This is an example of a Rubric. A Rubric is an alternative assessment used to evaluate and assign grades to students doing types of lessons that would otherwise be difficult to evaluate. Hands-on lab activities are a good example of something that can be evaluated with a Rubric. You should explain the system to the students before the activity and explain that scores of 2 or below are very rare. Point out to them that no matter what the level, they are expected to participate in the activities and follow all steps in the procedures as well as behave in a mature manner and follow all safety procedures.
4 points (equivalent to 100 percent) Student participates in all activities, following each and every step in the "Procedures" section.  Student answered all questions (most correctly).  Student met all expected outcomes from the lab.  Student correctly did any chart or graph.  Student behaved in a mature manner and followed all Safety Procedures.
3 points (equivalent to 80 percent) Student participates in all activities, following each and every step in the "Procedures" section.  Student answered all questions (many correctly).  Student met most expected outcomes from the lab.  Student attempted to do any chart or graph.  Student behaved in a mature manner and followed all Safety Procedures.
2 points (equivalent to 60 percent) Student participates in all activities, following each and every step in the "Procedures" section.  Student answered most questions (many correctly).  Student met some expected outcomes from the lab.  Student attempted to do any chart or graph.  Student behaved in a mature manner and followed all Safety Procedures.
1 point (equivalent to 25 percent) Student participates in all activities, following each and every step in the "Procedures" section.  Student answered some questions (many correctly).  Student met few expected outcomes from the lab.  Student unable to do any chart or graph.  Student behaved in a mature manner and followed all Safety Procedures.
0 points (equivalent to 0 percent) Student failed participates in activities, did not follow most steps in the "Procedures" section.  Student did not answer questions.  Student met no expected outcomes from the lab.  Student did not try to do any chart or graph.  Student behaved in an immature manner and was a Safety Hazard..

    A note about using Rubrics and "Authentic Assessment".   Keeping this Rubric in mind as you observe your students in action gives you a quick and easy method of evaluating their work.  With properly trained students, you can quickly eliminate all but the top two stages.  Instead of using a rating of from zero to four points, I like to assign percentages.  For three points, I assign 83 percent, the maximum value of a C in my county.  For two points, I assign a value of 63 points, the maximum value of an F in my county.  Of course, you are free to assign your own values to this Rubric if you decide to use it.