Best Answer

Instant hot and cold packs are used by athletes to quickly and conveniently treat an injury. They last for about 20 minutes. The packs take advantage of chemicals that either absorb a lot of heat or release a lot of heat when dissolved in water. When a chemical process absorbs a lot of heat it is called endothermic. When heat is released, it is called exothermic.

In cold packs, ammonium nitrate is used because it absorbs a lot of heat when it dissolves in water. The water and ammonium nitrate are in separate compartments in the pack. When the cold pack is needed, the chambers are broken and the ammonium nitrate dissolves in the water, absorbing heat and making the pack as cold as 0C.

In hot packs, calcium chloride or magnesium sulphate are used, along with the water. They release heat when the chambers are broken and the chemical dissolves in the water. A hot pack can reach a temperature of 90C.


User Avatar

Wiki User

โˆ™ 2016-10-04 10:54:41
This answer is:
User Avatar
Study guides
See all Study Guides
Create a Study Guide

Add your answer:

Earn +20 pts
Q: How do cold packs work?
Write your answer...
Related questions

Who invented cold packs?

Cold packs were invented 25 years ago by Cardinal Health.

What are some uses for cold packs?

Cold packs work so well for alleviating pain from swollen muscles and aching joints. They are also used on minor burns to keep them from damaging skin too much.

How are Cold packs used?

Cold packs and ice bags are placed on a localized site and provide topical relief

Why do cold packs feel cold?

ammonium nitrate

Why do ice packs get so cold?

the ammonium nitrate used in most common ice packs retains cold temperatures

Do dogs work in packs?

Dogs, known to be "A Man's Best Friend" only work in packs in the wild. Canines can also work in packs if they are pets, but it is way less likely to work in packs more than wild ones. So, in the conclusion, the answer is: Yes, wild dogs work in packs.

Is there chemical reactions in hot and cold packs?

Yes, hot packs have exothermic reactions (the contents create heat) and cold packs have endothermic reactions (they require heat to occur, therefore making the surroundings colder). In hot packs its a reaction between water and a salt solution, and in cold packs its normally water and ammonium nitrate. peeace

What keeps lunch cold?

Ice packs keeps lunches cold.

Can you recycle cold packs?

if you can see the lable for it then it is

How to heal bruising?

Cold packs and time

Do cold packs absorb energy?

No, they release energy.

Should back pain be treated with cold or heat?

Cold packs are recommended within the first 48 hours after back pain begins, with use of hot packs subsequently.

What are some retailers that sell cold packs?

Cold packs can be purchased at most big box stores such as Walmart or Target in their first aid section. They are commonly known as ice packs where one can either break the bag to make instant cold to treat injuries or they can be shaken to create the same effect.

What are cold packs?

Cold packs are a category of therapeutic applications that are used deliver a comfortable and prolonged exposure to cold to a specific and isolated area of the body when in pain or injured. When a cold pack is used this way it is helpful in reducing pain and reducing inflammation. Cold packs are normally made with ice inside a closed container, or the newer form of a gel material that can be reused by placing in a freezer.

Why wont your texture packs work?

Your texture packs may not work because you are using the incorrect version, so you will need to apply a patch to make them work.

What are hot and cold packs for?

soothing joint and muscle aches

What helps bad backs?

streching or cold then hot packs

Do unused cold packs expire?

In short yes they do expire. The timing varies depending on the manufacturer. If the pack appears yellow in color most likely it will not work to its original standards. It may not get as cold or may not stay cold for as long. The further from white the color is the less it is going to work properly.

Do Walgreen's cold pack contain ammoniun nitrate?

is there ammonium nitrate found in walgreens cold packs

Which invention uses liquids that are very cold and absorb heat?

Cold packs, for bruises are one invention.

Do hyenas work in packs?


Can you use ammonium nitrate as garden fertilizer i have it in the form of used chemical cold packs?

Ammonium nitrate is a common ingredient in fertilizers. Whether used cold packs are suitable for fertilizer or not depends on what else is in them.

Will The Sims 2 extension packs work on sims 3?

no just like the sims expantion packs don't work on the sims 2

What are some Cooling treatments?

Sponge baths, cold compresses, and cold packs are all wet cooling treatments

Where can you find ammonium nirate?

inside most instant cold packs