Energy & Environment

Title Post date
Wind Turbines Keywords: kinetic energy, power, wind energy, wind turbines

Can wind turbines actually be used to harness a substantial amount of power?

The total energy available in wind and the power that can feasibly be extracted from it will be determined using the fundamentals of kinematics. Following, the limitations of location and machinery of wind turbines that restrict the amount of power that can be harnessed will be examined, before comparing the impact of wind energy with various other common sources of energy.

9 years 2 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.

8 years 8 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.

8 years 9 weeks ago
What do I (we) do about my (our) carbon footprint? Keywords: Carbon footprint, reduction

A very frequent question asked by students after learning about climate change is "But what can I (we) do about it?". Here are some ideas, all of which have benefits in addition to reducing greenhouse gases, and so are worth considering even if you reject the idea of anthropogenic global warming completely.

Here is a set of suggestions for science students who wish to take action to reduce their own and their family's or community's carbon footprint. Most of the ideas are about education and attitude. We also list three achievable ways of reducing your annual emissions by least a tonne of carbon dioxide.

7 years 26 weeks ago
Wave Power – A Simple Analysis Keywords: power, waves

Will wave power save us?

A look at the amount of power potentially available in water waves.

8 years 52 weeks ago
Turn the Heat Off! Keywords: energy loss, heat loss, power

Do you save more energy by leaving the heat on at night or by turning it down and reheating the house the next day?

We examine the benefit of turning off the heat when you go out.

9 years 1 week ago
True, False, or Not Sure? Philosophy of Science in the 21st century Keywords: nature of science, normal science, philosophy of science, post-normal science

Whatever happened to objective reality? Why is climate change so hard to prove?

A brief overview of normal and post-normal science.

9 years 2 days ago
Trend Analysis in the Context of Global Warming Keywords: anthropogenic climate change, climate, climate change, trend analysis

There are many sources ranging from politicians to mass media that claim that the Earth is actually cooling, not warming as scientists say it is. Unusually cold periods and local changes in weather are generally the cause for these statements. Why are these claims inaccurate?

There are many claims made refuting the existence of global warming. Most of these claims come from looking at very short term data in a very localized region. Global warming, as the name implies, is an increase in the global temperature and conclusions about it cannot be reached using measurements localized in time and space. Doing so is called "cherry picking".

3 years 42 weeks ago
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.

8 years 40 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.

8 years 39 weeks ago
Thermal Radiation Keywords: black body radiation, infrared, thermal radiation

All bodies emit radiation. So why don't we all shine in the dark?

Thermal radiation is a crucial part of our macro and micro environments. Although invisible to the eye it can be measured and imaged.

8 years 49 weeks ago
Solar Powered Airplanes Keywords: airplanes, estimation, solar cells, solar energy

If we were to coat a Boeing 747 jumbo jet with solar panels, is it possible to fly it using only the energy generated by these solar panels?

This module introduces the concept of estimation, both in the sense of rounding extremely precise numbers off to remove excessive significant figures, and simplifying a complex process (the flight of a 747) to a simpler one, by evaluating the possibility of powering a 747 with solar panels.

9 years 18 hours 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.

3 years 30 weeks ago
Solar Energy in a Temperate Climate. Keywords: photovoltaic cell, solar cells, solar energy, solar radiation

Does it pay to cover your roof with solar panels in Vancouver?

We show the example calculation of expected amount of energy, which can be obtained in Vancouver from a roof covered with solar cells.

8 years 50 weeks ago
Simple Earth Climate Model Keywords: albedo, black body radiation, climate, conservation of energy, energy balance, heat transfer, Stefan-Boltzmann law, surface temperature

Which planetary characteristics contribute to producing a mean surface temperature that makes Earth habitable?

Developing a simple model of Earth's atmosphere to infer what physical processes are important in maintaining a mean global temperature of about 14.5°C. Further, the model can also be used to show how this temperature can change.

9 years 1 week ago
Renewable Energies Keywords: biofuel, electricity generation, energy, hydro-electricity, Renewable, solar energy, wind energy

Energy is always required, whether it be for the production of goods, the supplying of services, or for transportation. Can we reduce our emissions by turning to clean sources of energy? If so, why haven't we already?

A large portion of humanity's energy demands are met using fossil fuels. Switching from fossil fuel generation to cleaner sources could greatly reduce the carbon emission put out every year. There are many ways to obtain energy cleanly, each with their own advantages and challenges.

3 years 42 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.

8 years 7 weeks ago
Low-E Glass Keywords: emissivity, thermal radiation

How do you tell the difference between low-E and regular glass?

With a cheap IR thermometer, low-E glass can be easily distinguished from the normal variety.

6 years 36 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.

3 years 35 weeks ago
Investigating the Greenhouse Effect and Passive Solar Heating Keywords: greenhouse effect, Lend an Experiment (LEx), thermal absorption

We all know a car sitting outside in the sun all day can get dangerously hot inside, but why? What does this have to do with the greenhouse effect?

This activity is part of the LEx (Lend an Experiment) Climate Kit. Students explore the way materials and surfaces interact with solar radiation. We introduce the idea of the greenhouse effect, and build a small model to illustrate how it works.

3 years 31 weeks ago
Hydro-Electric Dams Keywords: dams, greenhouse gases, hydro-electricity, power

Why is this beautiful valley in north-eastern BC about to be flooded?

A look at the generation of power by a hydro-electric dam.

9 years 2 weeks ago
Hydro-Electric Dam Demo Keywords: dams, hydro-electricity, power

Energy from Water?

An estimate of the power output from a model hydro-electric dam.

8 years 50 weeks ago
How much do grade 10 students know about our energy consumption? Keywords:

Do students understand how similar we are to the machines we make?

The human body and the internal combustion engine are quite similar in that they are both heat engines requiring chemical energy to run.
By placing a question related to this notion on a national science contest, we attempted to discover what Grade 10 students think.

7 years 7 weeks ago
Home Heating Keywords: conduction, cooling, heat exchange, heat loss, heating

Where are these houses losing the most heat to the environment? The picture on the left is taken with visible light, that on the right is taken with infrared light with a wavelength of about 10 μm.

An example of how to model the heating and cooling of thermal systems, including a look at some of the issues surrounding the heating and cooling of buildings.

9 years 1 week 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.

8 years 35 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.

3 years 24 weeks ago
Generating Electricity 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.

8 years 40 weeks ago
Food, Energy and the Environment Keywords: energy balance, Food, greenhouse gases

How do we feed nine billion people without destroying our environment?

The primary function of food is to provide our bodies with energy. Most of this energy comes ultimately from oil, with a little sunlight added, and its production is an energy-inefficient process.

7 years 10 weeks ago
Flying Keywords: aircraft, birds, energy, flight, transport cost

It takes energy to fly. How much?

We examine how much energy it takes to fly from A to B, whether by bird, model glider, small plane or 747.

8 years 45 weeks ago
Fan Efficiency Keywords: efficiency, electric fan, power

How can we measure the efficiency of an electric fan?

When you're out shopping for an electric fan, it might be a good idea to look for one that not only keeps you cool, but keeps your energy consumption low, too. Using an anemometer, Kill-A-Watt meter and a little bit of math, you can figure out how efficient your fan really is.

6 years 32 weeks ago
Energy Use in Cars 6: Gasoline Cars vs. Bicycles Keywords: air resistance, bicycle, energy use in cars, fuel economy, rolling resistance, vehicle transportation

When does a car have the same fuel efficiency as a bicycle?

A comparison of the energy cost of transportation between cars and bicycles.

9 years 2 days ago
Energy Use in Cars 5: Gasoline Cars vs. Electric Cars Keywords: electric cars, energy use in cars, fuel economy, vehicle transportation

How do the greenhouse gas emissions of electric and gasoline cars compare?

A comparison of the energy cost and greenhouse gas emissions of gasoline and electric cars.


9 years 2 days ago
Energy Use in Cars 4: Regenerative Braking Systems Keywords: energy use in cars, fuel economy, regenerative braking, vehicle transportation

What single system could be added to a gasoline car to improve its city driving fuel economy by 30-40%?

A calculation of the fuel consumption due to stop-and-go driving, for the purposes of estimating potential savings from a regenerative braking system.

9 years 3 days ago
Energy Use in Cars 3: Rolling Resistance Keywords: energy use in cars, fuel economy, rolling resistance, vehicle transportation

Why does Natural Resources Canada recommend keeping your tires inflated to conserve gasoline?

A rough calculation of rolling resistance in cars explores the impact of having underinflated tires.

9 years 6 days ago
Energy Use in Cars 2: Constant Speed Cruising Keywords: air resistance, drag, efficiency, energy use in cars, fuel economy, vehicle transportation

If a body in motion tends to stay in motion, why do we need to burn gas to travel at highway speeds?

Why do we need to burn gas to keep travelling at the same speed? The basic answer is "because if we didn't, eventually the car would stop." In everyday life, there is always friction and air resistance that opposes any motion, and if you leave a moving object alone, this friction and drag will eventually cause it to stop. This lecture looks at how this drag impacts a car.

9 years 1 week ago
Energy Use in Cars 1: Stop-and-Go Driving Keywords: efficiency, energy use in cars, fuel economy, kinetic energy, vehicle transportation

When does cycling cost more in fuel than driving?

People recommend commuting by bicycle rather than by car to save energy. However sometimes when a cyclist pushes the button to make a traffic light change, it means that a bus full of people has to stop. When a cyclist makes the bus stop like this, is the extra fuel it has to burn to get back up to speed MORE than the fuel saved by choosing to commute by bicycle rather than car?

9 years 1 week 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.

8 years 28 weeks ago
Energy Cost of Transport Keywords: energy, transport

How much energy does it take to move a person or a tonne of freight from A to B?

We compare how much energy it takes to move something from A to B using a variety of means: road, rail, water, air, and if that something is a human, walking and bicycling.

8 years 45 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.

7 years 40 weeks ago
Cycling and Showering Keywords: cycling, energy use, heat capacity, showering

Are cycle commuters, who take an extra shower, doing more damage to the environment than those who commute by car?

A recent letter to the Vancouver Sun claimed that commuting by bicycle was worse for the environment than commuting by car. The reason given was that if a cycle-commuter takes an extra shower at work (because cycling makes you sweaty), that burns the energy equivalent of a litre of gasoline, which is more than a car would burn on an average commute. Fact or rubbish?

9 years 1 week ago
Cool Roofs Keywords: albedo, carbon dioxide, emission, energy, surface temperature

Can painting our roofs white offset tonnes of CO2 emissions??

In this article, we look at how we can save energy, reduce the Earth’s surface temperature and offset carbon dioxide emissions just by making our roofs and pavements a lighter colour!

8 years 40 weeks ago
Comparing Energy and Heat Units Keywords: BTU, cost, energy, greenhouse gases, oil barrel, quad, R-value, thermal conductivity, thermal resistance, unit conversion, Watts

How do I compare heat and energy values given in different units?

A look at how to compare the costs of natural gas, gasoline and electricity and how to convert between various heat units including R-values, U-values, BTU/h, W and more.

8 years 46 weeks ago
Commuting by car or cycle - which is better? Keywords: bicycle, Carbon footprint, consumption, cycling, energy, Food, spreadsheets

It's not actually that clear...

We set out to find how much of a change it would make environmentally if one cycled instead of drove to work and then further expanded our findings to include the variables of diet composition and material goods ownership.

7 years 10 weeks ago
CO2e Keywords: carbon dioxide, CO2e, terminology

What does the "e" mean?

A brief primer on the meaning of "CO2e"

7 years 9 weeks ago
Climate Models: Simulating the Earth Keywords: climate, climate change, simulating data

Climate models can give us a great deal of information about what sort of rules the climate follows and how the climate might look like in the future. A climate model is the result of a simulation run on a virtual Earth. This simulation mimics the real Earth and its climate as well as any influences the planet might have on the climate. They are used to predict the future of the climate using computers.

The prediction of future climate is done using climate models, virtual Earths with their climates simulated many years into the future. These virtual Earths live inside computers and evolve according to complex equations solved for points in time. The results that these climate models give provide us with important information to make decisions relating to climate change before we encounter the potentially catastrophic consequences.

3 years 42 weeks ago
Clean Coal Keywords: energy, Fossil fuel, greenhouse gases, power

An oxymoron?

Calculating how much coal we have to burn in a typical large power station to produce 1 GWe for a year.

8 years 50 weeks ago
Carbon Storage Keywords: carbon dioxide, carbon emissions

Are ways to perform human control of the carbon in the atmosphere? How do we do it? Is it safe?

Humanity is not without means to control the carbon dioxide in the atmosphere. There are ways it can be sucked out of the air and placed deep underground. However, this is by no means a permanent solution and is not without its risks.

3 years 42 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.

3 years 23 weeks ago
Bottle Rockets Keywords: air, bottle, force, fuel, pressure, rocket, thrust, water

Bottle Rockets - a future mode of transport?

This article explores the physics behind bottle rockets and how they work. It also discusses whether or not bottle rockets would be a viable means of transport.

8 years 41 weeks ago
Biofuel Keywords: biofuel, energy, solar radiation, transportation

Can plants be used to fuel my car?

A look at how much land is needed to plant corn so that the energy harvested is able to power a car for one year.

9 years 21 hours ago
Syndicate content

a place of mind, The University of British Columbia

C21: Physics Teaching for the 21st Century
UBC Department of Physics & Astronomy
6224 Agricultural Road
Vancouver, BC V6T 1Z1
Tel 604.822.3675
Fax 604.822.5324

Emergency Procedures | Accessibility | Contact UBC | © Copyright The University of British Columbia