Temperature which causes freezing
HT: io9. Sarah Zielinski is an award-winning science writer and editor. She is a contributing writer in science for Smithsonian. Ask Smithsonian A Smithsonian magazine special report.
Water crystallizes into ice at 32 degrees Fahrenheit most of the time, but not always. Probably hopefully! What is the temperature of the room?
Facilitator's Note: Changes in temperature can cause water to change state, and these changes occur at specific temperatures. For most substances, the melting and freezing points are about the same temperature. Facilitator's Note: Contrary to our instincts, the melt water's temperature will not increase as long as ice is present.
The warm room continues to add energy to the cup, but all of that energy continues to go into melting the ice rather than raising the temperature. Once all the ice has melted, that energy can begin to increase the water's temperature. Facilitator's Note: Adding salt lowers the melting point of water. Pure water and ice, kept insulated from the warm outside world, come to equilibrium over time.
On a molecular level, water molecules are freezing onto the ice at the same rate as they are melting off of it. Adding rock salt — or any substance that dissolves in water — disrupts this equilibrium. Fewer water molecules are interacting with the ice at any given moment, so the freezing rate is slowed. The salt has no effect on the melting rate, so more melting occurs than freezing — melting "wins" — and the ice melts.
In doing so, heat energy is used to break the hydrogen bonds that hold the molecules in the ice together. In other words, the ice "uses up" some warmth from the solution and the temperature drops. Melting and freezing again match rates "tie" once the temperature has dropped to the new melting point. Your health habits and lifestyle , such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.
Try Home Treatment You have answered all the questions. Try home treatment to relieve the symptoms. Call your doctor if symptoms get worse or you have any concerns for example, if symptoms are not getting better as you would expect. You may need care sooner. Pain in adults and older children Severe pain 8 to 10 : The pain is so bad that you can't stand it for more than a few hours, can't sleep, and can't do anything else except focus on the pain.
Moderate pain 5 to 7 : The pain is bad enough to disrupt your normal activities and your sleep, but you can tolerate it for hours or days. Moderate can also mean pain that comes and goes even if it's severe when it's there. Mild pain 1 to 4 : You notice the pain, but it is not bad enough to disrupt your sleep or activities. Pain in children under 3 years It can be hard to tell how much pain a baby or toddler is in.
Severe pain 8 to 10 : The pain is so bad that the baby cannot sleep, cannot get comfortable, and cries constantly no matter what you do.
The baby may kick, make fists, or grimace. Moderate pain 5 to 7 : The baby is very fussy, clings to you a lot, and may have trouble sleeping but responds when you try to comfort him or her. Mild pain 1 to 4 : The baby is a little fussy and clings to you a little but responds when you try to comfort him or her. Early symptoms of hypothermia may include: Shivering. Cold, pale, or blue-gray skin. Clumsy movements. Poor judgment and a lack of interest in or concern about what's going on.
Not speaking clearly. Cold injury to the skin may cause: Severe pain. Numbness, tingling, or a prickly feeling. Hard, stiff, shiny, or rubbery skin. Cold, pale, white, pink-purple, or blue-gray skin. Blisters or sores. Rectal temperatures are the most accurate. For example: The fingers, toes, nose, or ears may turn pale or white.
Later they may turn blue. These areas may feel numb and tingly and feel very cold to the touch. As the areas warm, they may turn red and start to throb. Symptoms of severe hypothermia may include: Stumbling and having trouble walking. Weakness, confusion, or extreme sleepiness. Slow, shallow breathing. Slow or uneven pulse. Passing out. Call Now Based on your answers, you need emergency care. Call or other emergency services now.
Seek Care Now Based on your answers, you may need care right away. Call your doctor now to discuss the symptoms and arrange for care. If you cannot reach your doctor or you don't have one, seek care in the next hour.
You do not need to call an ambulance unless: You cannot travel safely either by driving yourself or by having someone else drive you. You are in an area where heavy traffic or other problems may slow you down. Seek Care Today Based on your answers, you may need care soon. Call your doctor today to discuss the symptoms and arrange for care. If you cannot reach your doctor or you don't have one, seek care today. If it is evening, watch the symptoms and seek care in the morning.
If the symptoms get worse, seek care sooner. Make an Appointment Based on your answers, the problem may not improve without medical care. Make an appointment to see your doctor in the next 1 to 2 weeks. If appropriate, try home treatment while you are waiting for the appointment. If symptoms get worse or you have any concerns, call your doctor.
Home Treatment Most minor cold injuries will heal on their own, and home treatment is usually all that is needed to relieve your symptoms and promote healing. If you have hypothermia , try immediate first aid measures.
Stay calm, find shelter, change to dry clothes, keep moving, and drink warm fluids to prevent further heat loss and slowly rewarm yourself. If small areas of your body ears, face, nose, fingers, toes are really cold or frozen, try home treatment first aid to warm these areas and prevent further injury to skin.
Warm small areas by blowing warm air on them, tucking them inside your clothing, or putting them in warm water. Medicine you can buy without a prescription Try a nonprescription medicine to help treat your fever or pain: Acetaminophen , such as Tylenol Nonsteroidal anti-inflammatory drugs NSAIDs : Ibuprofen, such as Advil or Motrin Naproxen, such as Aleve or Naprosyn Aspirin also a nonsteroidal anti-inflammatory drug , such as Bayer or Bufferin Talk to your child's doctor before switching back and forth between doses of acetaminophen and ibuprofen.
Safety tips Be sure to follow these safety tips when you use a nonprescription medicine: Carefully read and follow all directions on the medicine bottle and box. Do not take more than the recommended dose. Do not take a medicine if you have had an allergic reaction to it in the past. If you have been told to avoid a medicine, call your doctor before you take it.
If you are or could be pregnant, do not take any medicine other than acetaminophen unless your doctor has told you to. Do not give aspirin to anyone younger than age 20 unless your doctor tells you to. Symptoms to watch for during home treatment Call your doctor if any of the following occur during home treatment: Symptoms of a skin infection develop, such as redness, swelling, or pus. Blisters develop after you begin home treatment. Symptoms have not gotten better or have gotten worse after 1 hour of rewarming treatment.
Symptoms become more severe or frequent. Prevention Many cold injuries can be prevented by protecting yourself when you are outdoors in cold weather. General tips Bring an emergency kit if you are going into the backcountry so you are prepared for cold, wet, or windy weather conditions that might arise. Head for shelter that will protect you from wind and rain if you get wet or cold. Avoid doing too much activity and sweating. Sweating increases heat loss through evaporation, so you will feel cold.
Avoid touching metal, especially with wet hands, because it will make you feel colder and may cause frostbite. Nutrition tips Eat plenty of food to help maintain your body heat. Carry high-calorie foods, such as candy bars and trail mix, when going out in cold weather.
Drink plenty of water. Carry extra water with you and drink it hourly. Your urine should be clear, not yellow or orange. If you are not urinating every 2 to 3 hours, you probably are not drinking enough fluids. Do not drink alcoholic beverages. Alcohol: Interferes with your body's ability to regulate body temperature. Affects judgment.
For example, a person may not put on more clothing when it is needed if his or her judgment is changed by alcohol. Can cause blood vessels in your skin to dilate. This increases heat loss. Reduces your ability to sense cold because it depresses the nervous system.
Do not use caffeine and do not smoke while in the cold.
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