Category Archives: Chemistry/Physics

Dry Ice Can Kill You

OK, we all know that dry ice will keep things cool in your cooler, and even freeze things rock hard. You can also make that cool smoke coming out of a glass of water or maybe a centerpiece for a banquet or some such. Guess what? It can also kill you. 

It seems that at a birthday party in Moscow, they wanted to cool the pool down to take a nice bracing dip. So, they dumped some dry ice in. It cooled the water but also created a cloud over the top. Bet it looked really, well, cool.

The problem is that dry ice is the solid form of carbon dioxide (CO2). That’s the gas your body exhales through the lungs in order to get rid of it. High CO2 levels in the body are deadly. Normal ambient air is about 21% oxygen but contains only 0.04% CO2. So when the cloud of CO2 gas collected over the pool that obviously increased the level of CO2 while decreasing the level of oxygen (O2) by simple replacement. That is, each liter of air above the pool now contained a reduced amount of O2 and a greatly increased level of CO2. As the people breathed this mixture they became weak and dizzy and ultimately lost consciousness simply because they were not getting enough oxygen through their lungs to the bloodstream and ultimately to the brain. Apparently three of them died and many others were close. The take-home message is: don’t do this.

Lake Nyos

In 1986, a similar thing happened on a much larger scale at Lake Nyos in Cameroon. Some sort of geological event—-there is still controversy over exactly what happened—-created a CO2 cloud that spread across the area, killing over 1700 people. CO2 is heavier than air, so tends to hug the ground and settle in valleys and low areas. That’s what happened here. And at that Russian swimming pool.


Q&A with Expanded Audio Discussions Now on the Suspense Magazine Website

Q&A with Expanded Audio Discussions Now on the Suspense Magazine Website

Check out the new posts John Raab of Suspense Magazine and I put together. Read the Q&As and listen to the expanded discussions. Hope each proves helpful for your crime fiction.

Can DNA Be Used To Identify Multiple Assailants In a Three Decade Old Rape?

In 1863, Could An Autopsy Accurately Determine the Cause of Death?

Can My Female Character Cause Her Pregnancy To Become “Stone Baby” By Shear Will?

More to come.

Want more cool questions from crime writers? Check out my three Q&A books.

M&M 200X300

More Info and List of Included Questions


More Info and List of Included Questions

MF&F 200X320

More Info and List of Included Questions


Your Hair Dye Just Might Sink Your Perfect Crime


Hair and fibers and other trace evidence are often unknowingly left at the crime scene by the perpetrator. And those clever CSI folks can find these tidbits and analyze them. From hair, they can usually determine the species (human, cat, dog?), the color, the thickness and curliness, whether it was cut or yanked out, and other things.


But what if the hair has been altered with coloring or various chemical treatments? No problem. In fact, such alterations could add another layer of individuality to hair found at a crime scene. Using Surface-enhanced Raman Spectroscopy (SERS), dyes and chemical treatments can be analyzed and such analysis can lead to the type of treatment and even the manufacturer of the product. This could prove to be critical evidence in connecting a suspect to a crime scene.



The Writers Forensics Blog: 100 Top Websites to Bookmark

The crew over at have listed The Writers Forensics Blog as one of their Top 100 Websites to Bookmark, which they describe as a “list of great sites to present practical, real-world information on the subject.” Many great sources here.

Thanks. I’m flattered.



Surgery in Zero Gravity

How do you do surgery in zero gravity?

Very carefully. And it helps to have NASA’s latest toy.

You’ve probably seen videos of astronauts playing with water in space. No dripping or dropping here. Due to their inherent surface tension and the lack of gravity applying any external force, liquids tend to form into spheres and float around. Fun stuff.


But what about blood? Of gall bladder fluid? Or, yuck, pus from an infected wound? These are not materials you want floating around in your space capsule, or your face.

The Aqueous Immersion Surgical System (AISS) just might solve this problem. It is a saline-filled transparent box with airtight ports through which orthoscopic surgical tools can be passed.



Very clever and very cool.


Metabolic Fingerprints

Metabolomics, also called Metabonomics, is the study of the unique chemical fingerprints the metabolic processes within the body leave behind. I like the term Metabolic Fingerprint since it’s easier to say.

In medicine, metabolism simply means the array of chemical processes that silently go on within our bodies. The digestion of food, the alteration or destruction of medicines or drugs by the liver, the conversion of protein to muscle tissue, the use of various sugars for energy, the repair of injured tissues, and every other chemical process within the body would fall under the broad umbrella of metabolism.

We are a product of our genetic makeup and our environment, the two working in concert to determine virtually everything about our lives. Our genes determine how each of our metabolic processes will work. For example, an individual with diabetes metabolizes sugar and produces chemical byproducts of this metabolism much differently than does someone without diabetes.

Since each of us has a different genetic makeup and each of us is exposed to different environmental influences, including diet, medications or drugs consumed, exposure to illnesses, workplace toxin exposures, stresses, and many other things, it would be expected that each of us possesses a different metabolism and therefore a unique Metabolic Fingerprint.

The key point Is that each of us is unique genetically and environmentally, each of us has different metabolic processes going on inside, and therefore each of us produces a unique combination of chemicals and metabolic byproducts in our body. A German research team has begun using Nuclear Magnetic Resonance (NMR) Spectroscopy to develop these Metabolic Fingerprints, or as they call them Metabonomic Fingerprints.

Does Metabolic Fingerprinting have a place in current medicine and forensic science? Not yet, but maybe soon. The beauty of friction ridge prints (standard fingerprints) is that they are unique and they do not change over a lifetime. If either of these were not true, then fingerprinting would not the useful forensic tool that it is. In order for any identification technique to be useful, it must fulfill both the criteria–it is individual and it does not change over time. This is not only true in fingerprinting but also in DNA analysis.

Do our Metabolic Fingerprints fulfill these criteria? The answer is maybe. We need to know much more. With the ongoing research using NMR spectroscopy and other modalities we may soon have the answer. The problem I see is that our metabolism changes from day to day simply because each day we are exposed to different nutrients, stresses, and environmental influences. Unlike fingerprints, which are static physical properties, our metabolic properties are in constant motion. If researchers can prove that our Metabolic Fingerprint is unique and does not change over time, this could be a useful tool for forensic investigation. If the metabolic analysis of biologic materials left at a crime scene could be matched to a particular individual, when fingerprints and DNA were not available, then this could serve as a useful method for identification. DNA can often be found in latent fingerprints (the so-called touch DNA) but not always. Perhaps one day, the oils left behind in a smudged and DNA-free fingerprint will be chemically fingerprinted and matched to a particular individual. It will be interesting to watch this research and see how it develops.

Science Base Article


Caylee Anthony Autopsy Released

The autopsy report on the death of little Caylee Anthony was released this week. It is both interesting and disturbing. It showed:

No evidence of trauma–one speculation was that Caylee might have been killed by trauma, either intentional or accidental.

No drugs of any kind–another speculation was that the child might have been sedated and that the death was due to an overdose, again either accidental or intentional.

Several layers of duct tape were wrapped around Caylee’s mouth and face and it appears these might have been placed before of just after death. Could this have been to silence her? Could she have suffocated from the tape? Very disturbing thoughts.

The chemical analysis of the air in Casey’s (Caylee’s mother) car  trunk revealed 80 chemicals associated with body decomposition. In this test, air samples are taken from the trunk and subjected to various chemical analyses, the most important being chromatography, a test that can separate a chemical mixture and identify many of the components. If a decomposing corpse had been in the trunk, molecules of the gases produced would permeate the trunk carpeting. These would remain after the corpse was removed and would then be slowly released into the trunk space. Sampling and testing the air would then reveal whatever chemicals were present–in this case the chemicals associated with decomposition.

Autopsy of Caylee Marie Released: Be sure and read the autopsy and forensic reports linked to in this article. This will give you an idea of just how detailed these reports are.

Caylee Anthony: Autopsy Suggests She ‘Suffered Tremendously’


Caylee Anthony’s Mother Casey in Court


Fingerprint Chemistry: More Than Just Ridges and Patterns

In an earlier post I talked about “Touch DNA,” where DNA can be extracted from some fingerprints. The typical fingerprint is made up of oils, dirt, skin cells, and other debris that are deposited whenever someone touches a surface. The cells left behind are the source of the DNA. But fingerprints reveal much more.

A new technique developed by R. Graham Cooks of Purdue University allows for chemical analysis of fingerprints. This technique is called Desorption Electrospray Ionization or DESI, for short. DESI can reveal drugs, explosives, and other materials the person might have handled. It can even be used when fingerprints are laid down one on top of another by several different people. Each person’s print has a unique chemical make up and it is this difference that allows examiners to separate these piled up prints from one another. The usefulness of this technique in analyzing crime scene prints should be obvious.

Read more about this fascinating new tool:

DESI Gives Fingerprinting Some New Respect

Finding Evidence in Fingerprints

New Fingerprinting Technique Has Surprising Advantages

Sticky Fingers

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