### 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 ...

### How To: The Best Investigatory Projects in Science: 16 Fun & Easy Ideas to Kickstart Your Project

Most of us have conducted an investigatory science project without even knowing it, or at least without knowing that's what it was called. Most science experiments performed, from elementary to high school students and all the way up to professional scientists, are investigatory projects.

### How To: Build a Simple Paper Bridge as a Science Experiment

Every day we pass bridges, whether it's a foot bridge, a highway overpass, a span over water, or a viaduct over a valley. We pass on these structures without even thinking of the engineering genius that went into their design and construction, let alone the science behind their strength.

### How To: Make This Amazing 9-Layer Density Tower from Things Found in Your Kitchen

Ralph Waldo Emerson once observed that "the seed of science" was "wonder," and taking a look at this nine-layer liquid tower from Steve Spangler's Sick Science! channel, one can't help but do just that — wonder. How is this possible? Is this magic or what?

### How To: Make elemental sulfur (sulphur)

This video tutorial is in the Education category which will show you how to make elemental sulfur (sulphur). The chemicals you need are nitric acid and sodium thiosulphate. The reaction produces toxic SO2 gas so keep it coved with a watch glass. Put 12.9 grams of sodium thiosulphate in a beaker and dissolve it in minimum amount of water. Pour about 15ml of nitric acid in to the beaker. Let it sit in a warm place for a couple of hours and the sulphur will settle at the bottom of the beaker. Th...

### How To: Find a number given Its percent

This how-to video is about how to find a number when its percent is given. This video is really helpful and effective in finding the number when the percent is given, the following steps are explained in the video to find the number when its percent is given:

### 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: Understand the Pythagorean Theorem

In this video Ken teaches you about the Pythagorean Theorem. The Pythagorean Theorem is used to find the missing length of a side of a right triangle. By watching this video, you will learn how to find any the length of any side by using a simple mathematical formula. Ken walks you through various examples changing the dimensions of the triangle you are solving as well as changing the side you are solving. Ken even includes a real world application to further your understanding of the Pythago...

### How To: Calculate square roots on paper the easy way

Perhaps not as easy as using a calculator, but easy nevertheless! 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 find square roots by hand.

### How To: Multiply and simplify square roots

In this tutorial we learn how to multiply and simplify square roots. When you multiply square roots, you will first need to put them under one radical. From here, you will need to factor out what you have. Once you find a perfect square, find the square root of it. You can either write these as all separate equations or pull the perfect root on the outside of the other parts of the equation. Do the math until you find what you are left with. From here, you can do basic math to find what's lef...

### How To: Dissolve ruthenium metal with household bleach

You've manage to get your hands on some ruthenium, and now you want to destroy the hard silvery-white metal of the transition series. Well, you're going to try all kinds of ways to dissolve this odd metal, but the only successful way to dissolve ruthenium is with a common household cleaner… bleach.

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

Unless you're a high-schooler building a nuclear fusion reactor, the hardest part of a science investigatory project often is coming up with a good idea. You want it to be cool yet feasible, novel but still useful.

### How To: Make a Monster Dry Ice Bubble

Sure it's been done before, but it never gets old. There's something magical about dry ice, bubbles, and especially the result you see when they're combined!

### 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: 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: 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: Use a Volumetric Flask in the Chemistry Lab

Find out how everything in a chemistry lab works, from pipettes to burners to recrystallization to storage. You'll get precise instructions on how to work and perform certain scientific duties in the chem lab, whether it's chemical or just ordinary high school science.

### How To: Make a crazy foam explosion science experiment

Check out this video to see our Fantastic Foamy Fountain in action. The experiment uses Hydrogen peroxide and dry yeast. Hydrogen peroxide is similar to water but it has an extra oxygen atom. This makes it more dangerous and only adults should handle the hydrogen peroxide.

### 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: Make fake blood from iron, chloride, and potassium

In order to make fake blood, for special effects or for Halloween, you will need the following: Potassium Thiocyanate (KSCN), Iron (III) Chloride (FeCL3), which is also known as ferric chloride or may substitute Iron Nitrate (Ferric Nitrate). You will also need water or dihydrogen monoxide.

### 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: 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: Make nitric acid

Watch this science video tutorial from Nurd Rage on how to make nitric acid. They show three ways to make nitric acid based on two different chemical approaches, both of which can be done using easily accessible materials.

### How To: Calculate Faster Than a Calculator

When you need to crunch numbers quickly — and I mean really quickly — there's a cool method you can use to multiply two numbers together in just a few seconds.

### 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: 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 area and volume of prisms

This helpful video gives simple step by step instructions on how to find area and volume of prisms. To find the area of a prism you must first find the area of the base, it may be rectangular, triangular, or otherwise. You must then multiply the area of the base times the height. Examples of all types of scenarios are given to better explain the method of finding the area. To find the volume of a triangular prism you must first find the area of the base. The next step is multiplying the area ...

### How To: Extract DNA from a Strawberry with Basic Kitchen Items

We all know that DNA is pretty amazing, but it's not something that most of us get much hands-on experience with. Even though it's in every living thing around us, we never see it, so we rarely think about it either.

### How To: Solve equations with the order of operations

In mathematics, the order of operations define the priority in which complex equations are solved. The top priority is your parenthesis, then exponents, followed by multiplication and division, and finally addition and subtraction (PEMDAS). This video tutorial demonstrates the order of operation with various examples and explains the associated methodology. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autod...

### How To: Make Black Snake Fireworks With & Without Fire

In this video, I'll be showing you how classic black snakes work and how to make them at home. There are actually two methods covered in the video — one that uses fire and one that does not. So just choose the one that fits best for your situation.

### How To: Measure the volume of a balloon

Here we will demonstrate how to measure the volume of a balloon. A balloon is not a straight edged polygon shape, usually, so the mathematical equations get that much harder, on the flip side, it may be a spherical or ovalish shape, but measurements with math alone are detrimental due to the uneven sizes of the balloon. Here is how to do it properly. You will need a bucket, preferably, to hold water, a larger container than your original bucket, and a measuring container. Place the bucket ins...

### Make Slime Without Borax: 5 Easy Recipes for Gooey Homemade Ooze

One of the only things I remember from watching Nickelodeon as a kid is the epic green slime. Looking back, I don't know what was so great about it, but every kid my age thought that being drenched in slime would be the coolest thing on earth.

### How To: Make hot ice using Sodium Acetate Trihydrate

This video in the Education category will show you how to make hot ice using Sodium Acetate Trihydrate. For this purpose you will need a pan, 100g of Sodium Acetate Trihydrate, 25ml of water, a wooden spoon and a glass. Take the Sodium Acetate Trihydrate and put 100g in the pan. Then place the pan on a stove and turn to medium heat. The Sodium Acetate Trihydrate will start to melt. In about five minutes when it has melted fully, add 25ml of water. Let the solution simmer for two minutes while...

### How To: Convert between diameter and radius

To convert between diameter and radius just follow a few steps. Sometimes we aren't given the number directly so first we need to find the diameter.

### 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.

### 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...

### 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: Turn Milk into Strong Natural Glue with Baking Soda and Vinegar

You can do all kinds of unexpected things with milk, like make your own pore strips and invisible ink, or even get rid of red wine stains with it. But did you know that you can also use it to make your own glue?

### How To: Make a Soda Can Stirling Engine

Ever wonder how to make an engine out of soda cans? Not even sure if it's possible? These videos will show you how to build a working Stirling engine out of cans and other general materials. Here it is in action: