SUCCEED

Blood Typing

Objective: Students should understand the genetics of blood types and how blood evidence can help during crime investigation

Materials: Each student will need

• Preprepared fake blood:
  • Milk combined with red and green food coloring until it looks dark red
  • Separate the "blood" into different containers labeled with the person it comes from.
• Prepared Serums:
  • Have containers labeled for Anti-A, Anti-B, and Anti-Rh serums.
  • Depending on what you would like the results of the experiment to be, fill the containers with either vinegar or water.
  • If you want a given blood to react to one of the serums, fill the container for that serum with vinegar. When you mix the vinegar and the milk, the milk will curdle.

Procedures:

Present the PowerPoint to the class.

As a class discuss the experiment they are about to conduct. Ask students questions such as the following:

• What does it mean if the blood clumps with the Anti-A serum? The blood must be either A or AB
• What does it mean if another blood sample clumps with the Anti-B serum? The blood must be either B or AB.
• What does it mean if another blood sample clumps with the Anti-Rh serum? The blood must be positive.
• How would you know if a blood sample were O-type? If the blood didn't clump with either the Anti-A or the Anti-B serums.

When the students seem to have a thorough understanding of the experiment, you can distribute the "blood samples" as well as the various serums.

• To do this, you can divide students into groups, where each student gets a blood sample from a different suspect.
• Each blood sample should have corresponding serums that will reveal its "type". For this, consider the following table where an "X" indicates that the blood clumped when combined with that serum.
  
  

  	Type A+	Type B+	Type AB+	Type O+	Type A-	Type B-	Type AB-	Type O-
  Anti-A Serum	X		X		X		X
  Anti-B Serum		X	X			X	X
  Anti-Rh Serum	X	X	X	X

Have students add a few drops of blood to each serum and observe the reaction. Record the results.

As a class discuss the findings. For example: If the blood found at the crime scene was a certain blood type. And one of the suspects has the same blood type. What could that mean?