# Hot Education Posts

### How To: Write a logarithm as a sum or difference of logarithms

This video shows the method to write a logarithm as a sum or difference of logarithms. The square root of the term given is taken out as half according to the rule. Then the numerator and denominator is divided into product of factors. This is broken into the difference of numerator and denominator according to the rule. Finally, the product of factors is expressed as the sum of factors. Now we see the domain of the term. As the term is a square root of the term it should be greater than zero...

### 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: Make slime without using borax

This video shows you how to make slime, or goo, without using borax which can be harsh on some people's skin. Rather than spending money on buying slime for your children in the toy store, simply mix water and cornstarch. You can even make it any color you want just by adding food coloring. Make slime without using borax.

### How To: Build and make an erupting volcano model at home

Hmm... wondering what to do with a lazy Sunday afternoon? Why not build a volcano that can erupt? Have fun and make a mess, all in the name of science!

### How To: Turn water into ice without a freezer

Here's a fun experiment you can do that will demonstrate the effects that pressure has on the freezing point of a liquid. You will amaze your friends as you do what seems to be impossible, turning water into ice without sticking it in the freezer.

### How To: Isolate a variable

If you're struggling a bit with algebra, check out this video to learn how to isolate a variable. Isolating a variable is a matter of separating and simplifying.

### How To: Find the Height of a Trapezoid.

Step by step directions for finding the height of a trapezoid. Video: .

### 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: 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: Calculate math without a calculator

Before the calculator and even the abacus was invented, there was a little instrument called the human brain that we used to do math. Remember that? While most of us turn to our trusty Ti-84s to do calculus homework or whip out our cell phone calculators to determine how much we should tip at Johnny Rocket's, it can often be much faster to use our own brains, along with a piece of paper and pencil.

### 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 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...

### How To: Simplify fourth roots

In this video the instructor shows how to find out the fourth roots of a number. The properties of fourth root says that for any positive number of a, its fourth roots are real. And for any negative value a, its fourth roots are not real. So split the number inside the fourth root as the product of two perfect squares and then cancel out the power with the fourth root giving its roots. As the fourth roots of a positive number are real, the answer you get is correct. But you cannot find out th...

### How To: Make Your Own Glowing Green Fluorescein (Fluorescent Dye)

Fluorescent dye can be a great addition for decorating around the house for Halloween, especially for a haunted one. Creating your own fluorescent dye is a simple experiment, as long as you've got the proper chemicals and safety gear. Nurd Rage details the chemical process of creating your own fluorescein below.

### How To: Calculate Type I (Type 1) errors in statistics

Need a quick primer on how to solve type-1 error problem in stats? Let this video be your guide. 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. For all of the details, watch this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials.

### How To: Reduce fractions to their lowest terms

This video tutorial belongs to the Education category which is going to show you how to reduce fractions to their lowest terms. For doing any operation with fractions like addition, subtraction, multiplication or division, they need to be reduced to their lowest terms. To do this look at the numerator and the denominator and decide what number can divide both of them. Continue dividing till you can no more divide them. Now you get the lowest term of the fraction. For example, 2/4 can be divid...

### How to Be Your Own SpaceX: Design, Build & Test Liquid-Fueled Rocket Engines

Move over NASA— SpaceX is taking over. Well, not really. But today, the privately funded spacecraft company broke all expectations when their Dragon capsule fell to a soft landing in the Pacific Ocean, completing an undoubtedly successful demo flight of nearly two full trips around Earth. It was the first re-entry of a commercial spacecraft ever, bringing commercial space transportation closer to reality.

### How To: Make lightning using everyday household materials

Make lightning and generate tens of thousands of volts in your own kitchen at home using ordinary household objects! Mr. G demonstrates the amazing Triboelectric Effect and explains the electron exchange via adhesion and separation that makes it all possible.

### How To: Convert Fahrenheit to Celsius with a formula

In order to convert Celsius to Fahrenheit, you will need to use this formula: F = 9/5C + 32. Therefore, you will need to solve for C or substitute values and solve in that manner.

### How To: Find outliers using the Z-score method

If you use Microsoft Excel on a regular basis, odds are you work with numbers. Put those numbers to work. Statistical analysis allows you to find patterns, trends and probabilities within your data. In this MS Excel tutorial from everyone's favorite Excel guru, YouTube's ExcelsFun, the 49th installment in his "Excel Statistics" series of free video lessons, you'll learn how to find outliers with the +/- 3 Z-score rule and the ABS function. See how to do a box plot by hand and in Excel. For th...

### How To: Weld plastic bottle caps together to make your own water vortex

Forget a message in a bottle, how about your own water vortex!? This simple, step-by-step video shows you how to 'weld' two plastic bottle caps together so you have a tight, dry seal for your very own home water vortex. You'll need a heating element, a non-stick pan, some 2 liter plastic bottles and several extra plastic bottle caps. Now you can hold a vortex in your very own hand.

### How To: Make DIY Nitrogen Triiodide from ammonia & water purification iodine crystals

Nitrogen Triiodide is a very powerful contact explosive, but like most fun chemicals is not readily available to the general public cheaply. If you want some and have some chemistry skills, watch this video to learn how to make Nitrogen Triiodide at home out of household ammonia and water purification iodine crystals.

### HowTo: DIY Glow Sticks

WonderHowTo favorite (and pal) NurdRage brings us another great science tutorial. Making glow sticks at home is not necessarily cheaper, but it's a great science project. Check out the video below to learn not only how to make the glow sticks, but also all about fluorescent dyes (and why Mountain Dew will not do the same thing). Previously, NurdRage Shatters Mysteriously Procured Human Heart.

### How To: Square numbers faster

Become Harry Potter of Mathematics. In 5 min. reprogram your mind to calculate faster than the Calculator itself. Impress others with your super-fast mental mathematics.

### How To: Find the volume of a cube, cylinder, pyramid or cone

This video shows the method to find the volume of a cube, cylinder, pyramid or cone. Volume is equal to the multiple of the area of the base and the height or V=(base area)(height). Starting with the cube, the volume= [(side)(side)](side) or side cube or side^3. In the video side=50m or V=125000 cubic centimeter. Volume of the cylinder= [(pi){(radius of base)^2}](height of cylinder) or V=(pi)(r^2)(h). Substituting the values, V=pi(2^2)(4) cubic inches or 16pi cubic inches. Volume of a pyramid...

### How To: Divide fractions by multiplying by the reciprocal

Having a hard time with dividing fractions? Learn the simple steps it takes to complete these division problems. With this instructional educational video you learn the golden rule, "NEVER DIVIDE FRACTIONS" Instead you multiply by the reciprocal which is the flipped version of the original fraction. Then from there is simple, you just multiply straight across like any other multiplication problem then just simplify. This one minute video will take you through all the steps and give you an exa...

### 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: Estimate probabilities with the empirical rule

Learn how to use the empirical rule (or 68-95-99.7 rule) to estimate probabilities for normal distributions in statistics. 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 fre...

### How To: Find the highest common factor (or HCF) of two numbers

Need to figure out the highest common factor of two numbers? 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: Get lithium metal from an Energizer battery

Watch this science video tutorial from Nurd Rage on how to get lithium metal from an Energizer battery. They show you how to get Lithium Metal from an Energizer Ultimate Lithium battery.

### How To: Calculate standard deviation with graphing calculator

This video tutorial is in the Education category which will show you how to calculate standard deviation with TI graphing calculator. First you got to enter the data in to the calculator. Go to stat and click on enter. This will edit a list. Now you type in these numbers: 50, 20, 33, 40 and 55. Then press stat and click on enter. This will bring up the 1-var stats page. Press the "2nd" button and L1, because all our data is in L1. Click on enter and you will get all the data that you will nee...

### How To: Multiply and divide three rational expressions

In this video, the instructor shows how to multiply and divide rational expressions. To solve a rational expression that contains many terms, solve step by step by following the order of operations. Order of operations advises one to work the parenthesis part first; so solve the equation inside the parenthesis first. If you have a fraction multiplied by another fraction, first factorize the numerator and denominator of both the fractions. Cancel out any common factors simplifying it. In case ...

### How To: Deflate and Reinflate Balloons Using Liquid Nitrogen

In this "Quick Clip," I tried dunking inflated balloons into a container filled with liquid nitrogen until they were completely flattened and seemingly destroyed. Once out of the liquid nitrogen, the balloons come back to life and reinflate on their own—without even touching them!

### How To: Change fractions to decimals

In this tutorial, we learn how to change fractions to decimals. Once you learn how to do this, it can help you learn more levels of math. Start out with easy problems and work your way up to more difficult ones. First, try rewriting the equation. Take your top numerator and divide it out by hand by your denominator. After you have done the long math for this, the number that is on the top of the division sign will be your answer. You will need to have a good sense of what numbers add into wha...

### How To: Find the volume of a pyramid

In this tutorial, we learn how to find the volume of a pyramid. The equation to figure out how to find the volume of a pyramid is 1/3ab x h. When you begin, find the height, length, and square feet of the pyramid, then fill these into the appropriate spots in the equation. Once you find this, you will be able to find the correct number of the volume of the pyramid. After this, make sure you have the correct labels on the answer that you get from the equation you filled out. When finished, you...

### How To: Use a three-way stopcock in the chemistry lab

For your chemistry experiments, you'll eventually need to know how to use a stopcock. Well, this science tutorial, interactive animation will show you how to use a three-way stopcock in the chemistry lab.

### How To: Understand chemistry & chemical change

This video tutorial is in the Education category which will show you how to understand chemistry and chemical change. The question here is 10g of Mg ribbon reacts with 0.15 mol decimeter cubed of hydrochloric acid at 25 degree Celsius. What is the balanced equation for this reaction? When magnesium reacts with hydrochloric acid, you will get magnesium chloride and hydrogen. So, the equation will be Mg + 2HCl = MgCl2 + H2. Mg is in group 2 of periodic table and has a valance of 2, whereas Cl i...

### How To: Change fractions to decimals to percents

If you're looking for a quick way to refresh your memory or that of your students regarding percents, decimals and fractions then this video is a sure fire way. While it is a bit fast paced, this tutorial offers a step by step reintroduction to the math part of ourselves that we each adore. Infused with minor comedic scenes to keep the viewer interested Roadside Ron does a thorough job in teaching the most basic of math steps which opens the window for other math problems. Clear and concise t...

### How To: Make Your Own Homemade Glow Sticks

The first glow sticks were patented by the US Navy in the 70s, but back then, they were called "Chemiluminescent Signal Devices." Today, glow sticks are still used by the military, emergency services, campers, divers and, of course, ravers. I may be done with the glow-in-the-dark parties from my college days, but I still think glow sticks are pretty legit, and always thought it would be awesome to make some for myself. Talk about a cool application for all those boring chemistry lectures.

### How To: Make Water Freeze into Ice Instantaneously

Have you ever seen water freeze instantly? This "Quick Clip" shows some of my personal experiences with making instant ice using a bottle of water supercooled in a freezer.