Hot Education Posts

How To: Observe the Full Moons in 2011 (Lunar Calendar)

When's the next full moon? Every time I've looked at the moon, I've wondered if it was full. Sometimes it looked like it was, but it's really hard to tell for sure unless you know the exact date of the full moon. Seriously, there's at a couple days before and after the full moon that could easily pass as full. At least, to someone like me who isn't naturally in tune with the moon's cycle (and doesn't have perfect vision).

How To: Use a protractor to measure the height of any object

In this video, we learn how to use a protractor to measure the height of any object. First, attach a level to the protractor, followed by a straw at the 45 degree angle. Next, walk back form the object while looking through the straw. Keep walking back until you spot the top of the object through the straw, then measure to the base of the object. After this, you will have an isosceles triangle that has two equal sides. Use these sides to help find what the size of the object is. After this, a...

How To: Square expressions involving radicals

Here we look at squaring expressions that involve radicals because people tend to make some common mistakes while solving such expressions. Take 5 times the square root of y quantity squared, the answer here is not 5y. Here's the reason, square means to multiply something with itself so the square of 5 root y would be 5 root y into 5 root y. So 5 x 5 is 25 and under root y into under root y equals just y so the answer will be 25y.

How To: Find the equation of a tangent line

This is the video about how to find the equation of a tangent line. As you may recall, a line which is tangent to a curve at a point a, must have the same slope as the curve. Therefore, the slope of the tangent is m = lim f(a + h) - f(a) h-->0 h Since the slope equation of the tangent line is exactly the same as the derivative definition, an easier way to find the tangent line is to differentiate using the rules on the function f. For example, Find the slope of a line tangent to the function ...

How To: Form hydrothermal quartz

How can hot water form beautiful quartz crystals? This mine is red Georgia clay, with veins of minerals running through it. The veins are hydrothermal. Hydro means water. Thermal means heat. So the veins were caused by hot water. But how could hot water form quartz crystals?

How To: There's Metal Hiding in Your Pepto-Bismol and Here's How You Extract It

Got an upset stomach or a little heartburn? America's favorite pink pill will cure it right up. But did you know that there's actually metal hiding in those chewable Pepto-Bismol tablets? Yes, metal. Technically, it's a poor metal, but metal's metal, right? Well, we do tend to eat a lot of iron in our diets, because it carries oxygen throughout our bodies, so consuming metallic minerals isn't anything abnormal. But you'd never think that Pepto-Bismol is actually made up of metal.

News: Creepy Facial Reconstruction of Iceman Mummy

It's tough to figure out what a mummy would have looked like when he was alive; soft tissue of a human body decays, even in ice. But, Dutch brothers Adrie and Alfons Kennis took the challenge. Using techniques that belong to both science and art, they managed to reconstruct the face and body of Otzi the Iceman, a mummy who was found in the Italian Alps in 1991.

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: Focus your laser to make it burn

In this video, we learn how to focus your laser to make it burn. The best spot for a laser to burn things is at its focal point. This is where the beam from the laser is at its smallest. If you hold a match in front of the beam, it will light it on fire as soon as it's in front of it. If you put two lasers next to each other going the same direction, it won't be able to burn because the light beam is too large. If you position the lasers so the light is smaller, then they can catch something ...

How To: Use Maclaurin/Taylor series to find accurate integrals

See how to approximate a definite integral to a desired accuracy using Maclaurin/Taylor series and the alternating series estimation theorem with this free video calculus lesson. See how it's done with this free video algebra 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...

How To: Convert a decimal number into a fraction

Need to know how to convert a decimal number into a fraction in basic arithmetic? It's simple. 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). Convert a decimal number into a fraction.

How To: Clear fractions from linear equations in Algebra

Need help figuring out how to remove fractions from linear equations in algebra? 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: Properly read a decimal number

Decimal numbers are numbers which contain a integral part before a point and a decimal part after the point. The first step in solving decimal arithmetic is being able to understand decimal numbers. Reading a decimal number is similar to reading a whole number except for a few minor differences. In a normal number the right most digit is ones place and the place next to it is tens place and so on the value of the position increases as you move left. But a decimal number starts from a tenths p...

How To: Find surface area and volume of a sphere

In this how to video, you will learn how to find the volume of a sphere and surface area. Let's say you need to find the volume of a sphere with a surface area of 200 cm cubed. You will need to know the formulas for surface area and volume of a sphere. The formula for surface area is 4 pi r squared. The formula for volume is 4/3 pi r cubed. Plug in the surface area of 200 cm cubed and plug it into the formula. You should get an answer of about 3.99 cm. Now you just have to solve for the radiu...

How To: Graph linear equations using a table

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 study for that next big test). With this free video math lesson, you'll learn how to graph a system of linear equations using a T-Chart.

How To: Find a percent of a number

Having trouble figuring out percentages? If so, you'd be well served to give this free math lesson 100% of your attention. After watching it, you'll be able to answer questions like, "What's 25% of 38?" or "What's 38% of 25?" For more information on calculating percentages with simple arithmetic, watch this free video guide.

How To: Calculate percent yield

This video shows you how to calculate the percentage yield in chemistry. To find the percentage yield, you will need to divide the actual yield by the theoretical yield. Then, multiply it by 100: i.e. % yield = actual yield/theoretical yield x 100. An actual yield is the amount of a substance produced in an actual laboratory experiment. It is based on an actual physical measurement of a quantity. The theoretical yield is the yield as is calculated on paper: i.e. through calculations. Therefor...

How To: Build a DIY electromagnet for cheap

This video shows the viewer how to make an electromagnet using common items. This is done using a broken microwave, a spool, a cordless drill, a battery and a coat hanger. The microwave transformer is dismantled and the enamel insulated wire is removed. Using the cordless drill the wire is then coiled around the spool. The iron coat hanger should then be cut into small pieces and placed in the middle of the spool. It should be secured tightly. The battery was then connected to the wired coile...

How To: Factor trinomials

In this video, the instructor shows how to factor trinomials. An equation is a trinomial if it has three terms. If you factor a trinomial, you are left with two binomials which are the factors of the original trinomial. Multiplying them would result in the original trinomial. Now factor the last numerical term such that the sum or difference of those factors gives you the numerical coefficient of the middle term. Now split the middle term according to the factors obtained in the previous term...

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: Multiply rational expressions with opposite signs

In this video the instructor shows how to multiply and write rational expressions in lowest terms. The fist thing you need to do is cancel out the common factors in the numerator and the denominator. You can cancel a term in the top with a term in the bottom even if they are diagonal as long as one is in numerator and the other is in the denominator. After cancellation if you have a term in numerator and an identical term in the denominator but with opposite signs, then pull out the negative ...

How To: Find the area of triangle using fraction measurement

This video demonstrates the way to find the area of a triangle using fraction measurements. The person presenting this video first writes the actual formula for calculating the area of the triangle. The formula is: the area of the triangle denoted by ‘A’ is equal to half of ‘b’ times ‘h’ where ‘b’ and ‘h’ are the base and height of the triangle, respectively. Now, to make it into fractions, he writes ‘b’ and ‘h’ over ‘1’. Then he asks you to calculate “what is one times ‘b’ times ‘h’” which i...

How To: Simplify a quadratic formula result

In this video the tutor shows how to simplify a quadratic formula result. You can solve a quadratic equation using the quadratic formula. The first thing you have to do when given the quadratic equation is bring all the terms to one side so that you have a zero on the other side of the equals to sign. Now the formula to calculate the roots of the quadratic equation ax*x + bx + c = 0 is x = (-b + root of(b*b - 4*a*c) ) / 2 * a. The other root can be obtained by using the minus sign before the ...

How To: Find X-bar with the Z-score formula

In this video tutorial it shows you how to find the x-bar by using the Z-score formula. In the beginning of this video the formula is displayed on the right, while the values that you need to plug in are on the left. Once you plug in the values and do the cross multiplying, all you have to do is get x-bar by itself on one side of the equation. This is a simple problem on using the z-score formula to find x-bar, it can help you solve more complex problems in the future.

How To: Solve temperature subtraction problems (integers)

An educational video from free math tutoring that shows an easy way to calculate differences of temperature. Many times people commit simple mistakes in subtracting temperatures that lead to illogical results. This video explains a very common pitfall and at the same time, clears up an important concept in temperature subtraction.

How To: Calculate the area of a parallelogram

Calculating The Area Of A Parallelogram A parallelogram is a 4-sided shape formed by two pairs of parallel lines. Opposite sides are equal in length and opposite angles are equal in measure. To find the area of a parallelogram, multiply the base by the height. The formula is:

How To: Find the interior angle sum of a polygon

In this tutorial the instructor shows a method to compute the interior angle sum of a polygon. He gives us the formula for the interior angle sum of a convex polygon as (n-2) * 180 where n is the number of sides of the polygon. He goes and take a 6 sided polygon as an example and does the math by substituting the value of 'n' in the equation and arrives at the result. This video clearly gives the formula and demonstrates with an example of how to calculate the sum of interior angles of a poly...

How To: Write an argumentative research essay

Writing a research essay or an argumentative research essay can seem like a major challenge to students. All the work, all the writing all the deadlines! Simplify the entire process by learning how to gather information the correct way, namely using the resources at the school library and, more importantly, how to fill those pages. This video will show the easy way to write argumentative research essays.