hello everyone and welcome back to the pencil tutors channel my name is rafina and today i will be teaching the topic of specific heat capacity this is physics form 4 chapter 4.2 so without further ado let's get started first off what is heat capacity well heat capacity can be defined as the quantity of heat needed to raise the temperature of an object by 1 degree celsius and the formula for heat capacity is heat capacity is equals to the quantity of heat supplied divided by the change in temperature and the unit for heat capacity is as shown in the screen you can imagine heat capacity as how much energy would it take to raise the temperature of this substance by 1 degree celsius so let's say if you have an object let's say you have a pine of water that is at 27 degrees celsius so heat capacity refers to how much heat energy would it take to increase that pine of water from 27 degrees celsius to 28 degree celsius now that we've explored heat capacity let's find out what is specific heat capacity specific heat capacity is defined as the quantity of heat needed to raise the temperature of one kilogram mass of a substance or an object by one degree celsius now the biggest difference between heat capacity and specific heat capacity is the involvement of mass now because mass is involved the formula for specific heat capacity will also be a bit different than heat capacity the formula for specific heat capacity shows that it is equals to the quantity of heat supply divided by the product of mass and the change of temperature and the unit for specific heat capacity is as shown in the screen now an important thing to note is that quantity of heat that is absorbed or released by an object can be determined using the formula q is equals to the product of mass change of temperature and also specific heat capacity and this is actually a very important formula for you to know especially when you are answering paper to questions for this specific topic you should also understand that the higher the specific heat capacity more quantity of heat is needed to raise temperature of the substance and vice versa specific heat capacity is proportional to heat energy supply and inversely proportional to mass here are a few important formulas and relationships to know pause the screenshot [Music] let's explore some of the applications real world applications of specific heat capacity first off is in our cooking utensils as shown in the screen is a pot and also a wok so do you know that the handle of the pot is usually made from plastic well why is plastic specifically used this is because plastic has a high specific heat capacity and because it has a high specific heat capacity it gets hot very slowly and it is safe to handle next is at the wok and the body of pot now the wok is usually made from methyl and the body of pot is usually made from aluminum both of these materials has very low specific heat capacity and because of this they heat up very quickly therefore the food can be fried at a very high temperature in a short time so making the cooking process a bit easier another very important application of specific heat capacity lies within the nature in a phenomenon called sea breeze and land breeze now what exactly is sea breeze well sea breeze refers to the wind that is coming from the sea and the land refers to the wind coming from the land so what exactly are these two phenomenons let's look at sea breeze first well sea breeze happens in the daytime by nature the specific heat capacity of land is way less compared to c therefore because of this the temperature above the land rises more quickly compared to the sea and therefore the n above the land becomes hot and it will rises upwards and because of that the cold air from the sea will move towards the land and this will produce sea breeze now let's look at land breeze happens in the night time the specific heat capacity of sea is more than land therefore the temperature in the sea drops more slowly because they retain the heat much longer and therefore the hot air above the sea will rise upwards and the cold air above the land will move towards the sea and produce land breeze these two phenomenons are basically just vice versa of each other now that we've covered the applications definitions and formula let's look at some questions for this topic first off the question has given is a diagram which shows a heating curve for solid x of mass 0.8 kilogram the solid is heated with an immersion heater of 50 watts and the question has asked us to calculate the specific heat capacity of x now when we get a diagram of heating curve we know that it's a phase diagram which shows the transition of the substance from if it starts from a solid usually from solid solid to liquid and liquid and gas and now because specific heat capacity involves the raising of the temperature we will focus on this specific part of the heating curve now firstly when we get a question like this first thing you need to do is to write out all the information the question has given us so we know the mass of x is 0.8 kilogram the power of the heater is 50 watts and the time because we are focusing at this point only is 4 minutes which is equals to 240 seconds in sr unit now as we can see here the change in temperature is from 10 degrees celsius to 75 degrees celsius so that will be the number for our change in temperature it is very important to understand that heat is also a type of energy which means that heat can also be defined as the product of power and time as you can see here the formula for heat in terms of specific heat capacity is a product of mass specific capacity and also the change in temperature but because it is also a type of energy is also equals to the product of power and time which gives us the following formula and this uh formula or list of derivation is actually very important and usually these formula are the one that will give you a mark when answering these type of questions in your examinations so because of this we can actually substitute q with the product of power and time into the formula and when we substitute all of the information that we have into the formula we will get that the answer the specific heat capacity of x is as shown on the screen the next question has given us a diagram of four blocks p q r and s which are heated on the same stuff and the specific heat capacity of the blocks are given the question asks us which block will have the highest increase in temperature after being heated for 10 minutes so in this question the quantity of heat supply is constant because they are all heated on the same stuff and the time is also constant at 10 minutes so we should only be focusing on the specific heat capacity because this is the only factor in the increase in temperature of the blocks now an important thing to know is that the lower the specific heat capacity of a substance it means the substance will heat more quickly and the higher the specific heat capacity of a substance it means the substance will heat more slowly therefore in this circumstance in this question the block which will have the highest increase in temperature will be s because it has the lowest specific heat capacity which enables it to heat more quickly and has the highest increase in temperature so the answer will be a d now this is just some bonus notes so usually in the examination specific heat capacity is almost guaranteed will come out in the last section of paper two so it will usually give a question where they will give this these specifications of different items and they will ask us to explain the suitability of each characteristic and determine choose which is the most suitable product for the question that they want so usually for these type of questions an important thing to know is the specific heat capacity of different substances usually in the metal and the non-metal and to understand what is needed for each specification i'm not really going to go into this but you guys can pause the screen and read but please study like the specific heat capacity of different substances and understand like what is needed for each specification does this specification requires a low specific capacity does it require a heat conductor or heat resistant and you you need to understand those kinds of stuff for this question and that is all that i have for you today thank you so so much for watching if you enjoyed this video and learned something from it make sure to give us a thumbs up and subscribe to our channel for more videos like this in the future if you have any questions just drop them in the comment section down below in the future physics video will only be done according to the requests of the students therefore if there are any topics that you would like for me to cover just drop them in the comment sections down below and we will get right to it once again thank you so so much for watching and i'll see you guys around [Music]