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"Generating electricity is not only inefficient, it also makes pedal power less sustainable, less robust and more costly. To begin with, batteries have to be manufactured, and they have to be replaced regularly. This requires energy, which can completely negate the ecological advantage of pedal power. According to this research paper (pdf), the embodied energy of a 150Wh lead-acid battery (like the one offered with the Windstream pedal power generator) is at least 37,500 Wh, which equals 250 full charges of the battery (more sources: 1/2). In other words: if you can deliver 75 watts of power to the battery, you have to pedal for 500 hours in order to generate the energy that was needed to manufacture the battery. Because the life expectancy of a lead-acid battery can be as low as 300 discharge/charge cycles (sources: 1/2), you are basically pedalling to produce the energy required to manufacture the battery. If you also factor in the embodied energy of other electronics and parts, the ecological advantage of a pedal powered generator connected to a battery becomes rather doubtful. It might costs more energy than it delivers."

"1. The teacher is choosing the technology. It's not always possible, but when you can, let the students choose, and see what happens. Not all of them will be able to. Some need help; so let other students help them. 2. The teacher is choosing the function. This doesn't mean you can't choose the function, but if you students can't control the technology the use nor its function, this can be problematic: the learning is passive from the beginning. 3. The teacher is determining the process. To an extent you have to, but don't overdo it. 4. The technology is distracting. If the technology is more magical than the project, product, collaboration, process, or content itself, try to muffle the bells and whistles. Or use them to your advantage. 5. The technology isn't necessary. You wouldn't use a ruler to teach expository writing, nor would you use a Wendell Berry essay to teach about the Water Cycle. No need for a Khan Academy account and a fully-personalized and potentially self-directed proficiency chart of mathematical concepts just to show a 3 minute video on the number line. 6. The process is too complex. Keep it simple. Fewer moving parts = greater precision. And less to go wrong. 7. Students have access to too much. What materials, models, peer groups, or related content do students actually need? See #6. 8. The teacher is the judge, jury, and executioner. Get out of the way. You're (probably) less interesting than the content, experts, and communities (if you're doing it right). 9. They artificially limiting the scale. Technology connects everything to everything. Use this to the advantage of the students! 10. They're not limiting the scale. However, giving students the keys to the universe with no framework, plan, boundaries or even vague goals is equally problematic. 11. Students access is limited to too little. The opposite of too board a scale is too little-akin to taking students to the ocean to fish but squaring of

"Burden of Poverty Lacking money or time can lead one to make poorer decisions, possibly because poverty imposes a cognitive load that saps attention and reduces effort. Mani et al. (p. 976; see the Perspective by Vohs) gathered evidence from shoppers in a New Jersey mall and from farmers in Tamil Nadu, India. They found that considering a projected financial decision, such as how to pay for a car repair, affects people's performance on unrelated spatial and reasoning tasks. Lower-income individuals performed poorly if the repairs were expensive but did fine if the cost was low, whereas higher-income individuals performed well in both conditions, as if the projected financial burden imposed no cognitive pressure. Similarly, the sugarcane farmers from Tamil Nadu performed these tasks better after harvest than before. Abstract The poor often behave in less capable ways, which can further perpetuate poverty. We hypothesize that poverty directly impedes cognitive function and present two studies that test this hypothesis. First, we experimentally induced thoughts about finances and found that this reduces cognitive performance among poor but not in well-off participants. Second, we examined the cognitive function of farmers over the planting cycle. We found that the same farmer shows diminished cognitive performance before harvest, when poor, as compared with after harvest, when rich. This cannot be explained by differences in time available, nutrition, or work effort. Nor can it be explained with stress: Although farmers do show more stress before harvest, that does not account for diminished cognitive performance. Instead, it appears that poverty itself reduces cognitive capacity. We suggest that this is because poverty-related concerns consume mental resources, leaving less for other tasks. These data provide a previously unexamined perspective and help explain a spectrum of behaviors among the poor. We discuss some implications for poverty policy."

"The transition from unicellular to multicellular life was one of a few major events in the history of life that created new opportunities for more complex biological systems to evolve. Predation is hypothesized as one selective pressure that may have driven the evolution of multicellularity. Here we show that de novo origins of simple multicellularity can evolve in response to predation. We subjected outcrossed populations of the unicellular green alga Chlamydomonas reinhardtii to selection by the filter-feeding predator Paramecium tetraurelia. Two of five experimental populations evolved multicellular structures not observed in unselected control populations within ~750 asexual generations. Considerable variation exists in the evolved multicellular life cycles, with both cell number and propagule size varying among isolates. Survival assays show that evolved multicellular traits provide effective protection against predation. These results support the hypothesis that selection imposed by predators may have played a role in some origins of multicellularity."

"Carbon dioxide (CO2) is a gas essential for life- animals exhale it, plants sequester it. It exists in Earth's atmosphere in comparably small concentrations, but is vital for sustaining life. CO2 is termed a greenhouse gas (GHG) - a gas which absorbs and emits thermal radiation creating the 'greenhouse effect'. Along with other greenhouse gases, such as nitrous oxide and methane, CO2 is important in sustaining a habitable temperature for the planet: if there were absolutely no GHGs, our planet would be simply too cold. It has been estimated that without these gases, the average surface temperature of the Earth would be about -18 degrees celcius.1 Since the Industrial Revolution, however, energy-driven consumption of fossil fuels has led to a rapid increase in emissions of CO2, disrupting the global carbon cycle and leading to a planetary warming impact. As an international community, UN member parties have set a target of limiting average warming to 2 degrees celcius above pre-Industrial temperatures."

"A kit to build a mechanical display that cycles through the numbers 0-9 by turning a crank. Do you love building mechanical contraptions? Complicated looking gear trains that perform some task? Then this kit is for you ! However, beware. It is not for the faint-hearted. The assembly instructions are 26 pages long. The counter comprises of well over 100 parts. If you want to take it even further you can install a motor and drive it automatically."

Gran blog de science

"Según Kolb, a la hora de aprender se ponen en juego cuatro capacidades diferentes: Capacidad de Experiencia Concreta (EC): ser capaz de involucrase por completo, abiertamente y sin prejuicios en experiencias nuevas. Capacidad de Observación Reflexiva (OR): ser capaz de reflexionar acerca de estas experiencias y de observarlas desde múltiples perspectivas. Capacidad de Conceptualización Abstracta (CA): ser capaz de crear nuevos conceptos y de integrar sus observaciones en teorías lógicamente sólidas. Capacidad de Experimentación Activa (EA): ser capaz de emplear estas teorías para tomar decisiones y solucionar problema David A. Kolb y Roger Fry crearon el conocido como "Círculo del aprendizaje a través de la experiencia". Los autores argumentan que el aprendizaje puede comenzar en cualquiera de los cuatro puntos, aunque los más habitual sea comenzar por una experiencia concreta. Igualmente señalan que más que un círculo, debe entenderse la progresión cognitiva como una espiral que va pasando sucesivamente por cada uno de los cuatro tipos de actividades. Como desarrollo de este modelo, los autores propusieron un cuadro de estilos cognitivos: dado que no era habitual que los distintos individuos fueran igualmente capaces en los cuatro tipos de actividad, podían distinguirse cuatro estilos según sus competencias se inclinasen más por un tipo de actividad u otro."