These engines work great if you build them right. However, we stress the importance of precision. In particular, make sure the end caps and nozzle are made perfectly, otherwise you’ll have a flare.

The post New Video: How to Make Rocket Engines from Scratch appeared first on Blasted Science.

Napalm is a thick jelly made from styrofoam and gasoline that burns hot and long. It’s also terrible for the environment; don’t breathe in the dirty, black smoke unless you’re ready to die.

Previously, napalm was hidden from the general public. Only the most talented of scientists could make it. Now you can make napalm just like the pros!

The post New Video: How to Make Napalm from Gasoline and Styrofoam appeared first on Blasted Science.

This is hands-down the easiest way to make a Jacob’s Ladder, period. All you need is an old TV and a death wish.

The actual tutorial in the video is quite subtle, so here’s a written explanation of exactly what we did:

Instructions:

1. Take apart a CRT TV. Be careful! They can implode if you crack the glass.
2. Rip the circuit board out. This will probably require cutting a few wires.
3. Plug it into the wall, and turn it on. You should hear a high-pitched noise. This is the part where you be EXTREMELY careful.
4. Two of the biggest (usually red) wires will arc up to a few centimeters. These are the wires you want. Don’t get your bare skin near them. Keep your left hand behind your back at all times.
5. Hook the two arcing wires up to a pair of metal rods that are in a long V-shape. Voila! That’s all there is to it.

You might have to initiate the spark by putting something metal between the two wires at the bottom.

DO NOT TRY THIS AT HOME. A SINGLE MISTAKE WILL KILL YOU. The electricity is powerful enough to instantly kill you. Would not recommend.

The post New Video: How to Make a 20,000 Volt Jacob’s Ladder (Sort of) appeared first on Blasted Science.

How to Use Electricity is an educational series of posts designed to help teach you practical applications of electricity in DIY projects.

If you read our last post in this series, you will have read this paragraph:

Learning about electricity can be overwhelming. The purpose of this series is to explain the fundamentals of electricity in a simple and practical way. Let’s get started.

But we don’t think we did a very good job. (“We” is the word “we” use when “we” want to spread the blame.) So we’re taking a step back.

Our last tutorial was a basic introduction to a practical use of electricity, but in retrospect, that probably wasn’t the best way to begin a tutorial series. Anyone who’s ever taken a high school physics class has a fairly solid understanding of electricity. So, with that fact in mind, we’re going to pretend you’re completely clueless and are going to start with explaining electricity at its most basic.

What is Electricity?

Science aside, electricity is can be one of two things: either it charges your phone or it makes some massive sparks that will permanently ruin flint and steel for you.

There are two broad categories of electricity: static and current.

Static

Static electricity is pretty cool, but we’re not going to talk about it. Here’s a tutorial by Nighthawkinlight that explains how to make a static electricity generator.

If you clicked a link to this post because you wanted to find out what static electricity is, you’re in the wrong place. The only possible project that uses it has already been made. And you just watched it.

Current

Current electricity refers to electrons moving (as opposed to static electricity, in which electrons stay in the same place and make your hair stand up). This nifty stuff has the look, taste, and consistency of lemonade.

A lithium-ion battery

The most notable use of current electricity is made possible by the walls of your house. As you probably already knew (because you’ve read our previous post), those little, circular wall outlets are responsible for everything from mowing your lawn to spreading the butter evenly over your second helping of toast. Essentially, you owe your life to these angels in disguise. However, at Blasted Science, we don’t care about life. We are much more interested in danger. And we’ll let you play along.

Experiment

Here’s a simple, educational project you can do at home:

1. Put on half a pair of thick leather gloves.
2. In your newly insulated hand, place a piece of wire.
3. Insert one end of the wire into the left hole of the wall socket (be careful not to let the wire touch your skin. This is what the glove is for.)
4. Stick the other end of the wire into the right hole of the wall socket.
5. Try not to flinch.

What can we learn from this project?

Electricity is roughly ten times more entertaining when used incorrectly. That figure is accurate to within a factor of ten, depending on how bright the sparks get. In this example, you probably saw a fairly bright, short-lived, blue spark accompanied by a loud popping sound.

Why did the spark go away?

If too much current tries to come out of the wall outlet, the power gets shut off. Placing the wire into both holes short-circuited the wall outlet, which then tried to draw way too much current. The current flows for a fraction of a second before the fuse box snapped the puny socket’s neck, in exactly the way a murderer in rehab wouldn’t.

Why did the power in half my house just go out?

As explained above, drawing too much power will shut off the current. Often, the power to the surrounding portion of your house will also be shut off.^{[citation needed]} At least, we’re pretty sure that happens. Honestly, that might not be the case at all. We’re too lazy to test it. To fix this, locate your fuse box, open it, and flip random switches until everything is working again. Save any open documents on your computer before trying this.

Are the gloves absolutely necessary?

Technically you only need one glove. But, yes, that glove is absolutely necessary. It’s also important to note that the glove needs to be on the hand that is holding the wire. Otherwise it’s possible that you’ll feel a mildly excruciating tingly sensation that causes some serious damage to your hand. Don’t you dare do this and try to sue us! You will get hurt. We do not advise trying this. Sarcasm can’t protect you from 120 volts. Also, we don’t have any money, so that would get awkward fast.

In conclusion

Ignorance is bliss, and we aren’t going to take that away from you.

The post How to Use Electricity: The Basics appeared first on Blasted Science.

Electricity is really cool. It can also be extremely dangerous. Obviously, this shouldn’t discourage you from playing with high-powered electrical devices. It’s a good idea to know what you’re getting into, though. When is electricity dangerous?

You could just go read this PDF, but should you really trust the government with your life? Blasted Science has plenty of experience with electricity. Trust us.

How Much is Lethal?

It takes a surprisingly small amount of electricity to kill you. According to Adam Savage, all it takes is 7 milliamps for three seconds. That’s tiny. An LED would barely light up with that amount of current. And since the internal resistance of the human body is about 300 ohms, it would only require 2.1 volts to kill. That’s only slightly more than a AA battery.

Fortunately, our bodies have one big protection to electricity: skin. Dry skin has a resistance of 100,000 ohms to 600,000 ohms. You might think this means that you’d need to be shocked with at least 3430 volts before your life is at risk, but it’s not that simple.

The above calculation applies only to dry skin. Wet skin is much more conductive. Voltages as low as 50 volts can be dangerous when your skin is wet.

Breakdown Voltage

At high voltages, skin loses most of its resistance and becomes much more conductive. As eplasty.com puts it,

At 500 V or more, high resistance in the outer layer of the skin breaks down. This lowers the body’s resistance to current flow greatly. The result is an increase in the amount of current that flows with any given voltage. Areas of skin breakdown are sometimes pinhead-sized wounds that can be easily overlooked. They are often a sign that a large amount of current could enter the body. This current can be expected to result in deep tissue injury to muscles, nerves, and other structures. This is one reason why there is often significant deep tissue injury little in the way of skin burns with high-voltage injuries.

Summary

In summary, the danger of electricity is highly variable. The best option is to play it safe. Exercise caution with any moderate to high voltage source. We’ve only scratched the surface of electrical dangers. There are many other factors that are beyond the scope of this article.

Does this mean you should avoid electricity at all costs? Of course not! Just don’t be stupid. At least, not as stupid as we are. Blasted Science has made some incredibly poor decisions with electricity in the past. It’s remarkable that we’re all still alive. Please don’t follow our example.

The post How to Avoid Being Killed by Electricity appeared first on Blasted Science.