# Hot Education Posts  ### How To: Make maganese heptoxide (permanganic acid)

This video tutorial is in the Education category which will show you how to make manganese heptoxide (permanganic acid). This procedure is extremely dangerous. Manganese heptoxide is an extremely powerful oxidizing agent. It has the ability to set fuels on fire from mere contact. Get an old dish and put a spatula full of potassium permanganate on it. Add a few drops of concentrated sulphuric acid. A green liquid is formed which is the manganese heptoxide. Now you can add any fuel like butanol... ### How To: Use superglue to reveal latent fingerprints

Do you need to check a scene for prints, or are maybe just curious about the techniques of forensic science? In this video, Robert Bruce Thompson from the Home Scientist unravels the mysterious of forensic fingerprinting using common materials that you may already have sitting around in your home right now. Explains and demonstrates the process of superglue fuming step-by-step to reveal latent fingerprints. Includes great tips on how to improve and speed up the process using household products. ### How To: Find a data point (Xi) with the Z-Score formula

In this free video math tutorial, we learn how to use the Z-Score formula to find a data point (Xi) in statistics. With mathematics, as with anything else, not everyone progresses at the same rate. Stats is no exception. Happily, in the age of Internet video tutorials, this isn't a problem. Those who progress quickly can go beyond what's being taught them and those who are struggling likewise have all the time in the world to catch up. Whether you need help finishing your homework or studying... ### How To: Find the 100th term in a sequence

Need to find the nth term in a given arithmetic sequence? See how it's done with this free video math lesson. Need help finding the From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's seri... ### How To: Use vertex formula to find the vertex of a parabola

Looking for a guide on how to find the vertex of a parabola using the vertex formula? Learn how with this free video algebra lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). ### How To: Find the area and volume of prisms

This helpful video gives simple step by step instructions on how to find area and volume of prisms. To find the area of a prism you must first find the area of the base, it may be rectangular, triangular, or otherwise. You must then multiply the area of the base times the height. Examples of all types of scenarios are given to better explain the method of finding the area. To find the volume of a triangular prism you must first find the area of the base. The next step is multiplying the area ... ### How To: Make chlorine gas with pool chlorine and hydrochloric acid

Chlorine gas is a very useful oxidant, which was first introduced as a toxic weapon by the German Army. Even today, it's still used as a weapon, most recently in the Iraq War by insurgents. But chlorine gas has more useful (and less lethal) applications, and if you want to learn how to make some at home, NurdRage has the answers. ### How To: Empty a large water bottle in two seconds with a straw

Bottled-beer chuggers the world over already know that letting air into your beverage with a straw makes it pour faster into your mouth. Did you know, however, that the same technique can be modified and used to empty a fluid into another container (or onto the floor) even more quickly? This video will show you how to use a modified straw technique to introduce air into a large bottle of water or other drink bottle, causing the contents to empty at a torrid pace. ### How To: Find the area of a circle when you know the diameter

In this video, it is shown how to calculate the area of a circle where the diameter is given. The formula for calculating the area of a circle is pi multiplied by square of radius. Radius is actually half of the diameter. In this video, the diameter is given as 10.6 meters. Hence, the radius will be half of 10.6 which is equal to 5.3 meters. Now, to find the area we shall multiply pi with the square of 5.3. Square of 5.3 is 28.09. If we multiply 28.09 with pi we shall get the area of the circ... ### How To: Find the equation for a growth pattern

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find an equation that describse the growth pattern of a sequence of blocks. ### How To: Calculate the height and volume of a pyramid

Need to know how to calculate the height and volume of a pyramid in geometry? Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). ### How To: Find the equation of a circle given: center & tangent

In this video, the instructor shows how to find the equation of a circle given its center point and a tangent line to it. To do this, take a graph and plot the given point and the tangent on that graph. Now, from the center of the circle, measure the perpendicular distance to the tangent line. This gives us the radius of the circle. Using the center point and the radius, you can find the equation of the circle using the general circle formula (x-h)*(x-h) + (y-k)*(y-k) = r*r, where (h,k) is th... ### How To: Determine the empirical and molecular formulas for a compound in chemistry

In this free video science lesson from Internet pedagogical superstar Salman Khan, you'll learn how to determine the empircal and molecular formulas of a substance given percent composition. Whether you need help studying for that next big test or could just use a hand finishing your homework, you're sure to be well served by this video lesson. For more information, including detailed, step-by-step instructions, take a look. ### How To: Solve a 2x2 system of linear equations with inverses

See how to solve a two-by-two system of linear equations using inverses (derived from determinants). Learn how with this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). ### How To: Prove Rank(A) = Rank(transpose of A) in linear algebra

Learn how to prove that the rank of a matrix, A, is equal to the rank of its transpose in linear algebra. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). ### How To: Find the slope from a set of points

To find the slope of a line you must have two points and then you must plug in the two points into the slope formula. The slope formula is m= y2-y1 over x2-x1. If the slope is a fraction be sure to reduce to the lowest. Remember if a number is divided into zero it is zero, if zero is divided into the number it is undefined. A calculator can help one remember this. Horizontal lines have slopes and vertical lines do not. Drawing the lines on a graph can help you see the actual slopes and which ... ### How To: Find the x & y intercepts of rational functions

In this tutorial the instructor shows how to find the x and y intercepts of rational functions. Finding the intercepts of a rational function is similar to finding the intercepts of other normal equations. You can find the x intercept of the equation by setting the value of y to zero and solving the equation. Similarly you can solve the y intercept by setting the value of x to zero and solving the equation. Now while solving this rational function for intercepts if you face a situation where ... This video explains how to calculate percentages in your head. To calculate a percentage in your head, start by breaking the percentage off into smaller units. For example 25% is 10 + 10 + 5. 30% is 10, 10, and 10. Now you have numbers you can easily work with in your head. Find 10% of the number. This is easily done by one of two methods. You can either move the decimal point one place to the left or you can drop the last number. Dropping the last number sometimes gives you an estimate, thou... ### How To: Remember "greater than" & "less than" symbols

This video shows you how to easily remember "greater than" and "less than" math symbols. The first thing you have to remember is that "less than" symbol looks like the letter L ("less than" symbol is "<"). When you see this sign, remember that < looks like L and means "less than". The other symbol, "greater than" does not look like the letter L, therefore it cannot be "less than" and it's easier to remember. The "greater than" symbol is ">". That's it! Good Luck! ### How To: Divide decimals

Here we are, learning how to divide decimals. So we are dividing a whole number or a fraction by a fraction. How this presenter does this is by moving the decimal two places to the right on both the top and bottom of the sum. In other words, he multiplies the two numbers by 100. So 2 becomes 200 and .25 becomes 25. So much easier to divide 200 by 25 than to divide 2 by .25. Provided you've multiplied both the top and bottom by the same amount, the result will be the same, because the relative... ### How To: Build a wave machine out of household items

In this tutorial, we learn how to build a wave machine out of household items. You will need: 20 straws, 40 paper clips, 2 pieces of tape, and 1 washer to make this. First, you will need to pull out a long string of tape and lay it down with the sticky side up. After this, you will need to stick the straws on top of the tape in a row all going next to each other. Do this from the top to the bottom until all of the straws are stuck on. Then, stick the washer to the top and you are finished wit... ### How To: Make your own nylon

In this tutorial, we learn how to make your own nylon. You will need: pipettes, pipette filler, forceps, beaker, stir rod, sebacoyl chloride and hexanediame solution. Now, pour some of the hexanediame solution into the small beaker. Add in a food coloring if you want to make this a specific color. After this, add in 4 cc's of sebacoyl chloride and carefully drip into the side of the beaker. You should see a layer of where the two liquids are after this. Now, take your tweezers and reach into ... ### How To: Solve word problems involving domain and range

See how to find the domain and range of a function implied by a word problem with this free video math lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutor... ### How To: Factor trinomials using the Berry factoring method

In this free video math lesson YAY MATH, we learn how to factor trionmials using the Berry method. With mathematics, as with anything else, not everyone progresses at the same rate. Algebra is no exception. Happily, in the age of Internet video tutorials, this isn't a problem. Those who progress quickly can go beyond what's being taught them and those who are struggling likewise have all the time in the world to catch up. Whether you need help finishing your homework or studying for that next... ### How To: Calculate the width of a fence given its length and perimeter

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find the width of a fence when given numbers for its length and perimeter. ### How To: Determine the eigenvalues of a 3x3 matrix

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to determine the eigenvalues of 3x3 matrices in eigenvalues. ### How To: Turn pennies into silver and gold coins with zinc

One of the most famous and repeated chemistry experiments involves money. Some would say this is more of a trick than an experiment, but you can be the judge of that. No one can just turn pennies into silver or gold coins, but someone with a few chemicals can. So, if you want to cooler cents in your pocket, try out this chemistry trick yourself. Nurd Rage (Dr. Lithium) shows you how to turn pennies into silver and gold coins using zinc. ### How To: Find least common multiple in rational expressions

This series walks you through the steps of finding the least common multiple in rational expressions. This excellent video shows you a clean board, with the instructors voice showing exactly what to do. Don't fret, any question you may have, will be answered. Watching this video will make you feel like your back in the classroom but rather comfortably from your home. ### How To: Find the perimeter & area of a rectangle

This video starts out with a basic view of a rectangle and its dimensions. The base is 7 inches while the sides are 4 inches. It then displays the formula for finding the perimeter of the rectangle which is the addition of both bases and both sides. After the substitution of the values into the formula you can quickly come up with the perimeter. Then moving on the area, the formula is the base multiplied by the side. In this case, the base being 7 inches and the side being 4 inches you come o... ### How To: Find y-intercept with an equation in point slope form

In this tutorial the instructor shows how to find the Y-Intercept given the equation of the line in Point-Slope form. He shows how to do this with an example. He tells to substitute the value of x to zero to find out Y-Intercept as Y-Intercept is nothing but the point where the line meets x-axis, where the value of x co-ordinate is zero. By watching this simple tutorial you can easily compute the Y-intercept of an equation in point slope form.