# Question Video: Understanding Specific Heat Capacity Physics • 9th Grade

4184 J of energy is needed to heat 1 kg of water by 1℃, but only 140 J is needed to heat 1 kg of mercury by 1℃. Which material has the higher specific heat capacity?

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### Video Transcript

4184 joules of energy is needed to heat one kilogram of water by one degree Celsius, but only 140 joules is needed to heat one kilogram of mercury by one degree Celsius.

Which material has the highest specific heat capacity? Now to answer this question, we first need to know what specific heat capacity actually means. Specific heat capacity is defined as the energy needed per unit mass per unit change in temperature.

In other words, how much energy do we need to put into a substance in order to increase the temperature by one degree Celsius of one kilogram of that substance? And luckily, that’s exactly what we’ve been told in the question.

We’ve been told that 4184 joules is the amount of energy needed to heat one kilogram of water by one degree Celsius. And we’ve been told 140 joules is the energy needed to heat one kilogram of mercury by one degree Celsius.

In other words, these values are simply the specific heat capacities of water and mercury respectively. So, all we need to do here is to compare the two values and state which one is larger.

Naturally, the value for water is larger. So, we can say that water has the highest specific heat capacity. Now of course what we could have done is simply just guessed that the larger value meant the largest specific heat capacity without understanding what specific heat capacity actually is, but don’t.

Always try and actually work out what the question is asking us to do. So anyway, our final answer is that water has the highest specific heat capacity.