# Hot Education Posts

### 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: 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: Cite a website with hard to find author or date info

Sometimes it can be difficult to find information essential to a citation on a webpage, like an author or a date. Here are some steps you can take to make up for this lack of information.

### How To: End a letter

Not sure how to close an important letter? Convey a powerful meaning to readers by choosing the right sign-off. In this video, proper etiquette to close a letter is gone over.

### How To: Make oxygen from permanganate and hydrogen peroxide

C For Chemistry delves into the chemistry of science experiments. This chemist knows what he's talking about. These chemistry experiments are not only fun, but very educational for all of those interested in scientific chemical reactions and properties.

### How To: Make neon green water glow

Check out this how-to video for making water glow, or for making glow water (it's pretty much the same thing). Get ready for that fun, neon green color. You will need a cup on gloves, among other things, to make glow water. Use a black light.

### News: Coca Cola vs Coca Cola Zero - Sugar Test

Just how much "zero" is Zero? What happens if you boil these popular drink for 20 minutes or so? Watch this video and you'll be surprised by what you get after the water evaporates.

### How To: Rationalize square roots

In this tutorial, we learn how to rationalize square roots. You cannot have square roots in the denominator of an equation. You need to multiply so the square root goes away. You can do this by multiplying the top and bottom of the equation by the bottom denominator. From here, this will make the square root go away, so your equation will be normal numbers. After you have done this, you will have the equation answered and you will be able to simplify it to find the end answer. You can do this...

### How To: Factor quadratic trinomials by trial and error

Want to know how to factor quadratic trinomials in algebra? One easy way is through trial and error. Watch this free video algebra lesson to see how. 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 factor t...

### How To: Multiple and divide rational expressions

This video walks you through the steps of multiply and divide 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: 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: Factor a trinomial with negative leading coefficient

In this video the instructor shows how to factor a trinomial with negative leading coefficient. Most of the students are confused when they have to factor a trinomial with a negative leading coefficient. But there are many ways to solve these kind of problems as shown in this video. One way you can do is that take out the greatest common factor (GCF) of -1 from the equation. So pulling the -1 gives you the original trinomial with all the signs of the terms changed. Now go on and factor the ne...

### How To: Find slant (oblique) asymptotes of rational functions

In this educational video the instructor shows how to find the slant asymptotes of rational functions. Slant or oblique asymptotes occur when the degree of the numerator is exactly one greater than the degree of the denominator of the rational function. The way to find the equation of the slant asymptote from the function is through long division. In this long division you divide the numerator with the denominator by following the long division method as shown in this video. Before dividing i...

### How To: Write the equation of a circle in standard form

Here you'll be shown how to take the equation of a circle, and convert it into standard form. Also, it will be explained just what standard form is, while running through the process of conversion. You'll be able to use techniques to quickly work off the numbers on the equation, one by one, until it's simplified enough to understand. Complicated algebra functions become much simpler when you see these easy to use techniques, that will help you rearrange the equation into a form that is actual...

### How To: Make fire water or "Negative X" (Zn, NH4NO3, NaCl)

C For Chemistry delves into the chemistry of science experiments. This chemist knows what he's talking about. These chemistry experiments are not only fun, but very educational for all of those interested in scientific chemical reactions and properties.

### How To: Make copper sulfate and zinc batteries

Watch this science video tutorial from Nurd Rage on how to make copper sulfate and zinc batteries. They show you how to make the classic copper sulfate and zinc battery using the incredibly easy "gravity" battery design approach. Great for science fairs and similar projects this battery can be used to explore many basic concepts in batteries.

### How To: Demonstrate Newton's law of inertia

This short video clip shows seven demonstrations of Isaac Newton’s first law of motion– the law of inertia. Newton’s law of inertia states that objects moving at constant velocity will continue moving at constant velocity, unless acted upon by an outside unbalanced force. Six of these demonstrations (excluding number six) are from Tik Liem’s book Invitations to Science Inquiry.

### How To: Turn spinach from green to glowing red

Chlorophyll glows blood red under a black light. Here is an easy and cheap experiment you can do at home to see the results. Just check out this video tutorial to learn how to take a handful of green spinach, some rubbing alcohol, and a blender to prep the amazing red glowing liquid. Then, just filter it out with a coffee filter and bottle it up. Then, get the black light out and get ready to party.

### How To: Make solid rocket fuel ignition with zinc and sulfur

Once used as solid rocket fuel because the reaction requires no oxygen, sulfur and zinc react vigorously. The reaction with zinc produces flame and a near explosion. Sparks fly and smoke billows in this dramatic chemical demonstration.

### How To: Multiply & Divide Numbers (Basic Elementary Math)

Adding and subtracting may be the easiest of mathematical operations, but once you get it down, multiplication and division can be just as easy. That's why it's called elementary arithmetic. If it were harder, it would be called college algebra or trigonometry. But it's not— it's basic math, and once you get your head around the numbers, you'll never hate math class again! (Okay, maybe you will.)

### How To: Find the perimeter & area of a complex figure

In this video tutorial the author shows how to find the perimeter and area of a complex figure. He shows that a complex figure can be subdivided into standard geometric figures. In the current example he divides the complex figure into a rectangle and a triangle. Now he computes the perimeter by adding the three sides of the rectangle and the two sides of the triangle. Similarly he computes the individual areas of the rectangle and the triangle and finally adds then up to find the area of the...

### 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: 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: Make boric acid from borax

This is a video tutorial in the Education category where you are going to learn how to make boric acid from borax. For this experiment you will need borax (disodium tetra borate) and conc. hydrochloric acid. Take 25 ml of hydrochloric acid and dilute it with 75 ml of water. Next take 6 - 7 gms of borax and dissolve it in boiling water. Now add equal amount of hydrochloric acid. Crystals of boric acid will start forming. They are completely insoluble in cold water. After about half an hour, fi...

### News: What Happens When You Mix Coca Cola and Milk

Interesting reaction coke and milk The reaction of phosphoric acid (V) to proteins in the milk - they are cut and causes a precipitate

### 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: 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: Determine volume measurement

In this how to video you will learn how to measure the volume of solids and liquids. The formula for determining volume is width x length x height.

### How To: Subtract a mixed number from a proper fraction in basic math

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 free math tutorial, you'll learn how to subtract a mixed number from a fraction in basic arithmetic.

### 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 the Slope Given 2 Ordered Pairs

Slope is the change in Y over the change in X. Written out, the formula looks is as follows: (y2-y1)

### How To: Use a Peltier module to create free electricity from heat

A Peltier module allows you to turn heat into electricity. Because you can place it in areas that are normally warm anyway, the electricity created is "free" in a sense, though it does work best when one side of the module is cold and the other is hot. In other words, all you'll need for this project is the Peltier module and a cooler surface such as soil or water, and a warm area such as a well lit window or warm pan.

### How To: Divide and give an answer as a fraction

In this video we learn how to divide and give an answer as a fraction. If you are starting out with a simple fraction, you will simply take the number before the divide sign on the top and the second number on the bottom. If you end up with a number that is able to be simplified, make sure you take it down to it's most simple version possible. You can end up with a top heavy fraction, which means there will be whole numbers involved. Do the division to figure out how many times the bottom num...

### How To: Complete a proof involving segments

This video from Yay Math! is a geometry lesson on how to complete a proof involving segments. He draws a line segment with four points labeled A, B, C and D. The problem is as follows: Given: AC is equivalent to BD. Prove that AB is equivalent to CD. The first statement of proof is the given. Next, you need to define the congruent segments and state that they're equal in measurement. Next, break down the segments: AC=AB+BC, and BD=BC+CD. This is called segment addition postulate. The end of t...

### How To: Solve an equation with a radical under a radical

In this video the instructor shows how to solve an equation with a radical under a radical. If you have an equation with a square root on both sides, with one of the sides having another inner square root under the original square root, it can be a little tricky to solve it.

### How To: Find the equation of a line given 2 points

This tutorial teaches you how to find a mathematical equation of a line given 2 points that exists on the line. The tutorial starts off with 2 points labeled (2,-4) and (3,6). The first step is to determine the slope of the line using the formula given in the tutorial in blue. The slope is then solved as 'm'. Plug the slope and the points into another formula given in green. The tutorial maker provides a tip that one can use x1 and y1 or x2 and y2, however, it must be consistent. After, solve...

### 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...

### Use the quadratic equation: finding the mirror point

In this video the tutor shows how to find the mirror point using a quadratic equation. He says that to graph a parabola you need to find the mirror point symmetrical to the Y-intercept. Now he explains how to find a mirror point using an example with sample values. He begins with saying that the Y-coordinate of the mirror point is same as the Y-coordinate of the Y-intercept. Now you have to find the x coordinate of the mirror point which he shows that it is double the x-coordinate of the vert...

### How To: Purify hydrochloric acid

This video topic was changed. It is now converting muriatic acid to reagent grade hydrochloric acid, HCL).

### 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 ...