Final answer:
Different substances have different specific heat values due to their unique molecular structures and bonding forces. Water has one of the highest specific heats, which is important for life on Earth. Specific heat values are usually measured and referenced in tables, and are considered constant over typical temperature ranges for calculations.
Step-by-step explanation:
Different substances have different values for specific heat because of the distinct molecular structures and bonding forces present within each substance. Specific heat can be described as the quantity of heat required to raise the temperature of one gram of a substance by one degree Celsius (1°C). The specific heat of water, for example, is significantly higher than that of many other substances, such as iron or glass, implying that water requires more energy to change its temperature.
The specific heat values for most substances must be measured and are often referenced in tables, such as Table 1.3 or Table 7.3.1. The specific heat of substances varies somewhat with temperature. However, this temperature dependence is generally weak except for gases. The specific heat is usually considered constant over a given temperature range for practical calculations.
Water's high specific heat is particularly significant for sustaining life on Earth, as it allows for the moderation of Earth's climate and helps organisms regulate their internal temperatures more effectively. The specific heats of some common substances can be seen in various tables, such as Table 12.3.1 or Table 14.1, which provide values like 4.184 J/g°C for liquid water and 0.449 J/g°C for iron.