Specific Heat Capacity of Water – All You Must Know About

Nov 12, 2021 | Turito Team USA

specific-heat-capacity-of-water

Do you know why doctors suggest warm water gargles to heal ulcers, cuts, or wounds in the mouth? Or why when your car heats up, you pour water on the radiator pipes of the vehicle? The reason behind this is nothing but the specific heat capacity of water. If you have dipped your feet in cool water after walking on the hot sand on a beach, the specific heat capacity of water is to be thanked for. 

In today’s blog post, there is everything about the same – the specific heat of the water and how crucial it is in your day-to-day life. However, before telling you about the same, let us start with the definition of heat capacity, molar heat capacity, and specific heat capacity. If you know these terms, you can skip to the part below them. If not, keep reading! 

Heat, Molar, And Specific Heat Capacity 

While we are here today to discuss everything about the specific heat of water, it is important that before it, you know what exactly the specific heat is. Below, you can find all about the same. Let the scrolling begin. 

Terms Explained Ahead 

  • Heat Capacity: The capability of a material to absorb heat energy. 
  • Molar Heat Capacity: Total amount of heat (in joules) required to raise the temperature of 1 mole of a substance by 1 Kelvin. 
  • Specific Heat Capacity: Total amount of heat (in calories) required to raise the temperature of 1 gram of water by 1 degree Celsius. 

What Is Heat Capacity? 

It is a term in physics related to a form of energy, often called thermal energy. As you all know, energy has the power to transform from one form to another. However, in any case, it is impossible to destroy it. Rather, this energy is conserved. For instance, when you use a blender in the kitchen, it transforms electrical energy into mechanical energy. 

As per the branch of physics that deals with a system’s work and energy (thermodynamics), the higher the temperature of a certain material, the more is the amount of thermal energy in it. Further, if the given material is more in quantity, it will possess total thermal energy. Every kind of matter you come across has a certain temperature associated with it, depending on its type and amount. 

Further, when we talk on an atomic level, you may know that when a substance absorbs heat, it causes its molecules to vibrate. Also, as the temperature rises further, the energy of the vibrations increases more. In the case of solids, these vibrations take place at the place of the molecules only as they are tightly packed. 

However, when the molecules start to vibrate in a liquid or gas, they can rotate and move from one place to another. It is because the molecules have spaces between them in gasses and liquids. They are not tightly packed. This storage arrangement is one of the reasons why the heat capacities of liquids and gases are more than that of solids. 

What Is Molar Heat Capacity? 

Molar specific heat capacity or molar heat capacity (symbol: Cn) is the total heat needed to raise a given substance’s temperature (1 Mole). If we talk in S.I. units, it is the total amount of heat (in joules) required to raise the temperature of a substance (1 Mole), usually by 1 Kelvin. The formula of molar heat capacity is as follows: 

Cn = Q/ΔT 

In the above formula, Q and ΔT represent heat and change in temperature, respectively. Further, you must also know the S.I. unit of this heat capacity. It is the joule. So, you can express molar heat capacity in terms of J/mol·K. if we relate molar heat capacity to the specific heat capacity discussed below, you can say that it is the specific heat capacity per unit mass. 

What Is Specific Heat Capacity? 

Now, let us talk about the major term you must know while discussing the specific heat capacity of water. By definition, it is the total heat required to raise the temperature of the given unit mass of a substance by usually one degree. Let us simplify it for you. When you need to determine the specific heat values of any substance, you can do it this way. 

Imagine two similar materials placed in contact with one another. Both of these, initially, have different temperatures. As soon as they come in contact, the heat from the warmer material flows to the colder one. This happens until the material A and B are at the same temperature. Considering the law of conservation of energy, the heat gained by the colder material is equal to the heat lost by the warmer one. 

You can observe that when the colder substance absorbs heat energy from the warmer one, its temperature increases. However, when two different substances that have equal masses are given the same quantity of heat, one can see that the rise in temperature for both substances is different. It is due to the different heat capacities of these substances. 

Thus, heat capacity here is the amount of heat needed by the whole substance to raise its temperature by one degree. Here, if the mass of the given substance is unity, the heat capacity of the substance is called its specific heat or specific heat capacity.  

Molar Heat Capacity and Specific Heat Capacity 

Now that you know what molar and specific heat capacities are let us compare them. While the former indicates the heat capacity per mole, the latter is the heat capacity per unit mass. 

Key Takeaways from The Above Sections 

  • Heat capacity refers to how much heat you need to add to a substance (1 Mole) to raise its temperature by 1 degree Celsius. 
  • The heat capacity of solids is usually lower than that of liquids and gasses. 
  • Molar heat capacity indicates the heat capacity per mole of a molecule. Its SI unit is the joule, expressed in terms of J/mol·K. 
  • If the mass of the given substance is unity, the heat capacity of the substance is specific heat or specific heat capacity (CSP). 
  • CSP can thus be defined as the amount of heat needed to heat 1 gram of a material by one degree Celsius. 

Other Things You Need to Know About Specific Heat Capacity Formula 

Before discussing the water heat capacity, let us tell you more about specific heat capacity. Have a look: 

Specific Heat Capacity Formula 

You know that the formula for molar heat capacity (Cn) is equal to Q/ΔT. Here is the formula for specific heat capacity, as well. 

Q = C m ∆t 

In the above formula, Q stands for the total quantity of heat absorbed by a body. C is the Specific heat capacity of a substance (it depends on the nature of the material of the substance), and m is the mass of the body. Lastly, ∆t in the formula refers to the rise in temperature.  

Specific Heat Capacity Unit 

You must also know that its S.I. unit is J kg-1 K-1. Also, heat capacity is equal to specific heat multiplied by the mass of the substance. Now that you know enough about specific heat capacity let us move to the final part of the blog post – the specific heat capacity of water. Keep reading! 

What Is the Specific Heat Capacity of Water? 

By now, we are sure you know that some things heat up quickly, while the same happens in others at a slower pace. When it comes to water, its specific heat capacity is rather high, and it needs more energy to raise its temperature. This also means that it falls under the category of those substances that heat up slowly. 

So, the specific heat capacity of water is high. But do you know its exact value? Let us tell you about it. The exact value of the specific heat capacity of water is 4182 J/kg°C. Now, water is quite commonly occurring and an important substance in our life. Therefore, there is a special way to identify the total amount of heat energy needed to raise one gram of water by a calorie (one degree Celsius). 

Please note that the calories mentioned here are quite different from those you consume with food. Here, it is equal to 1,000 Calories. Due to this, the calories related to food are in kilocalories (kcals). Now, we have already told you that the specific heat capacity of water is high. But do you know that it is even higher than most other common substances? 

Yes, you read that right. Let us compare the specific heat capacity of some commonly occurring materials in our day-to-day life: 

Specific Heat Capacity of Some Other Materials 
  • Iron: 449 J/kg°C 
  • Wood 1300 – 2400 J/kg°C 
  • Oak Timber: 2400 J/kg°C 
  • Gold: 129 J/kg°C 
  • Air: 1005 J/kg°C 
  • Leather: 1500 J/kg°C 
  • Olive oil: 1790 J/kg°C 
  • Paper: 1336 J/kg°C 
  • Table Salt: 880 J/kg°C 
  • Quartz Sand: 830 J/kg°C 
  • Steel: 490 J/kg°C 

From the above list, you can see that the specific heat capacities of all these are lower than 4182 J/kg°C – the specific heat capacity of water. Now, let us tell you the reason behind this. Chemically, water that goes by the chemical formula H2O has two Hydrogen (H+) atoms and one oxygen (O-) atom. Both the H atoms are linked to the O atom by covalent bonds. 

The oxygen here is electronegative. It, therefore, attracts the shared electrons in the covalent bond. Here, you must note that every electronegative atom can draw electrons to itself. This is because one side (with H) has a partially positive charge while the other has a partially negative charge. 

We already know that opposite charges are naturally drawn to one another, and the same happens here, resulting in the formation of a weak hydrogen bond. Due to this weaker hydrogen bond, the molecules in water can flow past themselves and bond together. They are, thus, constantly forming and breaking the bonds resulting in the high specific heat capacity of water. 

Now, when you heat water, this energy is split. A part of it is used by water to break its bonds, and a part of the energy heats it. Due to this particular reason, water needs more energy to heat up than any other related substances. Let us take the example of a beach here. If you have ever been to a beach on a sunny day, you may have noticed its hot sand. 

As you walk on this hot sand, it is common for you to move towards the water there to cool off your feet. Now, on the same day when sand is hot, have you wondered why the water is cool? We will tell you the answer. This is the specific heat capacity of water (4182 J/kg°C) and sand (830 J/kg°C). The former has a high heat capacity while the latter has a low. 

Due to this, the temperature of sand rises even with less energy than water. Their energy source here is the sun, which offers a more or less constant energy rate. Again, as water has a high specific heat capacity, it needs more of this energy to raise its temperature by one degree Celsius, and you can enjoy cool water at the beach even on a scorching hot day. 

Top Benefits of The High Specific Heat Capacity of Water 

You know that water has the highest heat capacity of most other substances and all liquids. You also understand that due to the specific heat capacity of water, it not only takes a long time to heat but also to cool. This quality of water has a lot of advantages in our daily lives. Let us see how water’s high specific heat capacity is advantageous for us. Have a look: 

Water Is Used for Fomentation. 

The benefit of the high specific heat capacity of the water is its use in fomentation. For hot/medical fomentation, hot water bottles are used. It is because hot water tends to remain hot for a long time, irrespective of whether it gives off large quantities of heat in the process. Further, while taking a hot bath, you have also noticed that water remains hot for a longer time than on the bathroom floor. It is all due to the specific heat capacity of water. 

Water Is Used for Protection of Crops. 

The final benefit of water’s high specific heat capacity in our list is its use to protect crops. During the winter season, you may come across farmers filling up their fields with water at night. Since water does not cool down as fast, it protects the crops from frost. If they do not fill this water on a cold night, the temperature near the crops may fall quite low – in some countries; it even falls below 00C. 

Due to this sudden fall in the temperature at night, and no presence of water to control it, the veins of the plants freeze. Now, ice occupies more volume than water (due to the anomalous expansion of water). As a result, the veins of the plants can burst, and the crop is destroyed. Water sprinkled on the crops is the easiest and most affordable solution to prevent the temperature around the crop from falling below 00C at night. 

Water Is Used to Store Bottled Wines and Juices. 

Another benefit of water’s high specific heat capacity is storing juice and wine bottles. It is especially true for cold countries. Here, they place juice and wine bottles underwater. It prevents the content in the bottles from freezing for a long time. So, due to the high specific heat capacity of water, the content in the wine and juice bottles take a lot of time for their temperature to fall to zero degree Celsius or lower. 

Water Is Responsible for Land and Sea Breezes. 

As mentioned earlier, water’s specific heat capacity is more than that of sand. It is five times more than sand. Due to this, it takes much more time and energy to heat than it. Also, due to this quality, it has a hand in the land and sea breezes. Let us tell you how. When it comes to the sea breeze, the process is as follows. 

During the day, when the sun provides maximum heat, the land warms up much faster than the sea (again due to specific heat capacity). As the land heats up, the hot air rises and moves towards the sea while the cool air from the sea takes its place on the land. This gives rise to the cooling sea breeze. And this is the reason why the air on the seashore is cool during the day. 

Now, after sunset, the air mass above the sea loses heat slower than that of the air mass above the land. Since the air over the sea is hotter, it rises and moves towards the land. The cool air over the land then takes the place of the warm air over the sea. This reverses what happened earlier during the day and forms the land breeze that blows from land out to sea. 

Water Is Used for Enhanced Blood Circulation. 

Another benefit of water’s high specific heat capacity is its ability to act as a vasodilator. It means that when hot water comes in contact with any part of our body, it expands blood vessels, thereby enhancing blood circulation. 

This quality of water is one of the reasons why doctors recommend warm water gargles for the faster healing of injuries like ulcers, cuts, and wounds in the mouth. Also, as mentioned in medical fomentation, hot water compress can help relax our muscles and reduce pain. 

To Sum Up 

The specific heat capacity of water is very high and almost higher than most liquids. Due to this, it takes up more time to heat and an equal amount of time to lose its heat. This quality of water is quite beneficial in our day-to-day use. From protecting our food to acting as a vasodilator, the specific heat capacity of water serves many purposes to mankind. However, consider those different kinds of water (seawater and tap water) may have different specific heat capacities.


Book a free demo

Grade*

+91

By proceeding to create an account you are agreeing to our Terms of conditions and Privacy Policy