Questions:

1) How do lasers work?

Lasers are a kind of light that is different from a light bulb and from the sun.   According to "http://wordnetweb.princeton.edu/perl/webwn?s=laser", 

S: (n) laser, optical maser (an acronym for light amplification by stimulated emission of radiation; an optical device that produces an intense monochromatic beam of coherent light))

2) What do we use them for?

According to "http://www.colorado.edu/physics/2000/lasers/index.html", Lasers are used to cut precise patterns in glass and metal, to reshape corneas to correct poor vision, and to provide intense heat in controlled fusion experiments. But we also use lasers as very precise light sources in supermarket checkout lines, CD players, and to transmit most telephone signals. 

3) Biggest/ Smallest Lasers:

The biggest laser: 

smallest laser:

A laser works by having "an electrode excites photons causing them to give off light. the light goes further back into the laser, there it is bounced off of a mirror to give it time to reach a high enough veloctity. When it gets to the other end fo the laser it hits a semi-silvered mirror which reflects half of the light back into the laser to repeat the process with other light from more photons. The rest of the light continues through the mirror and becomes the laser beam."  (wikianswers)

The biggest laser is in california and it cost 3.2 billion dollars to make.

The smallest

• Medicine - Dentistry, opthalmic and other medical uses to burn away or chemically alter tissue to excise disaffecting inclusions and speed healing.
• Industry - Cutting and welding, parts fabrication and heat treatment.
• Defense - Ranging and also painting targets for guided munitions, and countermeasures.
• Research - Interferometry and spectroscopy, super-fine cutting in the lab.
• Commercial - Printers, optical media for music, video, data and other scanning uses.
• Laser lighting - Displays for advertising and entertainment.
• Laser skin care - Hair removal, acne treatment and other dermatological uses.
• Astronomy - Determination of the "flatness" of the universe

The smallest laser in the world is smaller than a protein molecule. The gap in which the light shines through is only 5nm wide. The largest laser in the world cost $3.5 billion dollars to build, and was designed to have the energy of a nuclear explosion, with 192 beams. It is the side of a football stadium, at the Lawrence Livermore National Laboratory in California.

 Lasers are used for many different reasons. One of the main uses of lasers is for cutting flat materials. Lasers are also used for technology. Medicine lasers are used almost every day with surgeries. These lasers are much more accurate because the heat of the lasers causes thet issue around the cut to heal. In electronics lasers are used for reading bumps on the surface of a disk/c.d. When the laser hits the surface it will reflect off the disk. A detector will record where the laser is reflected, and the information is used to read information on the disk. 

This is how the laser works. 

Below is a diagram of a YAG solid state laser however the basic principle applies to all lasers.

By: Gavi, Alina annd =) =) and susan,Gavi and Alina and Alina, Susan and Gavi, and Alina, Gavi and Susan <3 <3 <3 

Objective:

Students will learn some of the properties of lasers.

Agenda:

1.  Discussion:
     Share results of pinhole camera pictures.  Show some of the samples, pass them around.  Indicate that I still need to scan these pictures.

2.  Activity:
     Safety discussion about lasers.  Indicate that one can never ever shine them into someone's eyes, and for safety we will avoid sending them towards other people if at all possible.  This is because even though the laser light is not that bright, it is concentrated more than a typical flashlight would be.  Discuss our challenge, have a laser hit all of the mirrors.

3.  Activity:
     Measuring the angle of reflection and incidence. 

Homework:

None

Objective:

Students will recognize the relationship between a vertical wave and a horizontal wave.

Agenda:

1.  Activity:
     Collect data for their labs.  They should produce a full lab report.  Students will measure the wavelength of a ruler which is moving in a wave as a result of being hit (using a piece of paper and a pen attached to the end of the rule).  Students should collect at least 5 trials for each length.

2.  Lab report:
     Write a lab report to represent your collection.

3.  Activity:
     Field trip to the dollar store.

Homework:

None
     

I was working with my partner Matt.    There were a few problems here and there.  Some of the problems were not controllable but all in all i thought that things went really well.  At the beginning we worked well with the communication and we got everything together at the right time (in class) and everything worked well.  One problem that we had was when we were taking out the photos the grade 9's walked in on us and ruined some of the pictures.  Other than that I think that it went really well.

I worked with Annie to create our pinhole camera out of a cardboard can, heavy paper, black paint, tape, a pop can, super glue, and a needle.  The process went pretty well, we were even able to make a shutter to go over the aperture. The hardest part was making the aperture just the right size. The most challenging part of this whole project was the picture taking. Since the photo paper was light-sensitive, we had to change the paper in a dark room. In my opinion, we did this more easily than others in our class, as our 'group' had less people and was generally more organized. In the dark room, we had one person replace the used paper, and one person cut and hand out the new paper. We also had to have one person make sure everyone was ready, and turn on the light. These positions differed each time we entered the room; sometimes everyone would have a part, and sometimes only one or two people would have a part. It was very quick to take the pictures, the exposure starting from 5 seconds, and supposedly increasing to 30 in intervals of 5. However, we only managed to get up to 25 seconds. When we got back inside from taking the last picture, the other group was coming out of the dark room, and apparently the Grade 10s had opened the door and turned on the light, while all the already taken pictures were out of the bag. The pictures were exposed to light, so we don't know whether or not they will turn out. I think the most difficult part of the whole process was in the dark room, considering it was, well, dark, and there were about 8 people scrambling around in the dark trying to get their pictures safe into the bag, and then trying to re-load their camera with new paper. In between all this, each pair had to write their initials and exposure time on the right side of the paper, in the dark, so at a time, many people were crowded around a single red light, passing around a single Sharpie. After this, the two stacks of paper had to be double - bagged, and the light turned on. This process repeated over and over again until lunchtime. Seeing as all the pictures we had taken had been exposed to light, I cannot yet draw a conclusion of whether or not they have been completely ruined. However, my hypothesis was that considering the size of the aperture, a 10 to 15 second exposure would be sufficient for a clear photo.

^ Our pinhole camera and Kamalaya :)

On Friday, which was when the event took place, i wasn't there. Since i didn't know what happened, i asked some other people. Other students said that they used their  pin-hole camera and went to a dark room with red lamps since the photos they were going to take would get ruined by regular light. They then cut photo paper and put it into the back of the camera. After, they would seal up the cameras and then turn on the main lights. They went outside and held the camera for 15 seconds on the object they chose for the picture. Then they went back inside, turned of the main lights, took out the paper and put it where the other ones were stored, which was a bag. 

 Pinhole camera reflection!          Omar, Tae-woo and Andrew F.

To make the pinhole camera, I had to go online, and google search how to make a basic pinhole camera. After we determined what wee needed, we split up, and we got all of the stuff that we needed to make the camera. When we got back to school to assemble our camera, it was  a new thing for me, seeing as though I had never made a camera out of cardboard and tin so I was a little confused. The spray paint we probably could have done outside to avoid all of the fumes as it was a little stuffy in the room. Some issues with the darkness in the photo room, was well, it was dark, and we had to wait for our eyes to adjust, but after the 2nd time in the room, our eyes adjusted a lot faster, and the whole process was made easier. The process was also a bit confusing in the beginning, trying to remember which envelope is which, if the completed ones go in this one, or the other. A major setback, was when, I think it was the 10’s walked in and they opened the door, while the photos were on the table! I’m not sure if they are ruined, but oh well, nobody was guarding the door! Taking the actual pictures was pretty straight forward. One of the biggest issues regards whether we actually needed the aluminium, seeing as though most other groups did not use it. Next time around, I feel that we should have some more time to prepare and build the cameras. As well, we should put more red light into the dark room.