### How To: Solve equations with the order of operations

In mathematics, the order of operations define the priority in which complex equations are solved. The top priority is your parenthesis, then exponents, followed by multiplication and division, and finally addition and subtraction (PEMDAS). This video tutorial demonstrates the order of operation with various examples and explains the associated methodology. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autod...

### Make Slime Without Borax: 5 Easy Recipes for Gooey Homemade Ooze

One of the only things I remember from watching Nickelodeon as a kid is the epic green slime. Looking back, I don't know what was so great about it, but every kid my age thought that being drenched in slime would be the coolest thing on earth.

### How To: Write A Letter From Teachers To Parents

Parental involvement is a crucial ingredient in the success of many children. Teachers know the saying all too well that it takes more than a village to raise a child, for one - it takes parental involvement. Thus, it is important for teachers to reach out to parents in that first week of school. Teachers should write a formal letter that is welcoming and easily comprehensible to the parent and the student. This letter should be able to communicate that the teacher values the child’s educatio...

### How To: Build a DIY electromagnet for cheap

This video shows the viewer how to make an electromagnet using common items. This is done using a broken microwave, a spool, a cordless drill, a battery and a coat hanger. The microwave transformer is dismantled and the enamel insulated wire is removed. Using the cordless drill the wire is then coiled around the spool. The iron coat hanger should then be cut into small pieces and placed in the middle of the spool. It should be secured tightly. The battery was then connected to the wired coile...

### How To: Make manganese dioxide electrodes

Various electrochemical reactions requires that anodes do not degrade when used. Carbon is cheap, but degrades easily and platinum is extremely expensive. In a previous video, you learned "How to make cobalt and manganese nitrates", and you saw that titanium could be used as a cathode, but not as an anode due to an effect called passivation.

### How To: Find the Percent Given Two Numbers

Whether you're shopping for deals, need help with a little math, or any number of other occasions, it's a valuable skill to know how to quickly figure out a percentage given two numbers.

### How To: The Best Investigatory Projects in Science: 16 Fun & Easy Ideas to Kickstart Your Project

Most of us have conducted an investigatory science project without even knowing it, or at least without knowing that's what it was called. Most science experiments performed, from elementary to high school students and all the way up to professional scientists, are investigatory projects.

### How To: Find a number given Its percent

This how-to video is about how to find a number when its percent is given. This video is really helpful and effective in finding the number when the percent is given, the following steps are explained in the video to find the number when its percent is given:

### How To: Do long division without a calculator

This video shows you step by step how to do long division without the use of a calculator. The video shows viewers two different ways to solve a division problem. It first shows how to do the problem the traditional way, then it shows how to do it according to the long division process. The long division process is where you write the whole division, multiplication, and subtraction process out showing all your work. Long division is mainly used when dividing large numbers. There are three com...

### How To: Find standard deviation

In this video tutorial, viewers learn how to calculate the standard deviation of a data set. The standard deviation of a statistical population, a data set, or a probability distribution is the square root of its variance. To calculate the standard deviation, users will need to follow these steps. 1) Find the mean of the data. 2) Subtract the mean from each data point. 3) Square each of the values you got in step 2. 4) Then find the mean of the values you get from step 3. 5) Finally, square r...

### 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: Calculate the area of a parallelogram

Calculating The Area Of A Parallelogram A parallelogram is a 4-sided shape formed by two pairs of parallel lines. Opposite sides are equal in length and opposite angles are equal in measure. To find the area of a parallelogram, multiply the base by the height. The formula is:

### How To: Make Vitriol (Sulfuric Acid) Using the Oxidizing & Electrochemical Methods

If you've been following the news lately, you've probably heard of the word "vitriol" being used as a political weapon, with people like celebrity left-winger Jane Fonda blaming conservatives like Sarah Palin for "vitriolic" attacks on Democrats and the "violence-provoking rhetoric of the Tea Party" movement for the recent Arizona shooting.

### How To: Determine the age of a fossil using carbon-14

If you have a fossil, you can tell how old it is by the carbon 14 dating method. This is a formula which helps you to date a fossil by its carbon. If a fossil contains 60% of its original carbon, how old is the fossil? The half life of carbon 14 is 5600 years. That means this is how long it takes for half the nuclei to decay. After 5600 years, if we start with a gram, we end up with half a gram. This rather complex formula shows you how to solve this puzzle using accepted scientific methods.

### How To: Find the Radius of a Circle from Arc Length

The video provides two example problems for finding the radius of a circle given the arc length. Problem one finds the radius given radians, and the second problem uses degrees.

### How To: Find a slope of a straight line with: Ax + By + C = 0

In this video the instructor shows how to find the slope of an equation which is in the form Ax + By + C = 0. He says that the formula to find the slope of a line in the above form is slope m = -A/B, where A and B are the numeric constants of the variables x and y in the given equation. He goes on and further shows how to do this with a couple of examples. He shows how to reduce any equation into the general form and how to apply the slope formula then. This video shows how to find the slope ...

### How To: Find the coordinate of a point

In this video the author shows how to plot a point on the coordinate plane. He explains about the coordinate plane and shows how to read and write points to it with an example. He says that any point on the coordinate plane has an x, y- coordinate values. He says that for any point its projection on the x-axis is its x-coordinate and the points projection on y-axis is its y-coordinate. He shows how to find this out for a sample value and plots the coordinates of it. In this video the author u...

### How To: Tie off a suspension ring for rope bondage

If you're planning on doing some bondage knots, you better learn how to do it right. This video shows you how to properly tie off a titanium suspension ring for use in your bondage activities. This video is clear and straight forward, using a large piece of rope, making it easy to see exactly how it's done. Remember to be careful with your S&M knots, especially if you're suspending someone's weight.

### How To: Find the slope of a line given 2 points with fractions

In this video tutorial the instructor shows how to find the slope of a line given two points with fractional values. To do this first name your two points as point 1 with coordinates as x1, y1 and point 2 with coordinates x2, y2. Then substitute the values in the equation of the slope which is slope m = (y2 - y1) / (x2 - x1). Now all you have to do is simply the fraction after substituting the point values. Be careful about the signs while substituting in the formula. Now finally after solvin...

### How To: Find the length of a median in a trapezoid

In this tutorial video the author shows how to find the length of the median of a trapezoid. He starts to show that we first need to add the sum of the parallel sides of the trapezoid which are on the either side of the median. Now this obtained value is to be divided by two to get the length of the median. He explains that the length of the median of a trapezoid is nothing but the average of the lengths of the parallel sides of the trapezoid. If you want to learn how to find the length of th...

### How To: How Do You Balance 14 Nails on a Single Nailhead? Find Out with This DIY Gravity Puzzle

This little brain game is all about engineering a lower center of gravity. The idea has been around forever, but most people still don't know how to do it. Trying to stack nails above the balance point will raise the CG and make the structure unstable. Here's how you can lower the CG to make a very stable structure and impress your friends.

### How To: Make iodine

Learn how to make iodine with readily available materials with Phil Torrone in order to avoid being on the DEA's list.

### How To: Create potassium iodide using elemental iodine and potassium hydroxide

Try out some home brewed chemistry by crafting your own potassium iodide using elemental iodine and potassium hydroxide, or in more scientific terms:

### News: Dissecting a Human Head Through Anatomical Illustrations

Human anatomy is something every physician must undergo as a medical student. Some move on to become great doctors, some move on to become great artists, helping to better educate students and improve upon many illustrated representations of the human body since the days of medieval medicine. But thankfully, you don't have to be in the medical profession to enjoy the beautiful art of the human body created for teaching purposes.

### How To: Find the area of irregular shapes

This video explains how to find the area of irregular shapes. Draw the shape on a grid or graph paper. This will help you divide your shape into pieces. Draw dotted lines to divide the shape into squares, rectangles or triangles. For instance, if you have an "L" shape, you can divide the shape into two rectangles. Be sure your shapes do not overlap. Calculate the area of each individual shape. The graph paper will help you determine the length and width of each shape. Add the resulting areas ...

### How To: Use the Ultrospec UV-visible spectrometer in the lab

The Department of Biological Sciences at the University of Alberta brings you this video tutorial specifically relevant to your student laboratory courses, specifically microbiology. If you're a student at any school of biology, this information will be helpful for learning how to use the Ultrospec UV-visible spectrometer and HP printer in the lab.

### How To: Find percent by mass & percent composition

In chemistry you come across problems which ask you to find the percent by mass and percent composition of each element in a chemical compound. To do this the first step is to compute the molar mass. Use the periodic table to look up the mass of individual atoms and multiply it by the number of atoms to find the mass of that element. Now add up all the masses to arrive at the molar mass of the compound. Now to find the percent composition of an element divide the total mass of each element by...

### How To: Find the lowest common multiple/LCM with a factor tree

This video lesson demonstrates how to find the lowest common multiple/lowest common denominator (LCM/LCD) using factor trees. 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: Figure out the area of quadrilaterals

Quadrilaterals are four sided shapes that are closed. They are polygons. Quadrilaterals can be classified broadly in two ways. If the quadrilateral has a two pair of parallel sides then it falls in to the parallelogram category. Further now it can be broken down in to other shapes like square, rectangle, rhombus. If it has only one pair of parallel side then it falls into the trapezoid category. To compute the are of a trapezoid first you need to know the lengths of the parallel sides. Add th...

### How To: Simplify rates and ratios with simple arithmetic

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 simplify a rate or ration using simple math.

### How To: Find the area of quadrilaterals

Parallelogram is a quadrilateral in which both pairs of the opposites are parallel. To find the area of a parallelogram first draw the diagram of a parallelogram. Parallelogram can be further divided into squares and rectangles. To calculate the area of both of these kinds of parallelograms multiply the length of the parallelogram with its height. In general the area of a parallelogram in obtained by multiplying the base of a parallelogram with its altitude. In square and rectangle cases, the...

### How To: Add and subtract fractions with different denominators

Could you use a little help figuring out how to add and subtract fractions containing different denominators? Watch 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). With this free math tutorial, you'll learn how to sum and subtract f...

### How To: Make Potassium Chlorate from Ordinary Household Bleach and Salt Substitute

If you're not just a chemistry nerd, but also a firearms freak and explosives nut, then this home brew chemistry concoction is just what you need for some cheap homemade potassium chlorate. It's a mixture of potassium, chlorine and oxygen (KClO3) and is used for such things as gun primers, propellents, and explosives (when mixed with the appropriate fuel). And guess what? NurdRage is going to show you the steps for this makeshift potassium chlorate.

### How To: Use ">" (greater than) and "<" (less than) symbols

In this video the author explains how to identify the less than (<) and greater than (>) symbols and when to use them. She explains to us to relate the numbers to animals stating that the smaller numbers are smaller animals and bigger numbers are bigger animals. Now she tells us to imagine that smaller animals are eaten up by the larger animals. So she shows a smaller number comes on the left side of '<' sign and bigger number comes on the right side of '<' sign stating that the bigger number...

### How To: Make hydrochloric acid from salt

In this tutorial, we learn how to make hydrochloric acid from salt. First, you will pour some salt into a distil flask. After this, you will add in some concentrated sulfuric acid to the salt. Next, you will let these react with each other. You will start to see gasses bubble up and the excess hydrogen chloride gas come out through the top of the tube. To create a stronger reaction, you can add heat underneath the reaction. Then, test this by exposing it to ammonium chloride. If it's the righ...

### How To: Calculate Faster Than a Calculator

When you need to crunch numbers quickly — and I mean really quickly — there's a cool method you can use to multiply two numbers together in just a few seconds.

### How To: Find the Volume of Composite Figures (Also Called Composite Shapes)

Composite figures are composed of several geometric shapes and are three-dimensional shapes. The first composite shape is a combination of a rectangular prism and a pyramid. To find the volume of the entire shape you find the volume of each individual shape and add them together. The second figure consists of a cylinder and a hemisphere. Check out the video below for the full lesson.

### How To: Make potassium nitrate at home

Believe it or not, there are cheap ways to make potassium nitrate for your chemistry experiments. And the key ingredient… "sodium-free" salt.

### How To: Make a crazy foam explosion science experiment

Check out this video to see our Fantastic Foamy Fountain in action. The experiment uses Hydrogen peroxide and dry yeast. Hydrogen peroxide is similar to water but it has an extra oxygen atom. This makes it more dangerous and only adults should handle the hydrogen peroxide.

### How To: Find the area of a triangle when given 2 sides & angle

This video shows you how to easily find the area of a triangle when you know the length of 2 sides and the angle between them. The first thing you have to do is mark the sides of the triangle by a, b, c, where a is the side between A and B, b is the side between B and C and c is the side between C and A. If you know 2 of these 3 sides an you know the angle between them you can find the area of the triangle very simple: Area= (a x b x sin c)/2, where a, b are the two sides and c is the angle b...