Lesson 1: Explore the concepts of energy
One of the most fundamental properties of living cells systems is their ability to utilize and transform energy. Recall that in order for us to do activities such as walking and running, we need energy which can be defined as the ability to do work. Work is considered to be done when a force is applied to an object which causes it to move from its position of its state of motion. Think about it in the sense of kicking a ball or roller skating. There are two fundamental types of energy: kinetic and potential energy. Both types of energy can be found in many forms such as mechanical, electrical, electromagnetic, chemical, thermal and atomic. Kinetic energy is the energy that moving objects possess whereas potential energy is the energy that an object stores.
Check out these two great YouTube videos below for more information about kinetic and potential energy. The catchy songs will help you remember the difference and will provide you with more examples of the two fundamental types of energy. Click on the images below which will direct you to the videos.
Lesson 2 & 3: Introduction to Thermodynamics
In this lesson, you will learn about the First Law and the Second Law of Thermodynamics.
Why do we need a constant supply of food? When thinking about this, recall the introduction to metabolism and why it is important for us to have these processes.
The food which we consume provides us with energy that is needed in order of keeping our bodies alive. We need to have a constant and healthy supply of food because almost every process that happens within our bodies depends on energy. The calories, contained within our food, provides us with sufficient energy if it is consumed in good proportions. These vital nutrients are digested, absorbed and circulated within our bodies and then gets delivered to our cells. This energy from our consumption of food then gets converted into mechanical energy that allows us to do activities such as running, riding a bike and even thinking. However, some of this energy is not transformed and will be released from our bodies as heat. This causes us to sweat and feel warm.
Try out the Popping Popcorn Activity below to help you understand the First Law of Thermodynamics.
Why do we need a constant supply of food? When thinking about this, recall the introduction to metabolism and why it is important for us to have these processes.
The food which we consume provides us with energy that is needed in order of keeping our bodies alive. We need to have a constant and healthy supply of food because almost every process that happens within our bodies depends on energy. The calories, contained within our food, provides us with sufficient energy if it is consumed in good proportions. These vital nutrients are digested, absorbed and circulated within our bodies and then gets delivered to our cells. This energy from our consumption of food then gets converted into mechanical energy that allows us to do activities such as running, riding a bike and even thinking. However, some of this energy is not transformed and will be released from our bodies as heat. This causes us to sweat and feel warm.
Try out the Popping Popcorn Activity below to help you understand the First Law of Thermodynamics.
What you will need:
What to do:
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QUESTION: What quantity was added to our thermodynamic system when the pot was placed over the hotplate?
Due to the heat caused by the hotplate, we can see that energy was added into our system. This is due to conduction. Recall that conduction is the transfer of heat from a substance of higher temperature (hotplate) to a substance of lower temperature (pot with popcorn).
QUESTION: What happened to the kernels after the heat was supplied?
We saw the kernels begin to pop and expand once we added energy into our system. The temperature of the popcorn increased and we saw its expansion in volume. Due to the change of the state of the popcorn and by heating the system, we know that its internal energy increased.
QUESTION: What happened to the lid of the pot as the popcorn kernels popped?
We observed that the pot's lid began moving up as the popcorn pushed its way out of the pot. This is because the popcorn expanded in volume and needed more space for other popcorns to expand. This is a form of work which the popcorn has done.
Due to the heat caused by the hotplate, we can see that energy was added into our system. This is due to conduction. Recall that conduction is the transfer of heat from a substance of higher temperature (hotplate) to a substance of lower temperature (pot with popcorn).
QUESTION: What happened to the kernels after the heat was supplied?
We saw the kernels begin to pop and expand once we added energy into our system. The temperature of the popcorn increased and we saw its expansion in volume. Due to the change of the state of the popcorn and by heating the system, we know that its internal energy increased.
QUESTION: What happened to the lid of the pot as the popcorn kernels popped?
We observed that the pot's lid began moving up as the popcorn pushed its way out of the pot. This is because the popcorn expanded in volume and needed more space for other popcorns to expand. This is a form of work which the popcorn has done.
First Law of Thermodynamics
We know that the total amount of energy in the universe is constant. This means that energy cannot be created or destroyed. This is also known as the law of conservation of energy. Energy can only be converted from one form into another. If an object or process gains an amount of energy, it does so at the expense of a loss in energy somewhere else in the universe.
The first law of thermodynamics states that the heat added to a system is equal to the sum of the increase in internal energy plus the external work done by the system. It can be represented by the mathematics equation which you can see on the right.
This means: heat input = increase in internal energy + work output
Click on the image below to check out the YouTube video for another demonstration of the First Law of Thermodynamics.
The first law of thermodynamics states that the heat added to a system is equal to the sum of the increase in internal energy plus the external work done by the system. It can be represented by the mathematics equation which you can see on the right.
This means: heat input = increase in internal energy + work output
Click on the image below to check out the YouTube video for another demonstration of the First Law of Thermodynamics.
Try out the Heating Sand by Shaking It Activity below to help you further understand the First Law of Thermodynamics.
What you will need:
What to do:
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What Happened?
You should have observed that the sand's temperature increased from 65 degrees Fahrenheit to 68. This is because by shaking the sand, we created friction between the particles which converted the kinetic energy produced to heat energy and hence the temperature changed.
You should have observed that the sand's temperature increased from 65 degrees Fahrenheit to 68. This is because by shaking the sand, we created friction between the particles which converted the kinetic energy produced to heat energy and hence the temperature changed.
Second Law of Thermodynamics
Try the following activity to observe the Second Law of Thermodynamics in action!
What you will need:
- 2
blocks of metals of the same size and dimensions
- Thermometer
What to do:
- Place one
block of metal in the freezer for about 10 minutes. Before taking it out
from the freezer, measure its temperature using a thermometer.
- At the same time, put the other block over fire or immerse it in boiling water. Measure its temperature also.
- Get the two blocks and place them in contact for 3 – 5 minutes. Get the temperature of each block.
- Record your data.
Question: What did you observe in the experiment? After the blocks are placed in contact, what happened to their temperatures?
You should have observed a temperature change in both blocks of metals as the hot block cooled down whereas the cold block warmed up. Due to the hot block's decrease in the temperature, we can say that heat escaped that block and was transferred to the colder block and to the surroundings.
This is a clear observation on the direction of heat. Recall that heat always travels from an object of internal energy at higher temperature to object of internal energy of lower temperature. The second law of thermodynamics states that the entropy of the universe increases with any change that occurs. It can be represented by the mathematical equation ΔS universe > 0.