Did dinosaurs and humans coexist?

No. They narrowly missed each other on the evolutionary timescale. In this case, narrowly means about 65,000,000 years. Contrary to some creationist theories you may have uncovered if you searched for this exact term in any search engine, there is a preponderance of evidence against their claims. Read more…

Physics Equations and Formula Sheets

The following physics equations and formula sheets are some of the more useful ones I’ve come across in my recent years as a physicist. Some of these are intended to be used as-is, but you can always pull various equations and formulas from the specific topics you need and create your own.

AP Physics Exam Table of Information and Equations. 8 pages, 285k PDF. This is the sheet provided by The College Board to students when taking the AP Physics Exam. This is one of the more detailed formula sheets available. Current version copyright 2007.

MCAT Physics Equation Sheet

Who discovered the mitochondria?

The mitochondrian was first identified at the end of the 19th century by a German pathologist and histologist (tissue researcher) named Richard Altmann. It was given the name “mitochondria” by Karl Benda, a German physician. (1857-1933). [source: Read more…

How do chlorofluorocarbons (CFCs) affect the ozone layer?

CFCs are hydrocarbons in which some or all of the hydrogen atoms have been replaced by fluorine atoms. They are often used as refrigerants, solvents and until recently as propellants in aerosol cans. When released, they rise high into the Earth’s atmosphere where they interact with the Sun’s ultraviolet rays. Read more…

What is the most abundant element on Earth?

Oxygen is the most abundant. It comprises 49.5% of the total mass of the Earth’s crust, water, and atmosphere. The second most abundant is Silicon (Si) at 27.7% of Earth’s mass. Read more…

What is the most poisonous snake in the world?

While this question is often debated, the land snake commonly believed to have the most lethal poison in the world is the inland taipan. They primarily live in the arid deserts of central eastern Australia. Anything or anyone unlucky enough to be bitten by a taipan is injected with some nasty venom

Inland taipans are also called fierce snakes and can grow up to 10 feet (2.7 meters) although half of that is the norm. This snake changes color according to season. They range from dark brown to straw colored during the year but at winter they go darker and in the summer they go lighter.

Taipans hunt mammals so their poison can knock out warm-blooded, fuzzy rodents and animals, including humans. In a single strike (one bite) the venom can quickly paralyze a small animal or wipe out several adult humans. As the poison spreads, the victim will encounter headaches, nausea, vomiting and stomach pains. Sometimes there are convulsions and in extreme cases, coma.

If that’s not bad enough, the poison eats away at muscle tissue. Urine from the victim turns reddish-brown as their muscles deteriorate and pass through the kidneys. Internal bleeding is a major problem from taipan bites. The poison also prevents blood from clotting so the bite continues to bleed. This can cause internal hemorrhaging, especially in the brain. All this sucks for the bite victim but it’s great for the snake who only has to wait for its prey to stop convulsing before enjoying dinner. Taipans rarely attack humans, except in self-defense, so as long as they are left alone, humans will be too.

Source: Kidzworld.com.

What is Photosynthesis?

In a nutshell, photosynthesis is the biological process in which plants capture light and use that energy to make glucose. The sun provides this energy for chlorophyll to change molecules of carbon dioxide and water into glucose. The plants take in the oxygen and release carbon dioxide. Oxygen is also released in this reaction.

The reaction is thus: 6H2O + 6CO2 –> C6H12O6 + 6O2

In non-chemical terms this says: six molecules of water plus six molecules of carbon dioxide react to produce one molecule of glucose and six molecules of oxygen.

There is a nice description of this reaction and more information about photosynthesis at Maricopa Community College here. They add, “The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll. Most of the time, the photosynthetic process uses water and releases the oxygen that we absolutely must have to stay alive.”