OBSERVING THE EFFECTS OF SOLAR UV RADIATION ON CELLS - Each person creates their own report!

Big Idea:  UV is a high energy light frequency

Background Information: Use information from your research and your notes that you think are the most pertinent for your background information. Include information about the product or material you will test, mutant sunsensitive yeast, what is UV light (UVA, UVB, UVC) , how does it affect DNA, why is it beneficial to humans, why are some people more vulnerable to sun damage, etc. Be sure to include the source for each piece of information.

Research Question:  What can you test about a sun protectant produce?

Hypothesis: What do you think will happen, why?

Safety:  Follow aseptic technique.  Wash tables and hands before and after handling slants and plates.  Wear goggles when preparing petri dishes with yeast. Do not look directly into the sun when positioning your plates.

Experimental Design: Complete all parts of experimental design. Include the steps in the procedures below.

Include the materials list in your experimental design

tube containing mutant yeast 2 YED petri dishes/ table

Sterile pipette

Sterile Q-tips for spreading yeast Materials you will use to test product

Procedures:

____1. Remove books, all other materials from tables, tie back hair.

____2. Disinfect table and wash hands.

____3. Swirl your stock tube that contains the mutant yeast solution.

____4. Use the sterile pipette to drop 10 drops of the yeast/water solution all over the YED Petri dish. Use the clam shell technique when you open the Petri dish to prevent contamination.  

____5. Use a sterile Q-tip to gently spread the yeast solution all over the plate.  

____6. Cover the dish with dark paper while you repeat finish the procedures.

____7.  Repeat steps 2-6 to make a second plate if you need this for a control.

____8. You are now ready to set up the plates for your UV experiment. Keep them covered until you are ready to expose them to sunlight.

____9. Generally exposures will be between 5-7 minutes.  Note the start and finish time to find out exposure time. Also note conditions, such as sunny, cloudy etc.  Set out the plates so that they face directly into the sun.  You can check this by holding plates to minimize shadows.

____10. After exposure, wrap plates in aluminum foil, and label.  They will incubate overnight in the incubator.

Data:  Make a table to record data and draw a picture of your petri dishes

Description of Results:  Describe your data in graphs or picture form.

Conclusions:  

Follow conclusions protocol in notebook

Constraints and Limitations: One for each category

1. Conditions of experimental system that could lead to error: why is this not exactly like your skin?
2. Conditions of experimental procedures that could lead to error.

Next Research Question:

Self Evaluation:  Must be complete for a grade! If your evaluation is not accurate, one full grade will be subtracted from your score.

____  Research Question is logical and contains both independent and dependent variables ( 0-2 pt)

____  Background information contains at least 5 pieces of information from notes and additional sources ( 0-5 pts)

____  Hypothesis relates to problem and is stated in the if, then, because format ( 0-3 pts)

____  Safety is clearly stated, and all procedures followed (0-1 pt)

____ Steps for your experiment are clearly written in a way that someone else could set up your experiment, including a picture of your set-up (0-5 pts)

____ Experimental Controls are listed (0-5 pts)

____ Data is accurately recorded in a neat chart or drawing (0-2 pts)

____ Description of actual results clearly summarizes information contained in data chart (0-1 pts).

____ All four portions of conclusions are complete.  Response to hypothesis, data, compare data,  how it relates to background information (0-5 pts)

____ Limitations are thoughtful and complete (0-2 pts)

____ Next Research question contains both an independent and dependent variable. (0-1 pts)

____ Report is word processed and neatly organized. (0-5 pts)