You can use a simple cat toy (laser pointer) to demonstrate the Tyndall effect. “The Tyndall effect, also known as Tyndall scattering,” according to Wikipedia, “is light scattering by particles in a colloid or particles in a fine suspension.” You can use the laser to test three different mixtures: colloids, suspensions, and solutions. I’ll demonstrate Tyndall scattering in a colloid (milk), in a suspension (dirt), and a solution (sugar) with a cat toy (Laser pointer).

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Norwegian women who choose to have children often say goodbye to their careers. Men, on the other hand, tarry on. Norway has, since the 1800s, come a long way towards a more egalitarian society, but when a child enters the relationship between a woman and a man the consequences for the woman are different to those for the man, according to the thesis of Eirin Pedersen at the Department of Sociology and Human Geography at University of Oslo.

The connections between technology, urban trading, and international economics which have come to define modern living are nothing new.

Back in the first millennium AD, the Vikings were expert at exploring these very issues.

Less efficiency sounds bad, in the modern world of optimization, where everyone wants to sell you a 10-minute workout that maximizes your time.  But in the ancient world of evolution, you need to turn the tables.

Due to the boom-and-bust nature of existence prior to the last 50 years, we have evolved protection against starvation - our bodies adjust on the fly. That is why if you just go on a crash diet, you will lose some weight right away and then plateau and if you eat normally again, the weight comes back. Your body 'settles in for a long winter' and metabolic efficiency goes up.

Why did the first human populations migrate out of Africa? It is the biggest debate in anthropology but no one can be sure of the answer. When it happened can at least be an informed debate and two hypotheses dominate the cultural landscape - but they both involve a common denominator that might shed light on why.

One popular belief is that human populations expanded rapidly from Africa to southern Asia via the coastlines of Arabia 50,000 or 60,000 years ago while another is that dispersal into the Arabian interior began 75,000 or even up to 130,000 years ago, but during multiple smaller phases as increased rainfall provided sufficient freshwater to support expanding populations.

Both involve climate change. 

Cells lining the intestinal tract form a critical barrier, protecting our bodies from the billions of bacteria living in the gut. Breaches in this barrier are driven largely by a single signaling molecule called tumor necrosis factor (TNF), elevated amounts of which are associated with inflammatory bowel diseases like Crohn's disease and ulcerative colitis.

Governments and taxpayers deserve to know that their money is being spent on something worthwhile to society. Individuals and groups who are making the greatest contribution to science and to the community deserve to be recognized.

For these reasons, all research has to be assessed. Judging the importance of research is often done by looking at the number of citations a piece of research receives after it has been published.

Patients who increased doses of opioid medicines to manage chronic pain were more likely to experience an increase in depression, according a new paper in Pain which expands findings in a previous study of Veterans Administration (VA) patients.

Jeffrey Scherrer, Ph.D., associate professor for family and community medicine at Saint Louis University, and his colleagues studied questionnaires from 355 patients from nine practices in the Residency Research Network of Texas who reported chronic low back pain initially and at one-year and two-year follow ups. The respondents to the survey were 72.4 percent female, older than 46 (75.2 percent) and mostly of Hispanic or African-American descent (57.5 percent).

Contrary to claims by proponents, only a minimal amount of heavy metals are removed in the hookah 'filtration' process.

On average, only 3% of heavy metals present in tobacco are removed and this would not be enough to protect users from exposure to the toxins. 

Shisha smokers claim that a hookah is less damaging than cigarette smoking due to 'filtering' by bubbling through water but a typical hookah smoking session can expose someone to 100-200 times the volume of smoke in a single cigarette.