Energy & Environment

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How big was the aerodynamic force on Felix Baumgartner at 1342 km/h? (Or on Alan Eustace at 1321 km/h?)

Keywords: aerodynamics, drag, felix baumgartner, free fall

Did you watch Felix Baumgartner jump out of a balloon gondola at an altitude of 39 km? Here's a question for your physics students, or even your physics teacher! How big was the drag force on Felix Baumgartner at his maximum speed of 1342 km/h? Pretty enormous, right? Wrong.

Knowing next to nothing about how aerodynamic drag varies as one hits the sound barrier, there is very simple way to assess the aerodynamic drag on a falling object at its maximum speed. Even at 1432 km/h. In fact the maximum aerodynamic drag occurs afterwards when the falling object is slowing down in the denser lower atmosphere. To asses how big the force was on Felix Baumgartner, we create a simple mathematical model of his fall.

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4 years 23 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.

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4 years 28 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.

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4 years 33 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.

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5 years 3 weeks ago

CO2e

Keywords: carbon dioxide, CO2e, terminology

What does the "e" mean?

A brief primer on the meaning of "CO2e"

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5 years 5 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.

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5 years 6 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.

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5 years 6 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.

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5 years 22 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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5 years 36 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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5 years 36 weeks ago
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