Making a Speaker

Introduction:

A speaker is a device that converts an electronic signal into sound. The speaker you will build (see figure 1) consists of a Styrofoam or paper cup, a coil of wire, a permanent magnet, and a signal source. The electronic signal goes through the coil and creates a varying electromagnet. The attraction and repulsion between the electromagnet and the permanent magnet cause the cup to vibrate and produce sound.

 

Purpose:

In this laboratory, you will explore how a speaker works.

Materials:

• 1 permanent magnet
• 2 feet of wire
• 1 pencil
• tape or glue
• 1 Styrofoam or paper cup
• 1 signal source (tape player)
• 1 plug with alligator clips for tape player

Procedure:

Assemble material as shown in figure 1.

1. Leaving about 10 centimeters on the end, wrap the wire around a pencil to make a wire coil and tape or glue it to the bottom of the cup. The coil should be about 1 centimeter in diameter and contain about 15 coils.
2. Strip the insulation off the ends of the wire.
3. Place the magnet on the wire coil.
4. Connect the signal source (tape player).
5. Adjust the apparatus until you get sound coming out of your speaker.

Conclusion

1. Does the volume control on the tape player work on your speaker?
2. What kind of sound quality do you get out of your speaker? Compare the loudness and the clarity.
3. How does the sound quality compare with your string walkie talkie?
4. Explain how your speaker reproduce sound.

How to Lucid Dream?

Image via Wikipedia

Lucid dreaming is being aware of the fact that you are dreaming. This awareness can range from very faint recognition of the fact (which is often too brief and nebulous to be considered truly lucid) to something as momentous as a broadening of awareness beyond what has ever been experienced even in waking life. What a dreamer does with lucidity reflects personal tendencies and levels of skill attained usually through experience and practice. Although a lucid dreamer can influence the dream’s structure, characters, course, etc., it is not a given that a lucid dream is about what the dreamer wants it to be about. Seasoned lucid dreamers who are more often lucid than not will continue to encounter psychological and developmental challenges in the dreamscape. The agreeable and the distressing, the easy and difficult, beautiful and horrifying, are all occasioned much as they are in regular dreaming. But whereas a regular dream is filled with the convoluted subtleties of the subconscious mind enumerating its issues before a largely unconscious dreamer, a lucid dreamer has the opportunity to consciously explore at any level.

Gaming Technology Helps India Prepare For Terrorist Attacks

This 3D model of Bangalore’s Garuda Mall would be right at home in a modern video game, but it’s much more than that. It’s part of a simulation aimed at helping emergency response teams deal with the all-too-real possibility of a terrorist attack.

Terrorism is a major issue in India. Over the past year alone the country has seen multiple devastating incidents, from the February explosion at a German Bakery in Pune that left 14 dead and more than 60 wounded, to the December bombing in Varanasi that killed a toddler and saw more than 20 injured in the stampede that followed. Fighting terrorism is a key national priority in India.

How to Crack the Account Password on Any Operating System

Computer passwords are like locks on doors – they keep honest people honest. If someone wishes to gain access to your laptop or computer, a simple login password will not stop them. Most computer users do not realize how simple it is to access the login password for a computer, and end up leaving vulnerable data on their computer, unencrypted and easy to access.

Are you curious how easy it is for someone to gain access to your computer? If so, read on to see the technique one might use to figure out your computer password.

How to Calculate 1 Year On Earth

I’m gonna ask you a quick question: How do you calculate that 1 year has passed on Earth? The answer may seem simple enough, but it is not. The problem is that our planet does not return to its starting point once it was gone all the way around the sun, so how do you know when a year starts and when it ends? Check out this interesting video to find out.

Secret Codes You Aren’t Meant To Know

The use of codes is intended to convey essential information quickly and with a minimum of misunderstanding to staff. Some places use secret codes to pass information between store employees. These are meant to be a secret as they don’t want to alarm the non-staff members or alert someone like a thief to the fact that they have been noticed.

Name Codes

Code Oscar: On a ship, a code oscar means someone has gone overboard. If the ship has to maneuver erratically to handle the situation, it must also send out blasts on the signal so that other ships nearby are aware of the fact that it is about to change its course. It should be noted that ships don’t have an internationally standardized set of PA signals and they can differ from place to place, but this is a fairly commonly used one.

NHTSA to update 5-star testing process

The NHTSA is set to debut a new testing procedure for the 2011 model year. The regiment will make it more difficult for new cars and trucks to earn the five-star safety rating.

What if we lived on the moon?

No one lives on the moon…yet.

Anyone who grew up with the Apollo moon launches in the 1970s, along with the movie “2001: A Space Odyssey“ (which premiered in 1968), was left with the impression that there would be c­olonies on the moon any day now. Given that it’s now more than 30 years later and there’s been no significant progress, it’s safe to assume there won’t be a moon colony any time soon. But it’s still a tantalizing thought. Wouldn’t it be cool to be able to live, vacation and work on the moon?

Let’s say we did want to colonize the moon. There are some basic needs that the moon colonists would have to take care of if this were any sort of long-term living arrangement. The most basic fundamentals include:

• Breathable air
• Water
• Food
• Pressurized shelter
• Power

Can you really laser proof anything?

Last week, Major Lazer and La Roux joined forces to release their “Lazerproof” mixtape, a mash-up of tracks from their respective 2009 debut albums. The title ” is a take on La Roux’s hit single, “Bullet Proof,” and in addition to providing a sweet 50 minutes of electro, dub and hip-hop goodness, it also raises the question: “Hey, can something really be laser proofed?”

The U.S. Air Force thinks so, which is why it put out a 2008 request for project proposals to protect future soldiers and weapons against the looming proliferation of laser weapons. The proposal called for the following:

Laser Eye Protection (LEP) Technology:
This technology has actually been available since 1999. Essentially, pilots wear protective goggles treated with a special dye to protect against near lasers. Lasers, remember, are just Light Amplification by Stimulated Emission of Radiation. These visors protect aircrews from laser hazards associated with their own infrared-based targeting systems, as well as hostile lasers.

How McDonald’s Works

It’s not a commonplace thing to visit a sanctum sanctorum – McDonald’s fast-food restaurant. Almost every one of us visits it at least a few times a months, and some of us even more often; but have they ever thought of how all these burgers are made? Want to find out? You are welcomed inside.