# Hot Education Posts

### 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: Make (non-Newtonian) Oobleck from corn starch & water

Mr. O shows his audience in this video how to make oobleck, a slime-like substance which has a variety of unique properties. For this project, you will need a mixing bowl, food coloring, corn starch, a measuring cup, and water. First, color the water with food coloring to a color which is much darker than the color you would like. You will need the correct ratio of water to cornstarch, in a 1 to 2 ratio. Add some water to the bowl and add the cornstarch, then add the rest of the water. Finall...

### How To: Find the formula of a piecewise function given a graph

This video shows how to find the formula of a piecewise function when given a graph. The first step is to write a definition for the graph, which is done by identifying the different domains shown in the graph. The second step is writing formulas for each domain specified by the lines in the graph. The point-slope formula is used to identify the slope and y-intercept for the leftmost domain, which has a sloped line. A point and horizontal line make for simpler equations in the other pieces of...

### How To: Rip a Penny in Half

No, we're not lying. But before you try and tear a plain old penny in half, you should probably watch this video first or you may hurt your fingers. While ordinary pennies are very, very difficult to rip, if you get rid of the zinc core you are left with only the thin copper shell, which is itself very easy to tear apart.

### How To: Do normal probability calculations on a calculator

Probability computation is a complex process and even using a calculator can be difficult. But normal probability calculations can be performed quickly with the help of calculator once you know how to use it. So when you have to calculate a probability from a normal distribution you can use the functions on your scientific calculator. You can use the normal CDF function from you calculator to compute the area under a normal curve. The function requires lower band and upper band values, the me...

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

To write the sum or difference of logarithms as a single logarithm, you will need to learn a few rules. The rules are ln AB = ln A + ln B. This is the addition rule. The multiplication rule of logarithm states that ln A/b = ln A - ln B. The third rule of logarithms that deals with exponents states that ln (M power r) = r * ln M. Using these three rules you can simplify any expression that involves logarithms to arrive at a single logarithm. The instructor shows how to apply these rules to a f...

### 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: Find the standard error of the mean

In this video the tutor explains about the standard error of the mean. He starts explaining by drawing the diagram of a distribution and now he takes ten samples from the distribution and starts plotting them. He says that in theory if we do it infinite times then we can obtain the sampling distribution of the sampling mean. For the example he takes the number of samples as 10. Now depending on these values of n we can get different sampling distributions. Now he intends to find the mean of t...

### How To: Find the slope's unit of measure

This educational video from free math tutoring shows how to calculate the slope of a line and assign units to the answer obtained. This video assumes that the viewer is familiar with the concepts of axes and co-ordinate geometry. The narrator uses a commonly used formula to calculate the slope of the line in the first section of the video. In the second section, the narrator demonstrates how to assign units to the answer, as per the question asked.

### How To: Make Soap Out of Guava Leaf Extract for a Science Investigatory Project

In our personal experience, the hardest part about a science investigatory project is simply coming up with a good idea. And we suggest that for your investigatory project you find a topic that's both novel and useful.

### How To: Do balloon and bottle pressure experiments

Requirements: 2 soft drink bottles, 2 or 3 balloons , screwdriver. First take the balloon and check the balloon.

### How To: Find the area of an oblique triangle using formulas

In this tutorial the instructor shows how to find the area of an oblique triangle using different formulas. To find the area of an oblique triangle there are different formulae. The first formula to calculate the area of a triangle is area A = (1/2) * a * b * Sin(C), where a and b are the lengths of the two sides of the triangle and C is the value of the angle of the triangle that lies in between the two sides a, b. Now substitute these values in the given formula to find the area if you have...

### How To: Find and sketch the domain of a multivariable function

Looking for a primer on how to find and sketch the domain of a function z = f(x, y) in calculus? Learn how with this free video calc 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: Make blue phosphorescent glow-in-the-dark powder

Making a blue glowing substance is easy, as long as you already know the secret to making green luminescent phosphorescent glow powder. By watching the green glow-in-the-dark procedure, you know that you will need strontium nitrate, aluminum nitrate, europium and dysprosium nitrates, and nitric acid. That will make a green glow, but if you want to make a blue version, it's a relatively easy fix...

### How To: Identify characteristics of a sample during a survey

To identify characteristics of a sample in your survey, there are many factors to consider of your samples. The first four characteristics you need to focus on are gender, age, income level, and education level. All four of these characteristics must be proportional to that of the population. You also need to consider the geographic location. Only take samples from the immediate geographical area. Finally, an important characteristic of the survey is the sample size. You do not want to ask to...

### How To: Be a human calculator

Before we had the calculator and before we had the abacus we had the human brain to complete our math problems for us. Remember that? Well, it seems that few of us do, resorting to calculators on our phone for elementary subtraction problems and multiplication.

### 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 ...

### How To: Prove a triangle inscribed in a circle is right angled

When a triangle is inserted in a circle in such a way that one of the side of the triangle is diameter of the circle then the triangle is right triangle. To prove this first draw the figure of a circle. Now draw a diameter to it. It can be any line passing through the center of the circle and touching the sides of it. Now making this as the side of a triangle draw two lines from the ends of the diameter to a point on the circle. Now join the center of the circle to the other vertex of the cir...

### How To: Find the equation of an ellipse given a graph

Notes College Algebra teaches you how to find the equation of an ellipse given a graph. You first want to find out the center of the ellipse, which in the video is (2, -3). The major axis is parallel to the X axis. The equation is (x - h) squared/a squared plus (y - k) squared/a squared equals 1. A is the distance from the center to either of the vertices, which is 5 over here. B is the distance from the center to the top or bottom of the ellipse, which is 3. You then use these values to find...

### How To: Graph a quadratic function in factored form

This video deals with solving quadratic functions. It does not involve the use of the quadratic equation; rather, only factored equations are used. The speaker starts out with a factored quadratic equation. The speaker goes on to do the mathematical steps necessary to find both the x and y intercepts of the quadratic function at hand. The author then continues on with the example to find the function's minimum. Next all of the points that have been solved for are plotted and the function is s...

### How To: Find the length of a segment using the midpoint II

First of all in the given question you have to write down the values of the total length of the line segment, PS=15. The length of the line segment, QR =3. Now you have to find the value of line segment RS. Because you know that the Q is the midpoint of the line segments PQ and QS must be equal. Therefore you can find out the length of the half of the segment using the midpoint. Subtract the value of QR from QS. Given that segment PS=15 and Q is the midpoint, you can conclude segment PQ=7.5 a...

### How To: Find the area of a triangle with decimal measurements

This is an introductory educational video that shows how to find the area of a triangle with decimal measurements.

### How To: Pass the test when you haven’t read the book

You kept putting off reading the book, now the test is tomorrow and you haven’t even cracked the cover! Here’s how to pass anyway.

### How To: Shrink plastic with household materials

In this video, we learn how to shrink plastic with household materials. You will need: tin foil, plastic container, scissors, glove, and colored markers. To start, you will preheat the oven to 325 degrees. Then, cut a piece of the plastic out in a square shape. Next, draw whatever you want onto your piece of plastic. Make it as colorful as you would like to! When finished, put this in the oven using a glove. Make sure it's on the foil when you put it in. Then, leave it in for less than a minu...

### 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: 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: Make a tomato glow in the dark (FAKE?)

F for FAKE. This video has been labeled a "Faux-To". Commonly contested as bogus science, we believe this video to be a hoax. What's your opinion? Comment below.

### How To: Do a flaming ice experiment

In this fascinating "how to" video, you will see how a simple process creates the illusion of ice that is burning. Only a few items are needed to enact this scientific experiment. As the narrator describes, "Calcium carbide reacts with water to form acetylene gas." To illustrate, the video shows a bowl of ice cubes, to which the special ingredient is added. As the ice melts into water, it reacts with the calcium carbide, forming the high flammable acetylene gas, which is often used in welding...

### How To: Determine whether 2 triangles are similar in geometry

Looking for instructions on how to determine whether two triangles are similar in geometry? 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: Multiply three or more fractions or mixed numbers

Want to multiply three or more fractions or mixed numbers? It's easy: Turn the mixed numbers into improper fractions. Cross cancel where you can. Multiply straight across. (simplify and reduce if you did not completely cross cancel). This free video math tutorial presents a complete walkthrough of the process. 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...

### How To: Solve Word Problems Involving Volume of a Pyramid

Learn how to solve geometry word problems. For example, how would you solve the following problem?

### How To: Make water rapidly crystallize

A seed crystal is dropped into an unstable supersaturated solution of sodium acetate NaC2H3O2 and it completely crystallized in front of your eyes. This demonstration is prepared by heating 700 grams of sodium

### How To: Make a liquid barometer

This video will show you how to construct a barometer using isopropyl alcohol.

### 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: Make elephant toothpaste with detergent, hydrogen peroxide & potassium iodide

We all know what elephant toothpaste is, but what's the best way to make this massive growing foam? Dr. Lithium from NurdRage has answers. He'll show you the best way to reproduce this chemical reaction to get the best foaming action! This is a classic science class demonstration.

### 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: Translate a shape

Learn how to translate shapes with a few simple steps. - First step: Find the new verticals under the transformation which are T3,2. Values are A=(-5,-8), B=(-3,-4), C=(-8,-3), D=(-6,1). Find the points of the verticals on the graph and connect the points one by one until you can get one shape.

### 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: Make a Paper Plate Speaker That Actually Works for Under $1

Back in 2007, YouTube user HouseholdHacker posted a parody video on how to make a high-def speaker for under a buck. MythBusters took on the challenge and busted it.

### How To: Find extra points for a parabola (quadractic equation)

This is a mathematical educational video on how to find extra points for a parabola. In the first two examples there is no need for finding extra points as they have five points and have zeros of the parabola. In example 3 we need to find extra points. The equation is y=4xsquare-4x+4. You can take x= -1 and get the value for y. You will get a point now. Similarly you can substitute -2 for x in the same equation and get the value for y. Now you get another point. Now you can draw the parabola.