# Hot Education Posts

### How To: Calculate weight if given the mass

The video shows how to calculate weight if the mass is given and vice versa.Later on in this unit you will learn about Newton's laws of motion and Newton's second law of motion gives us a way to change mass into weight and vice versa.This law will tell you what is happening to objects when the net force on the object is not equal to zero and the easy way to say what will happen is that the object will accelerate.But how much the object accelerates depends on two things,firstly the mass of the...

### 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: Make potassium nitrate from instant cold packs

Watch this science video tutorial from Nurd Rage on how to make potassium nitrate from instant cold packs and potassium hydroxide.

### 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: 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: 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 area of a parallelogram using geometry

The video shows us how to find the area of parallelogram using geometry. Here in this video it is done by using an example where the parallelogram is given ABCD. The area of the parallelogram is base times height (bh). Here the base is given as 15 but the height is not known but it is represented by the segment BD. To find the value of h, let’s use right triangle BDC on the right side of the figure. Since base is 15 and the opposite side of the parallelogram is congruent, the hypotenuse of th...

### How To: Make fireballs you can hold in your hand

This flame you CAN hold, without burning your skin off. Learn to make fireballs you can hold in your hand. This amazing video tutorial shows you how to do it. All you'll need for this little science experiment or fiery weapon is 100% cotton cloth, scissors, lighter fuel, cotton string, and a needle. Be careful to follow the directions in this how-to video carefully otherwise you'll really be playing with fire.

### How To: Translate a sentence into math symbols

We will be translating the sentence "twice y differs from 5 by more than two, “into a mathematical equation. The word twice generally means two times, so 2*y (because y comes next in the sentence). Differs normally means is different and a difference from something in a mathematical sentence means subtraction most of the time, thus minus five. We don't know if we’re talking about below 5 or above 5 on the number line, so we put absolute value around the equation. More than implies a greater t...

### How To: Cancel out in basic algebra

This video gives you brief tutorial on simplifying expressions, or canceling out common factors. He starts out by answering the question "What is canceling?" and demonstrates a basic example. You find the greatest common factor between the numerator and denominator, which you then divide both by. This can also be done if you have variables in your fraction. He then shows it can be done the same way if you have binomials in your fractions. However, you must be careful that the denominator does...

### How To: Find the value of a variable in an algebraic equation

Need help figuring out how to solve simple algebraic equations? 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: 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: 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: 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: Dissolve the shell from a hard-boiled egg with Coca-Cola

If you're a coke fiend, then you may not want to watch this, because you may become faced with a perilous decision— "Should I stop drinking soda?"

### How To: The 5 Best Dry Ice Party Tricks & Pranks

There's no reason to wait for Halloween to play with dry ice. It definitely creates a creepy fog-like effect when you add a little water to it, but there are some other really cool things you can do wit dry ice. Here are just 5 non-Halloween ways to use dry ice for tricks or pranks.

### How To: Create a small explosion with calcium carbide

In order to create an explosion, using Calcium Carbide, you'll need the following: calcium carbide, water, a dropper, and a lighter.

### How To: Solve a line integral over a closed path

Line integrals will no longer be the feared terrorist of the math world thanks to this helpful guide from the Khan Academy. Marvel at the ease in which the integral is taken over a closed path and solved definitively. Then take out a sheet of paper and see if you can do the same.

### How To: Calculate electrical power

This video introduces the formulae for watts in an electric circuit, P=IxE, P=I^R, and P=E^/R. It also explains how P=I^R and P=E^/R are algebraically derived from P=IxE and Ohm's Law.

### 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: 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: 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: Simplify a complex fraction w/ binomial denominators

To simplify a complex fraction, turn it into one fraction on the top divided into a fraction on the bottom. Once this is complete, you will turn the division into the two into a multiple by the reciprocal, factor, and then cancel. To make a division, find the lowest common denominator of both the top and the bottom. Once you get this division equation, look carefully at the equations. If something can be easily canceled, go ahead and cancel it out at this time. If you cannot cancel anything a...

### How To: Make copper metal from copper sulfate

This free video science lesson from the Home Scientist demonstrates a simple technique for creating ammonium chloride from hydrochloric acid and ammonia. For all of the relevant details and detailed, step-by-step instructions, as well as to get started trying this experiment yourself, watch this home-science how-to.

### How To: Describe a linear system without graphing

This tutorial looks at how to describe a linear system without actually graphing it. In order to do that, you will need to convert both equations of a problem into the Y=mx+b format. Once you have done this, you will be analyzing the m and b values. There are a few rules to follow. If the slopes (or m) and the Y intercepts (or b) are equal, there are an infinite number of solutions (or dependent equations). A second rule is if the slopes are equal and the Y intercepts are different, then the ...

### How To: View the universe on a Meade DS-2000 Series Telescope

All you science and astronomy nuts out there, pay attention, this detailed video tutorial series will tell you everything you need to know about using the Meade DS-2000 Series Telescope to ogle the universe.

### How To: Derive the area of a circle

This video is about deriving the area of a circle of radius 'r' using polar co-ordinate. First, we draw a circle and its radius 'r'. Then draw another radius close to it, so that it forms a small triangle-like figure. To find the area of the complete circle, divide the circle into similar small triangles. The area of each triangle is given by half the product of its perpendicular and the base. We give the angle between the two radii as d?. We get the area of the small triangle by substituting...

### How To: Graph using the intercept method

You can draw intercept in graph. The teacher took 4x + 3y =12 for solving using intercepts and told that the standard form of the equation should have X and Y terminal at the left side and constant at the right side.

### How To: Evaluate factorials with a TI-83 calculator

The factorial of a number n can be defined as the product of all positive integers that are greater than 0 but less than or equal to n.

### How To: Find how many toothpicks will be needed to form the nth figure in a sequence

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 employ inductive reasoning to determine the number of toothpicks you'll require to generate the nth (e.g., the 50th) figure in a sequence of figures.

### How To: Draw a rhombus from Geometry

In this video the author shows how to draw a rhombus when given with the values of long diagonal (D) and a short diagonal (d). Now he draws the long diagonal of size D horizontally on a sheet of paper. Now he points the mid point of the line as he explains that the diagonals of a rhombus meet at midpoints. So now he takes the ruler and draws an another line perpendicular to the first line through its marked mid point such that the length of the perpendicular line is d/2 both above and below t...

### How To: Make iodine from hydrochloric acid and H2O2

Watch this science video tutorial from Nurd Rage on how to make iodine from an alkali metal iodide, hydrochloric acid (HCI), and hydroxide peroxide (H2O2).

### How To: Make a pH indicator out of red cabbage

In this video, we learn how to make a pH indicator out of red cabbage. Red cabbage will work because when it absorbs an acid then it changes color and reflects light differently. To do this at home, try to add different types of acids to the cabbage. Start off by putting the cabbage in the blender, then make sure it's shredded. Now, put it in a jar with some boiling hot water. Shake up the jar, then place the water into some separate cups. Now, add chemicals into the juice and depending on th...

### How To: Experiment with pressure using a vacuum

In this video Dr. Carlson does several experiments to illustrate how a vacuum works. A vacuum is created when all the air is removed from an object.

### How To: Determine if a point lies on a line in standard form

In this video, we learn how to determine if a point lies on a line in standard form. In order to do this, you will need to substitute the X and Y value with the ordered pair that is given. The X value is the first number and the Y value is the second number. Re-write your equation, substituting in the numbers to the appropriate spots. Now, simplify the equation by doing multiplication with the negatives and positives (if given). When you get through the equation, you will end up with the solu...

### How To: Solve advanced ratio problems in algebra

Need to know how to solve complex ratio problems in basic 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). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn a system for finding solu...

### How To: Derive a quadratic equation, given the roots

This video shows you how to get the quadratic equation for the quadratic function with roots; (5,0), (12,0) which passes through the point(8,6). It shows a man solving this problem using a black board and chalk to clearly demonstrate the method of plugging in the respective coordinates to arrive at an answer. After watching this video, any person over the age of twelve will know how to use quadratic functions to derive quadratic equations and solve mathematical problems with this particular m...

### How To: Make verdigris with copper and vinegar

In this tutorial, we learn how to make verdigris with copper and vinegar. Verdigris is a compound of copper that is blue and powder. You will need: copper metal, vinegar, a big jug, and a small beaker. Now, place the small beaker inside of the jar, then fill the bottom with vinegar. Next, put the piece of copper metal inside of the jar making sure it sits inside the small beaker. Seal this and put it in a safe and dry place. Leave it for a good month, then when you come back you will have a n...

### How To: Make liquid sculptures from a handwarmer

Learn how to make liquid sculptures from a hand warmer in simple steps. First buy an instant reusable hand warmer which has sodium acetate in it and keep it ready. Now use 4 packets of the hand warmer and stir them out with water. Transfer them to a bottle and keep it aside. Take a sodium acetate crystal from a used hand warmer and place it in a plate. Now pour the liquid slowly on the crystal and you can see the liquid turns solid as you pour it. Design your masterpiece using all the liquid....

### News: Jane Goodall Was a Babe (and One of History's Greatest Conservationists)

National Geographic recently published a retrospective of the lovely Jane Goodall, one of the world's most accomplished conservationists. The feature includes every image of Goodall to ever appear in the magazine for the past fifty years.