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Hydrogen peroxide is a chemical compound with the formula H2 O2. It is a colourless liquid, slightly more syrupy than water.

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Evolution is a theory, an idea with lots of evidence. It explains why animals and plants are so good at surviving in their environments, the places where they live. What it means is that a species changes over time and can even split in two new species.

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Clownfish, moray eels, gobies and other fish species are known to change sex, including reproductive functions. A school of clownfish is always built into a hierarchy with a female fish at the top. When she dies, the most dominant male changes sex and takes her place.

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Titration is the slow addition of one solution of a known concentration to a known volume of another solution of unknown concentration until the reaction reaches neutralization, which is often indicated by a color change.

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What happens when you add  Phenolphthalein indicator to Sodium Hydroxide (NaOH)?

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What happens when you add  Phenolphthalein indicator to Sodium Hydroxide (NaOH)?

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Is when an acid and a base react and salt and water are formed.

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Light travels at a considerably higher speed than sound. Light travels at a constant speed of 186,000 miles per second, but the speed of sound is only 761.2 mph.

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Black holes are formed when giant stars explode at the end of their lifecycle. This explosion is called a supernova. If the star has enough mass, it will collapse on itself down to a very small size. Due to its small size and enormous mass, the gravity will be so strong it will absorb light and become a black hole.

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Heavier, negatively charged particles sink to the bottom of the cloud. When the positive and negative charges grow large enough, a giant spark - lightning - occurs between the two charges within the cloud. This is like a static electricity sparks you see, but much bigger.

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How The Northern Lights Are Created VIDEO

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Blood is always red. Veins look blue because light penetrates the skin to illuminate them, blue and red light (being of different wavelengths) penetrate with different degrees of success.

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Inside an “aerial shell” firework that gets launched into the sky, there's a “bursting charge,” black powder (aka gunpowder) or a black powder substitute and a bunch of small pellets called “pyrotechnic stars.”

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Since oil is a lipid, it doesn't freeze in the typical way freezing usually occurs, according to scientists at the University of Illinois. Liids do not freeze, but the molecular movement slows down at colder temperatures.

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Why does glue not stick inside the bottle?

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Why does glue not stick inside the bottle?

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This process is called mechanical adhesion. When white glue is inside a bottle, there's not enough air inside the bottle to cause the water to evaporate to make the glue sticky. Basically, the bottle protects the glue from the air and keeps the glue runny.

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Snow is formed when temperatures are low and there is moisture - in the athmosphere and forms tiny ice crystals. When these tiny ice crystals collide they stick together in clouds to become snowflakes. If enough ice crystals stick together, they'll become heavy enough to fall to the ground.

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Yellow mucus is caused by white blood cells. When your immune system is fighting a cold virus, one of the first symptoms is clear, runny mucus from the nose. As the cold develops, mucus usually becomes thicker and yellow, then green.

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A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.

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The Space Shuttle Columbia disaster occurred on February 1, 2003, when Columbia fell apart over Texas and Louisiana as it re-entered Earth's atmosphere, killing all seven crew members

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MapMyRun is an application you can download on you're smartphone which enables you to use the built-in GPS of your mobile device to track all of your fitness activities.

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Déjà vu is a feeling of having already experienced the present situation.

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Why does a catalyst speed up a chemical reaction?

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Why does a catalyst speed up a chemical reaction?

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A catalyst speeds up a reaction by increasing the number of successful particle collisions between reactive substances. In a typical reaction, the majority of particles do not have enough energy to react, and thus they simply bounce off each other.

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The strengths and weaknesses of acids and bases - George Zaidan and Charles Morton

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Acceleration is the change in the velocity, divided by the time. It has a value and a direction. The direction of the acceleration doesn't have to be the same as the direction of the velocity. The units for acceleration are meters per second squared (m/s2).

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Chemical equations use chemical formulas and other symbols instead of words to summarize a reaction.

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Usually when balancing an equation, you count the atoms of each element in the reactants and the products. Use coefficients; place them in front of the compounds as needed.

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- Balancing chemical equations is one of those concepts in chemistry that often confuses people. But I think we'll see that if we work through this carefully and methodically, and we also appreciate the art of balancing chemical equations, that it's actually not too bad. So first of all, what is a chemical equation? Well this is a chemical equation right over here. It's describing a reaction. So if I take an atom of aluminum and I add it to a dioxygen molecule, so a molecule that has two oxygens with it, under the appropriate conditions they will react to form aluminum oxide. And the aluminum oxide molecule has two aluminum atoms and three oxygen atoms. And so you might say, "Okay, well what's "the balancing business all about? "I have a chemical reaction. "What do I have to balance?" Well if you look carefully, you might notice that you don't have the same number of each atom on both sides. For example, right over here on the left-hand side, how many aluminums do we have? Well on the left-hand side, we have one aluminum. How many do we have on the right-hand side? Well on the right-hand side, we have two aluminums. And so aluminum just can't appear out of thin air by virtue of some magical reaction. You have to have the same amount of aluminums on both sides, and the same thing is true for the oxygens. Over here on the left-hand side, we have two oxygens. They form one dioxygen molecule that has two oxygen atoms. And then over here in the aluminum oxide molecule, we have three. We have three oxygen atoms. So once again, we can't just have miraculously an oxygen atom appear out of nowhere. So we have to balance the number of aluminums on both sides, this number and this number should be the same, and we have to balance the number of oxygens, this number and that number should be the same. So how do we do that? Well one thing might be to say, "Okay, if I've got "two aluminums here and I have one aluminum here, "well why don't I just double the number "of aluminums right over here?" I could just write a two in front of it, so now this has two aluminums, so I no longer have one aluminum here. I now have two aluminums, and so it looks like the aluminums are balanced, and they are indeed balanced. But still we have an issue with the oxygens. Over here I have two oxygens. Over here I have three oxygens. So one thing that you might say is, "Okay, well how do I go from two to three? "I could multiply by 1.5." So I could multiply by 1.5, and if I multiply 1.5 times two, that's going to be three. So now I have three oxygen atoms on this side and three oxygen atoms on this side. But the convention is that we don't like writing "1.5 molecules." We don't like having this notion of a half molecule, which is kind of this bizarre notion. We want whole number molecules. So what can we do? Well, you can imagine that this makes it very similar to what you did in algebra, an algebraic equation. We just can multiply both sides by the same number that gets rid of having this fraction or this decimal here. So if we multiplied both sides by two, we're going to do that. This is going to be a four, this is going to be a three, this is going to be a two right over here. So let me do that. Let me multiply both sides by two. So instead of two aluminum atoms, let me have four aluminum... Actually, let me just write the chemical equation first in the form that it was before. So I had aluminum plus dioxygen, a molecule of two oxygens, yielding in the reaction -- these are the reactants, this is the product -- aluminum, aluminum, aluminum oxide. So what I'm saying here is to get rid of this 1.5, to turn it into a whole number, let's multiply all of these, all of the number of molecules by two. And here, there's implicitly a one... Let me do this in a different color. There is implicitly a one right over here. So let's multiply all of these by two. So two times two is... Let me do that same color. Two times two is four... That's not the same color. Two times two is four. 1.5 times two is three. And then one times two, one times two is two. And now you can verify how many aluminums do we have on each side? Well I have four aluminum atoms on the left-hand side, and how many do I have on the right-hand side? I have four aluminum atoms. How many oxygens do I have on the left-hand side? I have three molecules of dioxygen. Each molecule has two oxygen atoms, so I have six oxygens on the left, and I have two times three oxygens on the right, or I have six oxygens. So my chemical equation is now balanced.

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Balancing chemical equations (how to walkthrough) (video) | Khan Academy

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Balancing chemical equations is one of those concepts in chemistry that often confuses people. But I think we'll see that if we work through this carefully and methodically, and we also appreciate the art of balancing chemical equations, that it's actually not too bad. So first of all, what is a chemical equation?

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Mach is the ratio of the speed of a body to the speed of sound in the surrounding medium.