How does it matter? Measure the Spatter!

by Rondell Bob

Background Research!

• Smooth surfaces reveal fewer spatters because there is less surface area to deflect the liquid.

• The higher the energy of the impact, the smaller the drops are.

• You can figure out the point of origin above or away from the surface by using a spatter program.

Background Research Continued!

• To figure out the bloodstain or water pattern you need to determine some of the following: Movement and direction of persons or objects while they were shedding blood, position of persons or objects during bloodshed, movement of persons or objects after bloodshed.

Introduction

• The purpose of this science project is to learn more about the field of forensic science by performing balloon spatter experiments to see how blood would spatter from a body hitting the ground.

• Water balloons are a great source for comparing what would happen if a body hits the ground causing blood to spatter.

• My hypothesis is that the higher you are from the ground the rounder the impact size will be.

Procedures!

1. Fill 10 water balloons with the same amount of water. Use a scale to confirm that the water balloons all weigh the same amount, plus or minus 10 percent. For example, if your first balloon weighs 5 ounces (oz) then the rest of the balloons should weigh between 4.5 and 5.5 oz.

2. Find a location that has a large, clean concrete area with steps that you can climb for different heights. Or you can use a ladder on a large clean concrete area. If you use a ladder, make sure that you have someone holding the ladder for safety.

3. Start by standing on the ground. Have your helper hand you a water-filled balloon. Hold the balloon straight out in front of you.

Procedures Cont.

    4. Now have your helper measure the distance of the balloon from the ground with the tape measure. Have your helper record this data in your lab notebook, using a data table similar to the one below.    5. Have your helper use the stopwatch to time how long it takes for the balloon to fall and                              spatter. Release the balloon and observe the spatter that it makes on the concrete. Note the time in your lab notebook. If the balloon doesn't break at this distance go to step 7 and increase your starting distance.

    6.  Calculate the speed, or velocity, of the balloon. Write the value down in your lab notebook.

Procedures Cont.

        7.    Repeat step 5 two more times. Note the data in your lab notebook.   8.    Increase your distance from the ground and then repeat steps 5 and 6. Increase the distance at least two times beyond the starting distance. There should be three trials for each distance. Record all data in your lab notebook. Each time that you step up a stair, have your helper measure the height of that one stair. Add the height of the stair to the previous distance of the balloon from the ground to calculate the new distance of the balloon from the ground. 

Materials

• Water balloons, which are different from regular party balloons (10)• Digital kitchen scale • Ladder (optional) • Large clean concrete area • Measuring tape • Stopwatch • Helper 

 Distance of Balloon from ground

Trial Falling Time Velocity Spatter Observation

Distance 1: 1. 

2. 

3.

.4 seconds

.4 seconds

.4 seconds

5.5 feet/.4seconds for all of the trials

Distance between initial impact and outermost spatter=  35 inches for all

Distance 2: 1. 

2.

3. 

.5 seconds

.5 seconds

.5 seconds

6.25 feet/.5 seconds

Distance between initial impact and outermost spatter= 51.5 inches for trials 1 and 2. 51.3 inches for trial 3

Conclusion!

My hypothesis was correct and the farther up you are from the ground the rounder and bigger the impact size seems to get. When you vary the water balloons’ weight and drop it from the same height, the greater amount in the water balloon the bigger the impact size. 

 

 

Bibliography• Wikipedia Contributors. Forensic science. Wikipedia: The Free Encyclopedia. Retrieved   

November 13, 2011 from http://en.wikipedia.org/w/index.php?title=Forensic_science&oldid=212886781

• TPT. (2006). Forensics by Kalia and Carolyn. DragonflyTV, Twin Cities Public      Television. Retrieved November 13, 2011          fromhttp://pbskids.org/dragonflytv/show/forensics.html

• Wikipedia Contributors. (2008). Bloodstain pattern analysis. Wikipedia: The Free              Encyclopedia. Retrieved November 13, 2011    from http://en.wikipedia.org/w/index.php?title=Bloodstain_pattern_analysis&oldid=2071 62335   

• Layton, Julia. (2008). How Crime Scene Investigation Works. Howstuffworks. Retrieved   November 13, 2011 from http://science.howstuffworks.com/csi.htm

• American Academy of Forensic Sciences. (2008). Resources—Choosing a Career: So You Want   to Be a Forensic Scientist! Retrieved November 13, 2011 from            http://www.aafs.org/choosing-career

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