
|Capturing Solar Energy with Photovoltaic Cells||
Keywords: Lend an Experiment (LEx), photovoltaic cell, photovoltaics, resistance, solar, solar cells, solar energy
Did you know that the amount of power from a solar panel depends on what it's connected to? Explore how photovoltaic panels work, converting light into electrical energy, and learn how you can find the maximum power output from a solar panel.
This activity is part of the LEx (Lend an Experiment) Climate Kit. Students use solar panels to generate electrical power, exploring how light energy can be turned into electricity. Students connect the photovoltaic cells to different loads to find their peak power output.Read More...
|1 year 15 weeks ago|