The Science of Herbs and Spices

About snow.

Winter has returned to northern parts of the world. In the northern United States, winter can mean the return of snow. Large amounts of snow fell in some American cities last month. One storm hit the East Coast, causing flight cancellations and temporarily stopping traffic in some areas.

Snow is a subject of great interest to weather experts. They sometimes have difficulty estimating where, when or how much snow will fall. One reason is that heavy amounts of snow fall in surprisingly small areas. Another reason is that a small change in temperature can mean the difference between snow and rain.

Just what is snow, anyway? Snow is a form of frozen water. It contains groups of ice particles called snow crystals. These crystals grow from water droplets in cold clouds. They usually grow around dust particles.

All snow crystals have six sides, but they grow in different shapes. The shape depends mainly on the temperature and water levels in the air.

Snow crystals grow in one of two designs – plate-like and columnar. Plate-like crystals are flat. They form when the air temperature is about fifteen degrees below zero Celsius. Columnar snow crystals look like sticks of ice. They form when the temperature is about five degrees below zero.

The shape of a snow crystal may change from one form to another as the crystal passes through levels of air with different temperatures. When melting snow-crystals or raindrops fall through very cold air, they freeze to form small particles of ice, called sleet. Groups of frozen water-droplets are called snow pellets. Under some conditions, these particles may grow larger and form solid pieces of ice, or hail. Hail can be dangerous to people, animals and property.

When snow crystals stick together, they produce snowflakes. Snowflakes come in different sizes. As many as one hundred crystals may join to form a snowflake larger than two and one-half centimeters. Under some conditions, snowflakes can form that are five centimeters long. Usually, this requires near-freezing temperatures, light winds and changing conditions in Earth’s atmosphere.

Snow contains much less water than rain. About two and one-half centimeters of rain has as much water as fifteen centimeters of wet snow. About seventy-six centimeters of dry snow equals the water in two and one-half centimeters of rain.

Much of the water the world uses comes from snow. Melting snow provides water for rivers, electric power stations and agricultural crops. Mountain snow provides up to seventy-five percent of all surface water supplies in the western United States.

Snowfall helps to protect plants and some wild animals from winter weather. Fresh snow is made largely of air trapped among the snow crystals. Because the air has trouble moving, the movement of heat is limited.

Snow also influences the movement of sound waves. When there is fresh snow on the ground, the surface of the snow takes in, or absorbs, sound waves. However, snow can become hard and flat as it grows older or if there have been strong winds. Then, the snow’s surface will help to send back sound waves. Under these conditions, sounds may seem clearer and may travel farther.

Generally, snow and ice appear white. This is because the light we see from the sun is white. Most natural materials take in some sunlight. This gives them their color. However, when light travels from air to snow, some light is sent back, or reflected. Snow crystals have many surfaces to reflect sunlight. Yet the snow does take in a little sunlight. It is this light that gives snow its white appearance.

Sometimes, snow or ice may appear to be blue. The blue light is the product of a long path through the snow or ice. Think of snow or ice as a filter. A filter is designed to reject some substances, while permitting others to pass through. In the case of snow, light makes it through if the snow is only a centimeter thick. If it is a meter or more thick, however, blue light often can be seen.

Snow falls in the Earth’s extreme North and South throughout the year. However, the heaviest snowfalls have been reported in the mountains of other areas during winter. These areas include the Alps in Italy and Switzerland, the coastal mountains of western Canada, and the Sierra Nevada and Rocky Mountains in the United States. Snow is even known to fall near the Equator, but only on the highest mountains.

Sometimes, snow comes earlier than normal. And sometimes it falls in areas that are not known for having snow. In early December, ice and heavy snow caused officials in Paris to close its main airport and the Eiffel Tower. It was the heaviest snowfall in the French capital has received in years.

Snow also fell in other parts of Europe. Scotland received its heaviest snowfall since nineteen sixty-three. A combination of snow, rain and freezing conditions caused traffic problems in Germany. There were hundreds of accidents nationwide. Hundreds of flights were cancelled, most of them at the Frankfurt airport.

Each year, the continental United States has an average of one hundred five snowstorms. An average storm produces snow for two to five days.

Almost every part of the United States has received snowfall at one time or another. Even parts of southern Florida, where many Americans go for warm-weather vacations, have reported a few snowflakes.

The national record for snowfall in a single season was set in the winter of nineteen ninety-eight to nineteen ninety-nine. Two thousand eight hundred ninety-five centimeters of snow fell at the Mount Baker Ski area in the northwestern state of Washington.

People in many areas have little or no snowfall. In 1936, a physicist from Japan produced the first man-made snow in a laboratory. Then, during the 1940s, several American scientists developed methods for making snow in other areas. Clouds with extremely cool water are mixed with man-made ice crystals, such as silver iodide and metaldehyde crystals. Sometimes, dry ice particles or liquid propane are used. Today, machines are used to produce limited amounts of snow for winter ski areas when not enough natural snow has fallen.

Snow may be beautiful, but it can be deadly. It is responsible for the deaths of hundreds of people in the United States every year. Many people die in traffic accidents on roads that are covered with snow or ice. Others die from being out in the cold, or from heart attacks caused by too much physical activity.

You may not be able to avoid living in areas where it snows often. However, you can avoid becoming a victim of snowstorms. Most people are told to stay in their homes until the storm has passed. When removing large amounts of snow, they should stop and rest often. Difficult physical activity during snow removal can cause a heart attack, especially among the elderly.

It is always a good idea to keep a lot of supplies in the home, even before winter begins. These supplies include food, medicine, clean water and extra power supplies.

Drivers have become trapped in their vehicles during a snowstorm. If this happens, people should remain in or near their car unless they see some kind of help. They should get out and clear space around the vehicle’s exhaust pipe to prevent the possibility of carbon monoxide poisoning.

Drivers should tie a bright-colored object to the top of their car to increase the chance of rescue. Inside the car, they should open a window a little for fresh air and turn on the engine for ten or fifteen minutes every hour for heat.

People living in areas where winter storms are likely should carry emergency supplies in their vehicle. These include food, emergency medical supplies and extra clothing to stay warm and dry. People in these areas should always be prepared for winter emergencies. Snow can be beautiful, but it can also be dangerous.

The Science of Herbs and Spices

People have been using herbs and spices for thousands of years. Generally, herbs come from the green leaves of plants or vegetables. Spices come from other parts of plants and trees. For example, cinnamon comes from the hard outer cover of cinnamon plants. The spice ginger comes from the part of the ginger plant that grows underground.

Some herbs and spices are valued for their taste. They help to sharpen the taste of many foods. Others are chosen for their smell. Still others were used traditionally for health reasons.

Some herbs and spices may be gaining importance in modern medicine. For example, American researchers say red pepper could help people seeking to lose weight. They say this could be especially true for people who do not usually add spices to their food.

Researchers from Purdue University reported about the effects of red pepper in the journal Physiology & Behavior. They found that small changes in diet, like adding the pepper, may reduce the desire to eat.

The spice used in the study was dried and ground cayenne red pepper. Cayenne is a chili pepper. Most chili peppers contain capsaicin -- a substance that makes chili peppers hot. Other studies have shown that capsaicin can reduce hunger and burn calories, the energy stored in food.

Over six weeks, twenty-five people of normal weight took part in the study. Thirteen of them liked spicy food. The twelve others did not. The researchers decided how much red pepper each group would receive.

One and eight-tenths grams of the pepper was given to each person who liked spicy food. The others received three-tenths of a gram.

The people who did not normally eat red pepper showed a decreased desire for food. That was especially true for fatty, salty and sweet foods.

Purdue University Professor Richard Mattes said the effect may be true only for people who do not usually eat red pepper. He said the effectiveness of the pepper may be lost if spices are normally part of a person’s diet. He said further study needs to be done. The goal is to learn how long the effect of red peppers will last and how to extend the effectiveness.

The spice turmeric comes from a tropical plant common to India. Research involving turmeric is not new. Scientists have been studying its medical possibilities for many years.

For example, researchers in Singapore completed one such study several years ago. The study was based on earlier evidence that turmeric has strong antioxidant and anti-inflammatory qualities. These qualities can help protect against damage to the body’s tissues and other injuries.

The researchers said turmeric may reduce evidence of damage in the brains of patients with Alzheimer’s disease. For this reason, the researchers designed a study that examined results from a mental-performance test of older Asian adults. The study involved curry, which contains turmeric.

The adults were sixty to ninety-three years old. None had severe memory losses. Those who sometimes ate curry did better on the tests than individuals who rarely or never ate curry. This was also true of those who ate it often or very often.

The work of the Mayo Clinic and its medical experts is world famous. In its Health Letter several years ago, the Mayo Clinic provided more evidence that herbs and spices can aid health. Its experts said spices could reduce salt use for people with health conditions like high blood pressure.

The experts said some plant chemicals are high in antioxidants. In addition to turmeric, these include cinnamon, ginger, oregano, sage and thyme.

The experts also said antioxidants like garlic, rosemary and saffron have qualities that could fight cancer. They also said limited evidence shows that cinnamon, fenugreek and turmeric may affect blood sugar levels in people with diabetes.

Cooking meat at high temperatures in the open air is a favorite activity of many Americans. But the country’s National Cancer Institute warns that this kind of meat preparation creates heterocyclic amines, also known as HCAs.

Scientists say HCAs contain substances that probably can help cause cancer. These chemicals form when amino acids react with creatine, a chemical found in muscles. Meats from organs and non-meat protein sources have little or no HCA.

Research on HCAs has made some people afraid to cook meat on a barbecue grill. On a grill, the meat heats over coals or a gas or open fire. But studies have found that adding spices to meat before cooking at high temperatures may reduce harmful chemicals. This can be done by preparing a marinade and placing it on the meat before cooking. Marinades usually contain spices and herbs added to vinegar, wine or oil. This liquid mixture also softens the meat.

Researchers from Kansas State University experimented with marinades and meat in a study published in two thousand eight. The researchers placed some steaks in already prepared marinades.

The meat then was heated for five minutes on each side at a temperature of more than two hundred degrees Celsius. The researchers also cooked steaks marinated without spices, and steaks that were not marinated. They were prepared at the same temperature as meat with the marinade mixes.

The researchers compared levels of the HCAs in all the steaks. They found that the HCAs in the meat marinated in spices had decreased up to eighty- eight percent.

Other unwanted substances, called PAHs, can be found in some meat cooked at high temperatures. The United States Centers for Disease Control and Prevention says these chemicals probably cause cancer. PAHs form when animal fat drops onto hot coals. The fat makes flames from the coals rise, leaving the PAHs on the meat.

Purdue University experts have a suggestion for preventing this. They advise people to use cooking tools that do not break the skin of the meat when turning it on the barbecue grill. And they say placing the meat in a marinade before grilling is helpful.

Herbs and spices are not used just to lessen unwanted chemical effects. They make food taste better. Some spices also destroy bacteria. Spices have long been used to keep food safe to eat. In the past, spices also helped to prevent the wasting away of dead bodies.

Herb and spice plants grow in many countries. For example, the Molucca Islands in Indonesia are famous for producing spices like cloves, nutmeg and mace. Vanilla comes from orchid plants growing in South America and other places with warm, moist weather.

Spices have influenced world history. Ancient trade routes brought spices and silk to the Mediterranean Sea area beginning more than six thousand years ago. The Goth people of Europe defeated Roman forces in battle more than sixteen centuries ago. After the fighting ended, the leader of the Goths is said to have demanded five-thousand pounds of gold and three thousand pounds of pepper.

In later years, Marco Polo and Christopher Columbus discovered new lands while seeking to extend trade with spice-growing areas in Asia. The Italian cities of Genoa and Venice became powerful because they were at the center of the spice trade. The trade was so important to national economies that rulers launched wars in their struggle to control spices.