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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.

6 years 36 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.

5 years 5 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.

6 years 41 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?

6 years 49 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.

5 years 35 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.

6 years 40 weeks 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?

6 years 48 weeks 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.

6 years 48 weeks 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.

6 years 48 weeks 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.

6 years 48 weeks ago
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