TedEd Science animations and videos Photosynthesis is an ..

Around when Harland first proposed a global ice age, a climate model developed by Russian climatologist concluded that if a Snowball Earth really happened, the runaway positive feedbacks would ensure that the planet would never thaw and become a permanent block of ice. For the next generation, that climate model made a Snowball Earth scenario seem impossible. In 1992, a professor, , that coined the term Snowball Earth. Kirschvink sketched a scenario in which the supercontinent near the equator reflected sunlight, as compared to tropical oceans that absorb it. Once the global temperature decline due to reflected sunlight began to grow polar ice, the ice would reflect even more sunlight and Earth’s surface would become even cooler. This could produce a runaway effect in which the ice sheets grew into the tropics and buried the supercontinent in ice. Kirschvink also proposed that the situation could become unstable. As the sea ice crept toward the equator, it would kill off all photosynthetic life and a buried supercontinent would no longer engage in . Those were two key ways that carbon was removed from the atmosphere in the day's , especially before the rise of land plants. Volcanism would have been the main way that carbon dioxide was introduced to the atmosphere (animal respiration also releases carbon dioxide, but this was before the eon of animals), and with two key dynamics for removing it suppressed by the ice, carbon dioxide would have increased in the atmosphere. The resultant greenhouse effect would have eventually melted the ice and runaway effects would have quickly turned Earth from an icehouse into a greenhouse. Kirschvink proposed the idea that Earth could vacillate between states.

What Is Photosynthesis? From Light Energy to Chemical Energy

The following video clip is an explanation of the importance of photosynthesis.

Photosynthesis: Trapping the Sun’s Energy - …

What is fire? That may seem too-elementary a question, but understanding what it is and where it came from is vitally important for understanding the human journey. The first fires were the quick release of stored sunlight energy that life forms, plants in that instance, had used to build themselves as they made their “decisions,” and it was from vegetation that recently died and was dry enough to burn. The energy was released from burning so fast that it became far hotter (because the molecules were violently "pushed" by the reaction that also released photons) than the biological process of making animals warm-blooded. Hot enough in fact that the released photons' (energetic enough) so that human eyes could see them, in a phenomenon called flames. Flames are visible side-effects of that intense energy release. The rapid movement of the molecules as they rocketed due to that great release of energy is the motion that powers the industrial age. Those rocketing molecules move pistons in automobile engines and , and are behind the damaging explosions of bombs and the propulsive explosions of rockets. For more than one million years, all human fires were made by burning vegetation, and wood in particular. What was fire doing? Energy stored by plants, trees in particular, was violently released by controlled fires for human-serving purposes of warmth, light, food preparation (to obtain more energy from food) and protection from predation, and it also became the heart of social gatherings. Humans have stared into fires for a million years or more.

Photosynthesis: Trapping the Sun’s Energy

When humans began to raze forests and use the resultant soils to raise crops, they were working their way down through the food chain, no longer harvesting ecosystem detritus but destroying entire ecosystems literally at their roots for short-term human benefit. That practice eventually turned forest ecosystems into deserts. As this essay will survey, that was a rampant problem in all early civilizations. Eventually, humans learned to reach even further back into the ecological horizon as they began burning energy stores that were hundreds of millions of years old; was first and second. They were burned a million times as fast as they were created. In all instances, humans were releasing sunlight energy that had been captured and stored by organisms. In the 20th century, when humans began using nuclear fission, they were going even further back in time and harvesting energy stored via billions of years ago. With each new energy source, humans were harvesting older, more concentrated energy sources, which released far more energy than the previously used source. In each instance, humans plundered the energy source to exhaustion. Humans have not lived in “harmony” with nature since they learned to control fire.

Identify the part of the plant that captures sunlight to be converted to energy via photosynthesis.
Lesotho has 310 days of sunshine a year – another reason to take advantage of this form of energy.

Interactive Java Tutorials Photosynthesis

The Moon in relation to the Sun and made Earth's seasons vary within a relatively narrow range. Without the Moon, Earth could have up to 90o changes in its axis of rotation instead of the 22o-to-24.5o variation of the past several million years. If that had happened, although life may have survived, Earth’s climate would have been extremely chaotic, with part of the planet going into perpetual day while another went into perpetual night, and other wild variations. Earth would have had mass-extinction effects on those portions, and the rest of the biosphere would have been extremely challenged to survive. Complex life on Earth would little resemble today’s (if it had appeared and survived at all), if Earth’s axis tilted chaotically and severely. The primary effect of Earth’s stable tilt is the planet’s entire surface receiving relatively uniform and predictable energy levels.

This slogan stands behind the concept "sunhouse", a predominantly solar heated low-energy house.

Photosynthesis McGraw-Hill Animations.

In leafy plants, the process of photosynthesis occurs largely in the leaves. Because of this, all the necessary ingredients need to be present in the leaves for the reaction to take place. Carbon dioxide is absorbed into the leaves from the air, water is routed from the roots to the leaves, and sunlight is absorbed into the leaves through chlorophyll. Chlorophyll is a green pigment inside plant cells called chloroplasts - which also have several other structures within them. Chloroplasts are important because they are where photosynthesis takes place.

SHW systems generally do not track the sun, which is why SharperSun works more efficiently.

Explore Monika Kotze's board "Teaching: Photosynthesis ..

The derision was loud from Wrangham’s colleagues…until evidence of was found at in South Africa by using new tools and techniques. The chortling is subsiding somewhat and scientists are now looking for the faint evidence, and long-disputed evidence of 1.5-1.7 mya controlled fires is being reconsidered, although his hypothesis is still widely considered as being only "mildly compelling" at best. New tools may push back the control of fire to a time that matches Wrangham’s audacious hypothesis. Wrangham cited the Expensive-Tissue Hypothesis as partially supporting the Cooking Hypothesis, but , the energy to power the human brain may not have solely derived from cooked food’s energy benefits. Wrangham has cited numerous lines of evidence, one of which is a that has to find honeybee hives and smoke them out; the humans get the honey and the honeyguide gets the larvae and wax. According to recent molecular evidence, the evolutionary split of the honeyguide from its ancestors happened up to three mya, which supports the early-control-of-fire hypothesis. There is great controversy regarding these subjects, from recent findings that to scientists making arguments that to the social impacts of campfires. This section of this essay will probably be one of the first to be revised in future versions, as new evidence is adduced and new hypotheses are proposed.