Specific heat capacity is the amount of heat required to raise the temperature of a substance by 1 K. It is expressed in the units J/ (kg*K). A high specific heat of a substance means that a large amount of heat is required to raise the temperature of the substance. Water is the substance with the second highest known specific heat capacity. at 4186PJ/ (kg*K). To raise the temperature of 1 kg of water by 1 Kelvin requires 4. 186 KJ of heat. This is mainly due to the presence of a large number of hydrogen bonds between molecules of water. Water covers around 70% of the Earth\’s surface and its high specific heat plays a very important role as it is able to absorb a lot of heat without a significant rise in the temperature.
When temperatures decrease, the heat which is stored is released, restraining a rapid drop in temperature. The combined effect of these processes is a buffering of temperature on the Earth. A relatively constant temperature without spikes and drops is essential to sustain life, as most organisms require temperatures to remain within a narrow range for their survival.
Actually, it isn\’t. The planet could care less. But it IS important to US, and to all life on the planet. What that does, because water is everywhere on the planet, is to moderate temperature variations all over the planet.
Temperatures do vary quite a bit across the planet and throughout the year, but they would vary a lot more if our atmosphere were devoid of water vapor, which could happen only in the complete absence of all oceans, lakes, rivers, and other bodies of (liquid) water. And the enormous amount of liquid water in the oceans of Earth, also acts like a giant thermostat. (Did you know that if you could drain all the oceans away into one big ball in space, that it would be about 1000 miles in diameter? ) Besides the high specific heat of water, the high heat of vaporization and heat of fusion, take large amounts of any energy that is being transferred, and direct it into changes of state (between vapor and liquid; and between liquid and ice), and away from changing the temperature.
And all this temperature moderation helps make life possible. High specific heat of a substance means, of course, that it takes a lot of energy put in or taken out of it, to raise or lower its temperature by a given amount. In other words, adding or removing a given amount of energy has less effect on its temperature.