# Hot Education Posts

### 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: Calculate probability in "at least one" problems

Calculating probablities can be used to help us make decision. PatrickJMT explains how to calculate probability in an "either A or not A" scenario. The probability of A plus the probability of not A is equal to one. Therefore, the probability of A is equal to one minus the probability of not A ; P(A)= 1 - P(not A). The probability of a major earthquake in San Francisco over a period of time is used as an example. The probablity of an earthquake of a magnitude of 7.5 or greater in San Francisc...

### 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: 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: Learn Calculus in 20 minutes

Did you sleep all semester in your Calculus class? Are you just waking up now to realize you have a test on Monday and that you're totally screwed? Well, luckily you can learn an entire semester worth of Calculus in just twenty minutes... or at leasts that's the hope.

### 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 green luminescent phosphorescent glow powder

It's a stormy winter night, and you're electricity goes out. You could grab some candles to add a little light to your life, or you could use glow-in-the-dark chemicals for a cool luminescent.

### 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: Calculate the age of the universe w/ Hubble's constant

This is a great instructional video on how to calculate the age of Universe from Hubble's constant. The speed the galaxy moves away from us is directly proportional to the distance from us. Now think of big bang theory. Hubble's constant is equal to velocity over distance. 1 over Hubble's constant is equal to distance over velocity that is equal to time. Time equals to 1over 71. If you change it into all the same units words it is one over 71000 or 3.09x 10 to the power of 22. It is 3.09x10 t...

### 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: 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.

### 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: 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: 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: 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: 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 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: 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: Use derivatives to find slope in calculus

Need help figuring out how to work with derivatives in calculus? 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 use derivatives to f...

### How To: Find a data point (Xi) with the Z-Score formula

In this free video math tutorial, we learn how to use the Z-Score formula to find a data point (Xi) in statistics. With mathematics, as with anything else, not everyone progresses at the same rate. Stats is no exception. Happily, in the age of Internet video tutorials, this isn't a problem. Those who progress quickly can go beyond what's being taught them and those who are struggling likewise have all the time in the world to catch up. Whether you need help finishing your homework or studying...

### How To: Convert percents into fractions and decimals

This video shows you how to convert percents to fractions and decimals To convert percent to decimal or fraction it is important that we know the meaning of percent which is per 100. So to convert a percent to fraction is simply to put in over 100 and simplify. Now to convert percent to decimal is to move the decimal point two spots to the left. if you don't see a decimal point, it is understood that is behind the last digit of the number.

### How To: Convert decimals into fractions

In this simple tutorial the author shows the basic arithmetic operations like converting a terminating decimal into a fraction. He says that the complexity depends up on the number we are converting. He asks us to imagine the decimal as a fraction with an imaginary denominator of value one. Now he intends to remove the decimal in the numerator by moving it to the right of the number and he tells us to similarly move similar number of decimal places in the denominator to maintain the original ...

### How To: Create Toxic-Free Green Slime (Makes a Perfect Kid Toy)

This slime is toxic-free and can be used as either a kid toy or to make a great prank. This slime can be made in just a few minutes and doesn't require much for materials. Our video explains in detail how to accomplish this project with step-by-step instructions.

### How To: Compute a square root using the geometric method

With mathematics, as with anything else, not everyone progresses at the same rate. Happily, in the age of Internet video tutorials, this isn't a problem. Those who progress quickly can go beyond what's being taught them and those who are struggling likewise have all the time in the world to catch up. With this free video math lesson, you'll learn how to calculate the value of a square using using geometry.

### 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: Experiment with circular motion

This video shows various experiments with circular motion. In Dr. Carlson's Science theater he uses water, a lit candle, and a piece of paper to show the ways that circular motion causes gravitational pull. The water in a glass doesn't spill as it is spun around 360 degrees in a circle, even upside down. The flame on the candle was pulled toward the center when spun around. The piece of paper becomes a paper saw and was able to cut wood when spun. He not only demonstrates centrifugal force wi...

### News: Reverse Arrow Trick - Amazing

When the arrow is moved to a particular distance behind the glass, it looks like it reversed itself. When light passes from one material to another, it can bend or refract. In the experiment that you just completed, light traveled from the air, through the glass, through the water, through the back of the glass, and then back through the air, before hitting the arrow. Anytime that light passes from one medium, or material, into another, it refracts.

### How To: Make sodium silicate from drain cleaner and gel beads

Watch this science video tutorial from Nurd Rage on how to make sodium silicate from drain cleaner and gel beads with Dr. Lithium.

### How To: Make aluminum nitrate nonahydrate

Aluminum nitrate nonahydrate is a crystalline hydrate - a salt of aluminum and nitric acid - Al(NO3)3·9H2O. It's used for a variety of things such as antiperspirants, corrosion inhibitors, and petroleum refining, or… glow-in-the-dark powder. Watch this science video tutorial from Nurd Rage on how to make aluminum nitrate nonahydrate with Dr. Lithium.

### How To: Isolate the sugar in a can of soda

In this video from ScienceOnTheBrain we learn how to isolate the sugar in a can of soda. To find out how much sugar is in soda, pour a can into a pot and boil it until all the water is gone. You will be left with the sugar, and then you can weigh it. First weigh your pot before pouring the soda in. Now boil the soda on the stovetop. When the water evaporates, you'll be left with a syrupy sugar. A can of soda has 39 grams of sugar in it. That equates to about 7 1/2 teaspoons. Fruit juice conta...

### How To: Find the average value of a function over an interval

When you have to find the average of two or five numbers then you have to add all the numbers and then divide then by two or five respectively. However in the case of the function you have infinite many values over any interval. But it is not possible to add all and then divide by infinity. Therefore you have to calculate in a different way. Imagine that you have to find the average of y=f(x). Then you have to average it from the interval from ‘a’ to ‘b’. The inner area under the curve shall ...

### How To: Make a candle wax explosion

In this video, you'll see how and why wax can be a deadly. This is how it works,When the test tube is submerged in cold water, the glass forms tiny cracks. The Water enters gets into the tube and vaporizes causing a micro explosion. The hot wax is then ejected from the tube quickly as oxygen is displaced from the tube itself. Be careful, and make sure to be as safe as possible when trying this experiment at home.

### How To: Use gentian violet to reveal latent fingerprints

This video would be very interesting for those seeking careers or those interested in the field of criminal science. This field involves forensic science. The video explains to us how to use gentian violet in order reveal latent fingerprints. He explains to us the experiment he is about to do before he does it. Genetian violet is a type of dye solution that can be very helpful in retrieving fingerprints. Safety goggles and gloves should be worn at all times.

### How To: Make strontium nitrate

Watch this science video tutorial from Nurd Rage on how to make strontium nitrate. They show you how to make strontium nitrate from strontium carbonate and nitric acid.

### How To: Use a desiccator in the chemistry lab

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

### How To: Make a foamy elephant toothpaste chemical reaction

Try out this science experiment... a classy chemical demonstration. Watch this video tutorial to learn how to make a foamy elephant toothpaste chemical reaction. There's a reason why they call this elephants toothpaste.

### How To: Factor trinomials with the "swing method"

This is a very interesting educational video on how to find the factor trinomials using the swing method. Let us take an example and find the factor trinomials for 2xsquare-13x-45. Let us use the swing method. So now we will get 2xsquare -13x-45. You have to find the suitable factors of 90. It is 18 and 5. If you multiply 18 by 5 you will get 90. You will get (x-18over2)(x+5over2). The final answer is (x-9)(2x+5). Now we have found out the factor trinomials of 2xsquare-13x-45. This swing meth...

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

In this video the instructor shows how to find the slope of a line given two points that like on the line. Slope of a line is the measure of the steepness of the line compared to the angle made by the line with the x-axes. A line with positive slope slants forwards and a line with a negative slope slants backwards and a line parallel to x axes has zero slope. So if you are given two points (x1, y1) and (x2, y2), the slope of the line passing through those two points is equal to m = (y2 - y1)/...

### How To: Reduce Static Electricity

Static electricity might seem like magic but you don't have to be a wizard to get rid of it. There are simple steps you can take to reduce the amount of static electricity in the air or on you by using some items you probably have at home.

### How To: Make a quick and easy compass

This is an easy & simple way to make your home made compass using stuff that can be found in every home. You will need a magnet, a paper clip, a glass of water and a piece of paper. Check out this instructional science video to learn a a quick and easy method of making your own compass. This is a great science experiment to perform with the kids. Make your own compass by following the simple instructions in this science tutorial video.