Alien Discovery Version

Part 1 (Page 2)

1a	1 pt	Orange, Golden-orange
1b	1 pt	5
1c	1 pt	Acid

Part 2 (Page 3)

2a	1 pt note: Blue, Dark blue, Blue-green are not acceptable.	Green, Dark green
2b	1 pt	9
2c	1 pt	B (too basic)

Part 3 (Pages 4 and 5. Score questions 3a and 3b together.)

1. Medicines tested (Meds)

   3 pts- 1 pt for each medicine tested, either separately or against blood. (There must be some indication of testing; e.g., give no points for the letter A alone with nothing in the results column.) It is OK to include Solution X in these tests if it is included in all three tests.
   1 pt- medicines tested against blood (Bonus point).

   Note: It's OK if the student made other tests besides the ones for which he/she is awarded points.

2. Drops of medicine and blood (Drops)

   1 pt- Recorded number of drops of medicine used. Needs to record for at least two medicines or for the same medicine two different times. It is OK to say "repeat the same steps for Medicines B and C."

   1 pt- Constant amount of blood used in comparing the medicines. Needs to use same amount in testing all 3 medicines independently before experimenting with different amounts. (Award point if student dips all strips into blood first and then drops medicines on blood-soaked strips if they say "dip strips to the same depth" or other instruction to indicate constant saturation.) Award point if amount is given for one test, and then student says something like, "repeat the same steps for medicines B and C."

   1 pt- Constant number of drops of medicine added to the blood. Needs to use same amount in testing all 3 medicines independently before experimenting with different amounts. No points if medicines are not tested against blood. Award point if amount is given for one test, and then student says something like, "repeat the same steps for medicines B and C."

   Note: If student tested only Medicine C plus blood and reached the right (neutral) solution and recorded the number of drops of both substances accurately, award 2 pts total for Drops.

3. Accuracy of results (Result)

   3 pts- 1 pt for each correct pH or color reported. Maximum of 3 points.
   
   

   Medicines only:	A	10-11 Base	Blue, Purple
   	B	6-8 Neutral	Greenish Yellow, Yellow
   	C	1-3 Acid	Pink, Rust Brown, Red
   With Blood:	A	10-11 Base	Blue, Purple
   	B	9 Base	Green, Dark Green
   	C	1-8 Neutral, Acid	Light Green, Yellow, Golden-Orange, Pink, Rust Brown, Red

   
   
   Note: If students lists two sets of results (e.g., one for medicines alone and one for medicines plus blood), award points for whichever set has higher score. If student lists three sets of results, award points for medicines for which at least two of the three results are correct.

4. Procedures (Proc)

   1 pt- Uses clean cup, if mentioned at least once, or uses multiple cups.
   Note: "Use separate cups" or "put in each cup" or "per cup" also acceptable.

   1 pt- Use new pH strip, if mentioned at least once.

   1 pt- Swirl solution in cup, if mentioned at least once. (Also award point for "stir," "mix," and other synonyms.)

5. Conclusion (Con)

   1 pt- Tells when to stop, explains goal, or states a conclusion. E.g. "Stop when you get a yellow color," "Medicine C is better - we have found a cure." The statement does not have to be correct, just a goal or a conclusion.

PART 4: (Page 6)

4a	1 pt- Medicine C Note: 4a is a gateway point for 4b. Award no points for 4b if 4a is incorrect. Also, since students using small amounts of alien blood may have found that C was too strong, thus attempted to dilute its strength, a combination of A and C, or B and C is acceptable. However, to award the point for a combination of medicines, the answer must agree with the results of part 3a & b. [We did not use the rule in italics in scoring 8/94, but it is a good rule and should be a part of the final rubric.]
4b	1 pt- C (or the combination) brings the blood back to normal or neutral or pH of 7. 1 pt- Mentions 1 or more of the following: C (or C+A; C+B) is acidic and the blood is too basic. C (or C+A; C+B) lowers the pH of the blood. Medicine A made the blood more basic and B had no effect. Note: Award no points for 4b if the student states that medicine C (or the combination) itself is closer to neutral; the correct answer is that C can neutralize the blood.
4c	1 pt- By adding any one of the following or any combination of them (a combination can include Medicine B as well): "Adding an acid and a base" is wrong. An acid Solution X Medicine C
4d	1 pt- By adding either of the following or a combination of them (a combination can include Medicine B as well): a base Medicine A

Part 5 (Page 7)

5a	1 pt - Fish stopped dying because Pro-Base made the pond less acidic, returned the pH to neutral, or balanced the water. 1 pt- Fish began dying again because additional Pro-Base made the pond water too basic, or the pH went past neutral to make the pond basic. Note: Answers which make no reference to "base" or "neutral" or pH - e.g., "They gave it too much," or "They need to give it less," or "It was too strong," or "They gave it the right amount" - are not acceptable.
5b	1 pt - B (Add an acidic substance)
5c	1 pt - The acid is needed to bring the water from a base back to neutral pH, e.g. "It brings it back to neutral," "To reverse the process," or "Balance the water," is also an acceptable answer. 1 pt - But stop adding acid when the water has become neutral. The response must provide enough information to tell how to proceed correctly, e.g., what amount is needed to get to neutral, or what actions would disrupt neutrality.