20.309:Logistics

Safety

The chief hazards present in the 20.309 Lab come from: laser radiation, chemical and biological materials, and electric equipment. Some simple precautions will make your time in the lab much safer.

Laser safety

Laser radiation chiefly affects eyesight and skin. The lasers we will use in 20.309 are not powerful enough to do much damage to skin; however, they pose a significant risk to your vision if the beam or a reflection of it enters your eye. In 20.309, we will use three types of lasers, as detailed in the table below. Lasers are divided into classes according to their potential for causing harm.

Lab Module	Wavelength	Color	Power	Class	Safety Measures
Atomic Force Microscopy	635	Red	2 mW	IIIa	Do Not Stare Into Beam
Fluorescence Microscopy	532	Green	5 mW	IIIb	Protective Eyewear Required
Optical Trapping	975	Invisible (NIR)	175 mW	IIIb	Protective Eyewear When Beam is Exposed

Near the beginning of the term, there will be a mandatory laser safety lecture given by the Environment, Health and Safety office. More information may be found in this EHS document and in the lab manuals.

The red laser used in the AFM lab will only cause damage if you stare at it. You will sometimes view scattered light from the AFM laser through a stereo-microscope. This is safe as long as the duration is less than eight hours. Protective eyewear is not required for this lab.

The green laser used in the fluorescence microscopy lab is perhaps most dangerous type because its beam is unconstrained. The pointer can be aimed anywhere, and it might possibly emerge from an unexpected location on your apparatus as you build it. The beam is strong enough to cause permanent damage to your eyesight. Safety eyewear will be provided to you. You must wear it at all times when you or anyone else in the lab is building is using one of these lasers. Also, the blinking laser safety sign near the door must be turned any time work with these lasers is taking place. Needless to say, purposefully aiming the laser around the lab is a big no-no.

The IR laser used in the optical trap is both powerful and invisible. The power is high enough to damage your eyesight instantly. Because the beam is invisible, you may be completely unaware of its location and direction. Fortunately, the optical trap largely contains the beam. Safety goggles will be available for this lab, but are not required. Never operate an optical trap with the safety cover off. Turn on the blinking laser warning indicator any time optical traps are in use.

General Laser Safety Practices

• Always know the path of the beam.
• Keep body parts and reflective items (such as jewelry and tools) out of the beam path.
• Do not wear refective jewelry when working with a laser.
• Read the lab manual and know what special precautions must be taken.
• When in doubt, check with the lab instructor.

Lab Hours and Scheduling

The lab will be open approximately 40 hour per week. Students are responsible for scheduling sufficient time in the lab to complete assignments before the deadline. Generally, the opening hours will be:

Lab Opening Hours

Monday	10:00 AM - 6:00 PM
Tuesday	1:00 AM - 9:00 PM
Wednesday	1:00 AM - 9:00 PM
Thursday	10:00 AM - 6:00 PM
Friday	10:00 AM - 6:00 PM

You must sign up at least 24 hours before coming to the lab. Use the "LAB SIGNUP" link above in the title bar.

Please also read this Lab Guidelines Document regarding safety, lab notebooks, and other issues.

Lab attendance is mandatory. There will be no make-up labs, except in the unfortunate case of extraordinary circumstances.

Grading

• 50%: Written reports for lab modules

You will be working in pairs throughout the semester, but you will be submitting individual lab reports.

• 15%: Oral presentation

You will each give a 12 minute presentation on a selected lab module or a relevant journal paper.

• 15%: Homework assignments

These will include questions related to lecture material, lab modules, and selected journal articles.

• 10%: Lab quizzes

These are intended to help you prepare for the experiment you are performing. The questions will be straightforward and should take about 5 minutes before you begin working on each lab.

• 10%: Oral participation during lectures and laboratory modules

Your participation is essential to learning during the semester. This includes attendance at lectures and your peers' presentations.

Lab Report Grading

1. Presentation of Data (10 pts.)
   • all figures have clear purpose, have a figure number and caption, and are discussed in text
   • data plots:
     • appropriately chosen/organized (e.g. curves overlaid or compared, when appropriate, correct scales, etc.)
       
     • axes labeled with quantities/units
       
     • quality of data
   • no "data dumping" or screen captures (unless explicitly specified)
2. Analysis/discussion (10 pts.)
   • demonstrates understanding of key concepts/methods
   • coherent, logical reasoning, clear thought process
   • show key numeric parameters; include important calculations and results
   • appropriate data processing applied, described and justified
   • draw conclusions supported by the data
3. Overall quality (5 pts.)
   • report typed, well-organized, length appropriate say what you need to – not more or less
   • report requirements met
   • sufficient time spent in the lab
   • citation of any material that isn't your own (e.g. things you looked up on the web, in literature; data from others in the class; be sure to list with whom you worked on the lab)

Two examples of excellent lab reports are available here and here.