Heat | Grade 8 Science DepEd MELC Quarter 1 Module 4 Part 1

[Music] when we talk about heat what comes to mind you might think about fire or you might even think about temperature did you know that temperature and heat are not the same temperature and heat are often mistaken to be the same when heat increases we notice that the temperature of an object increases and this causes us to be confused usually we define temperature as the hotness or coldness of an object at the molecular level temperature is the average kinetic energy of the particles in a system average is used since each particle does not have the same kinetic energy with the other particles through the sense of touch we can determine whether an object is hot or cold for example when we touch a cup of coffee we can feel that it is hot on the other hand when we touch an ice cube we can feel that it is cold however this method is not accurate a tool used in measuring temperature is the thermometer the most common type of thermometer is the mercury in a glass tube but we also have the digital thermometer the international system unit of measurement for temperature is kelvin but there are other scales that can be used such as degree celsius and degree fahrenheit on the other hand heat is a form of energy that is transferred from one body to another due to the difference in temperature it is also a measure of the total kinetic and potential energy in a system heat is transferred from a body with higher temperature to a body with lower temperature for example when a person touches a cup of hot coffee heat is transferred from the cup towards the person's hand on the other hand when a person touches an ice cube heat will be transferred from the person's hand towards the ice cube a calorimeter is used in measuring the heat transferred from one body to another the international system unit of measurement for heat is joule sounds familiar right because it is the same unit we used for work and energy however calorie is more commonly used because it relates heat to the change in temperature a calorie is equal to 4.186 joules which is the amount of heat needed to change the temperature of 1 gram of water by 1 degree celsius all right let's perform this activity prepare three containers separately with cold water tap water and hot water and one tablespoon full of powdered drink for each of the three containers if you have someone who can help you ask for assistance so you can drop one tablespoon full of powdered drink into the three containers simultaneously it would be best if you drop them at the same time so you can see the difference in how the powdered drink travels in the hot tap and cold water in the containers carefully observe and compare the behavior of the powdered drink in the three containers focus your observations on the motion or speed of the spreading powder drink particles in three containers of water with different temperatures what have you observed as you drop the tablespoon of powdered drink into the three containers simultaneously you may have noticed that the powdered drink scattered and dissolved fastest in hot water then in tap water and lastly in cold water therefore we can say that the higher the temperature the faster the powder drink particles scattered they have a direct relationship towards each other now when we say heat it is the transfer of energy from high temperature to low temperature thermal energy measures the movement of particles as you have performed in the activity the amount of heat transferred relies on the amount of thermal energy thus heat is a measurement of thermal energy being transferred heat transfer can be determined when there is a change in temperature the higher the change in temperature the greater the amount of heat is transferred the smaller the absolute value of the change of temperature the smaller the amount of heat is transferred this means that heat is directly proportional to temperature heat may be absorbed or given off when heat is absorbed there is a positive change in temperature this means that the final temperature is higher than the initial temperature when heat is given off there is a negative change in temperature which means that the final temperature is lower than that of the initial temperature we have learned previously that objects possess kinetic energy even the small things that you cannot see also move and have kinetic energy the activity we had earlier showed that as the powder drink scattered in the water the particles of water are moving too we have also observed that the powdered drink scattered fastest in hot water and slowest in cold water [Music] thus we can say that if heat is absorbed by an object the particles of the object gain kinetic energy and they move faster since temperature is directly related to kinetic energy any gain in kinetic energy would cause the temperature to increase conversely if heat is transferred or removed from an object it loses kinetic energy its particles move slower and the body's temperature decreases thermal energy measures the movement of particles as you have performed in the activity it is the total kinetic energy of moving particles of matter it is dependent on the mass of the object and temperature the greater the mass that accounts for the number of molecules and temperature of an object the greater its thermal energy thermal energy varies since matter has varying mass with changing temperature which do you think has greater thermal energy between a cup of hot coffee and a large container of water at room temperature in this case a large container of water has greater thermal energy since the mass of the water in a large container is greater compared to the coffee in a cup this means that there are many more particles of water than coffee all these moving particles give the water in the large container greater total kinetic energy even though their average kinetic energy is less therefore the water in the large container has greater thermal energy than the coffee in a cup we already know that temperature is measured with the use of a thermometer the mercury column inside this thermometer either rises or drops when placed in contact with any object now why does the liquid inside the tube of thermometer go up or down this happens because the mercury inside the tube expands or contracts in response to a change in temperature when the thermometer bulb is placed in hot water the liquid inside the tube expands as it does it takes more space and so it goes up the tube when the bulb is placed in cold water the liquid inside the tube contracts and so it goes down the tube in physics this is called thermal expansion which is another effect of heat transfer but thermal expansion does not apply only to the liquid inside the thermometer in fact it applies to almost everything around us be it a solid a liquid or a gas now talking about solid liquid and gas these are called phases of matter there is another change that may occur when heat is added to or taken out from an object you may have noticed that an ice may melt into liquid water and water may evaporate when exposed to heat these are called phase change alright let's wrap things up we learned that temperature is not an energy while heat is heat is the measurement of thermal energy in a certain material or object it is also the transfer of thermal energy from high temperature to low temperature on the other hand temperature is a measure of the average kinetic energy of the particles the higher the temperature the faster the movement of the particles and the higher the kinetic energy the lower the temperature the slower the movement of the particles and the lower the kinetic energy temperature can be measured with the use of thermometers temperature is the measure of how hot or cold the material is while heat is a form of energy the units of temperature are kelvin celsius and fahrenheit while heat is measured in joules that's all for now stay tuned for the next part of this series about sound see you on our next video and don't forget to keep your minds busy if you like this video please subscribe to our channel and hit the notification icon for more videos like this

Channel: The Learning Bees

Views: 39,198

Keywords: The Learning Bees, Department of Education, DepEd, MELC-Based, Most Essential Learning Competencies, Science, Grade 8, Heat, Sound, Light, Heat Sound and Light, Temperature, Kinetic Energy, Calorie, Joules, Calorimeter, Thermal Energy, Thermal Expansion, Working Principle of a Mercury Thermometer, Mercury Thermometer, Thermometer, Phases of Matter, Solid Liquid and Gas, Heat Transfer

Id: J8d9ChbTfgQ

Length: 10min 53sec (653 seconds)

Published: Mon Nov 09 2020