The Death of Mr. Spud
Alas, you have just entered a crime scene; Mr. Spud has just been discovered BOILED!
His demise comes after an urgent plea for rescue written in black ink on a piece of filter
paper that the police have just discovered. They also picked up a suspect an hour earlier. The
suspect was carrying a black pen that Mr. Spud may have used for the note. The suspect’s
name is Olive Oyl. Olive admits to knowing Mr. Spud and says she did not like him. She
commented that she would prefer FRYING Mr. Spud to boiling him. Olive claims that Mr. Spud stole her
favorite EYE glasses and refused to return them. Sigh… sounds like matters of the heart…
Your job today as a Crime Scene Investigator is to try to prove Olive Oyl’s guilt or innocence. If she was in
police custody an hour before the discovery of Mr. Spud, could she have boiled the poor tubular? Or was the
deed done by someone else? Was the pen Olive carried the one used by Mr. Spud to write his note? Or was it a
Your report will be used as evidence in court. You will have to sign the report for it to be entered into court as
an official document. It is very important that the tests are performed correctly. So, what do you do?
Two tests. One for the time of death and the other to analyze the ink on the ransom note.
The time of death can be established by the internal temperature of the victim. As the activity begins, that
temperature will be determined using a CBL and Temperature probe at the front of the room. Mr. Spud’s
temperature at the time of his discovery is: ____________
Part I: Ink Identification – Using Paper Chromatography
In your tray you will find an ink sample taken from Mr. Spud’s note. This strip is marked with black ink. The
second piece of filter paper is blank. On the second piece of filter paper you will add a sample of ink from
Olive Oyl’s pen. This Black Pen is found in the green tray at each table
1. On the blank filter paper, draw a line of black ink along the pencil line previously drawn. Use the black
ink pen found in your tray. Retrace along the line to add a second layer of black ink. Let the strip dry for
one to two minutes.
2. Attach the two strips to the pencil in your tray by taping the blank ends to the top of the pencil. Try to
keep the level of the black lines equal.
3. Place the pencil with attached strips across the top of the beaker. Add water until the water level is ½
inch below the black lines.
CAUTION: DO NOT LET THE WATER TOUCH THE BLACK LINES WHILE POURING!
4. Allow the water to move up the filter paper, separating the component dyes in the inks. Continue with
Part II while waiting.
Part II: Time of Mr. Spud’s Demise
While waiting for the pigments to separate in the ink samples, proceed with the time analysis of Mr. Spud’s
At the time of the incident, Mr. Spud’s temperature was elevated to 100°C. Once removed from the boiling
water, his temperature started to drop to room temperature. There exists a standard set of temperature changes
for a given size and age of “potato”. Use the Program SPUD on the calculator to set up the cooling curve.
Trace along the standard cooling curve to find the time after “death” at which Mr. Spud was discovered.
1. Turn on calculator.
2. Press the PRGM key.
3. Use blue arrows on the calculator until the cursor is on the program SPUD.
4. Press ENTER.
5. The temperature cooling data was transferred to the lists from the program SPUD.
In addition, a graph of the data was established.
6. Press the GRAPH key (top row) to view Temperature Change vs. Time. Temperature (Celsius) is on
the Y-axis and time (minutes) is on the X-axis.
7. Press the TRACE key (top row) to move along the points on the graph. Notice that as the cursor moves,
values from the X and Y axes appear on the bottom of the screen.
8. Find the Y-value (temperature) which is closest to the temperature reading taken from Mr. Spud at the
beginning of the activity. Read the X value (time) from the Y value of temperature.
9. The X value indicates the time in minutes since Mr. Spud was removed from the boiling water. If the
time is under an hour, Olive Oyl could not be guilty since she has been in police custody for the past
10. Time since Mr. Spud’s demise, read from graph: _________________________
Is Olive Oyl guilty? Yes No
Has Mr. Spud been out of the water an hour? Could Olive Oyl have removed him and then tried to escape? Or
has Mr. Spud been out of “hot water” for less than an hour?
Part III: Conclusion from Ink Analysis
Examine the dye separation from the ink samples. If the black inks separate into the same bands of dyes, there
is a good chance that the note from Mr. Spud was written from the Olive Oyl’s ink pen. If the bands of color are
different, then the note from Mr. Spud was not written with Olive’s pen. What is your conclusion?
Is Olive Oyl guilty? Yes No
Your evaluation of the evidence: (write a short summary)
Signature of EXPERT WITNESS: ________________________________________________________
(If not Olive Oyl, perhaps the culprit was Ronald McDonald or that ruffian