How To: Make Your Own Homemade Glow Sticks

The first glow sticks were patented by the US Navy in the 70s, but back then, they were called "Chemiluminescent Signal Devices." Today, glow sticks are still used by the military, emergency services, campers, divers and, of course, ravers. I may be done with the glow-in-the-dark parties from my college days, but I still think glow sticks are pretty legit, and always thought it would be awesome to make some for myself. Talk about a cool application for all those boring chemistry lectures.

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: 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 Be Your Own SpaceX: Design, Build & Test Liquid-Fueled Rocket Engines

Move over NASA— SpaceX is taking over. Well, not really. But today, the privately funded spacecraft company broke all expectations when their Dragon capsule fell to a soft landing in the Pacific Ocean, completing an undoubtedly successful demo flight of nearly two full trips around Earth. It was the first re-entry of a commercial spacecraft ever, bringing commercial space transportation closer to reality.

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. Of course, the first thing I did was beg my parents to buy me some fake slime, but I never knew I could've easily made my own at home. One of the most common ways to make slime is to combine liquid glue with water and a household chemical called borax. ...

How To: Find the opposite and absolute value of a number

View the absolute value of a number as its distance from zero. When you take the absolute value of a number, you always end up with a positive number (or zero). Whether the input was positive or negative (or zero), the output is always positive (or zero). For instance, | 3 | = 3, and | _3 | = 3 also. This property that both the positive and the negative become positive makes solving absolute-value equations a little tricky. But once you learn the "trick", they're not so bad. Let's start with ...

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: 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: Solve basic percentages

In this video tutorial, viewers learn how to work out basic percentages. The key is to always find 10% of the number first. To find 10%, divide the number by 10. It's very simple because you simply move one decimal to the left. Once you have found the 10%, you can simply find the next 10% by doubling the number. The other thing you can do is find 5% of the number by dividing the 10% number in half. This video will benefit those viewers who have trouble with find percentage or forgot how to an...

How To: Remember "greater than" & "less than" symbols

This video shows you how to easily remember "greater than" and "less than" math symbols. The first thing you have to remember is that "less than" symbol looks like the letter L ("less than" symbol is "<"). When you see this sign, remember that < looks like L and means "less than". The other symbol, "greater than" does not look like the letter L, therefore it cannot be "less than" and it's easier to remember. The "greater than" symbol is ">". That's it! Good Luck!

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: 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: Find a missing coordinate given: coordinate & equation

In this video, the instructor shows how to find an unknown coordinate given the other coordinate of that point and the equation that passes thought the point. A point is said to lie on the graph, if the point can satisfy that equation of the line. To check if a particular point satisfies an equation, all you have to do is substitute the value of the point in that equation and check if it validates the equation. Now, substitute the given point with an unknown coordinate in that equation. If th...

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: 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: Build a catapult out of rubber bands & a wire hanger

In this tutorial, we learn how to build a catapult out of rubber bands & a wire hanger. To do this, you will first need: one wire hanger, plastic spoon, rubber bands, small marshmallows, and measuring tape. Now, hold your hand in the center of the hanger and pull up both sides around it. After this, fold back the front for balance and straighten it up so it's stable. Next, you will take one rubber band and put it around the sides. Then, take the spoon and put it in between the rubber band and...

How To: Find a percentage of a whole number in basic math

Need help figuring out how to find a given percentage of a whole number (e.g., 16% of 736)? Watch 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). With this free math tutorial, you'll learn how to find percentage values in basic arit...

How To: Evaluate square roots

This is the video about how to evaluate square roots. The square root of a number is a number that you can square to get it, that is, a number that you can multiply by itself to get the number. So, 2 is a square root of 4, because 2 x 2 = 4, and 3 is a square root of 9, because 3 x 2 = 9. (-2) x 2 is also 4 and (-3) x 2 is also 9. Numbers that have square roots always have two, a positive one and a negative one, but the square root symbol means only the positive one, so we can have one answer...

How To: Prove the log a + log b = log ab logarithm property

See how to prove the log a + log b = log ab logarithmic property with this free video math 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). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll...

How To: Multiply decimals together

In this tutorial we learn how to multiply decimals together. Start off by ignoring the decimal points on the equation and just imagining you have normal numbers. Then, multiply the two numbers that you wrote down together. Once you figure that out, it will be time to reintroduce the decimals. Look at the place the decimal is in each number in the beginning equation. Then, add the decimal places together between each of them. From here, place the decimal on the end of the answer you came up wi...

How To: Use a Peltier module to create free electricity from heat

A Peltier module allows you to turn heat into electricity. Because you can place it in areas that are normally warm anyway, the electricity created is "free" in a sense, though it does work best when one side of the module is cold and the other is hot. In other words, all you'll need for this project is the Peltier module and a cooler surface such as soil or water, and a warm area such as a well lit window or warm pan.

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