Introduction to Energy - Online Tutor, Practice Problems & Exam Prep

Introduction to Energy

In this video, we're going to begin our introduction to energy. And so energy is defined as the ability to perform work. And this term work can take on a lot of different meanings, but it's not referring to your homework in this sense. In biology specifically, work is referring to the transfer of energy that causes an overall change. And so really, energy can be defined as the ability to perform an overall change in a living system. Now in our course, we're going to talk about two different types of energy, potential energy and kinetic energy.

Now, potential energy is defined as energy that has potential. It is stored energy, and the stored energy is available to do work or to cause an overall change. Now, the second type of energy that you all should know is kinetic energy, and kinetic energy is the energy of motion. So, any substance that is moving or is in motion is going to have kinetic energy.

And so let's take a look at our image down below to distinguish between these two types of energy. And so notice on the left-hand side over here, we have this little chart where we have the energy types in the left-hand column, including potential energy, the storage form of energy, and kinetic energy, the energy of motion. And then we have examples of each of these types of energy. And so let's start off with the potential energy here.

There are different types of potential energy. There are different ways to store energy. So, one example of potential energy that is stored is gravitational potential energy. And so gravitational potential energy is going to be when something is going to have a lot of it and is going to be quite high with respect to something that has gravity. And so, for example, a biker that is on the top of a hill like this biker here, which is on the top of a hill, this image of the biker that you see here on the left is really just a screenshot of this image of the biker over here on the right. So, a biker that's at the top of a hill is not moving, but it still has high gravitational potential energy.

Now, another type of potential energy of stored energy is chemical potential energy. And chemical potential energy is when energy is stored in chemical bonds. And a classic example of a molecule that has chemical potential energy is glucose, which is the most abundant and the most common sugar that exists.

Now in terms of kinetic energy, the energy of motion, really all moving objects are going to have kinetic energy, including a biker that is actually coasting or moving really fast and is going to have kinetic energy. But also, muscle contractions are a form of kinetic energy. So when you flex your bicep or get up to go get a glass of water, those muscle contractions are considered a type of kinetic energy.

Now, let's take a look at this image over here on the right-hand side, which is also helping to distinguish between potential and kinetic energy. And so once again, a biker that's at the top of a hill, even though they're not moving whatsoever at the top of the hill, is going to have quite high gravitational potential energy. But as soon as this biker makes a dip in this direction, it's going to start coasting down the hill, moving really, really fast down the hill because gravity is acting on the biker. And so the biker, when it is moving, is going to have kinetic energy. And so the potential energy is going to be converted into kinetic energy as soon as the biker starts to move. And then when the biker makes it to the bottom of the hill, the biker is going to have low gravitational potential energy because it is no longer at the top of the hill.

This here concludes our introduction to the two main types of energy that we're going to talk about moving forward, potential energy and kinetic energy, and so we'll be able to get some practice in our next couple of videos. So I'll see you guys there.

Which of the following is an example of potential energy?

a) Water rushing over a water fall.

b) A glucose molecule.

c) A spring being released and expanding rapidly.

d) An ant foraging (moving around) for food.

• A. Water rushing over a water fall.
• B. A glucose molecule.
• C. A spring being released and expanding rapidly.
• D. An ant foraging (moving around) for food.

Which of the following is NOT a form of kinetic energy?

a) When the temperature of a substance rises causing the molecules of that substance to move faster.

b) When a hockey puck slides across the ice after being hit by a player.

c) When glucose molecules are broken down to create energy for cellular work.

d) When the molecules of the air vibrate transmitting soundwaves.

• A. When the temperature of a substance rises causing the molecules of that substance to move faster.
• B. When a hockey puck slides across the ice after being hit by a player.
• C. When glucose molecules are broken down to create energy for cellular work.
• D. When the molecules of the air vibrate transmitting soundwaves.

Thermodynamics: System vs. Surroundings

In this video, we're going to introduce thermodynamics and distinguish between the system and the surroundings. Thermodynamics is the study of energy transfers between different bodies of matter. It's really important in the study of thermodynamics to distinguish between the system and the surroundings. The system is defined as the specific portion of matter that's being studied. Depending on the scenario, the system can change drastically. In some scenarios, the system will be an entire living organism, and in other scenarios, the system will be just a single specific reaction. The system will really be any specific portion of matter that's going to be the main focus of the study. And then, of course, the surroundings are pretty much just going to be the surroundings that revolve around or surround the system. Everything else that's on the outside of the system will be part of the surroundings.

Biological systems are very interesting because they actually transfer both energy and mass with the surroundings. Let's take a look at our image down below to clear up this idea. Notice that in this particular scenario, the biological system is this plant that we have here in the middle. The biological system, this plant, is capable of allowing energy to enter the system, but it's also capable of allowing mass to enter the system. You can see that the solar energy from the sun is capable of entering the biological system, entering into the plant. Also, components that have mass, such as carbon dioxide gas and water molecules, are also capable of entering the biological system. On the other end, it's important to note that not only can energy and mass enter the system, but they can also exit the system as well. You can see that energy is capable of entering the system but then also exiting the system in a different form. Mass is also capable of entering the system but also exiting the system in a different form.

What you'll notice here is that this biological system is a plant and it's capable of performing photosynthesis and that's really what we're showing you here on this page. We'll get to talk a lot more about photosynthesis later in our course as we move forward. Basically what you can see here is solar energy is capable of entering, mass such as carbon dioxide and water are capable of entering the biological system. Then what ends up coming out of the biological system is glucose, which is a sugar and it is the most abundant sugar that exists. Recall from our last lesson video that glucose is a common form of chemical potential energy because all of these bonds that are formed in glucose contain chemical potential energy. It's a form of energy that's exiting the system here. Also, oxygen gas is a form of mass that's exiting the system. The main takeaway here is that biological systems are capable of allowing energy and mass to enter the system, but also, energy and mass can also exit the system in different forms. This concludes our introduction to thermodynamics and the distinguishing between the system and the surroundings, and we'll be able to get some practice applying these concepts as we move forward in our course. I'll see you all in our next video.

Why are the principles of thermodynamics important for the study of biology?

a) The principles of thermodynamics govern the chemical processes in all biological organisms.

b) The principles of thermodynamics govern how an organism exchanges energy with their environment.

c) The principles of thermodynamics govern how all life on Earth exchanges energy.

d) All of the above.

• A. The principles of thermodynamics govern the chemical processes in all biological organisms.
• B. The principles of thermodynamics govern how an organism exchanges energy with their environment.
• C. The principles of thermodynamics govern how all life on Earth exchanges energy.
• D. All of the above.

Which of the following is NOT an example of a biological system?

a) A human eating a cheeseburger.

b) A coral reef where energy and mass both enter and exit.

c) The digestive system of an organism absorbing food energy and discarding food waste.

d) The universe where the amount of energy and mass is constant.

• A. A human eating a cheeseburger.
• B. A coral reef where energy and mass both enter and exit.
• C. The digestive system of an organism absorbing food energy and discarding food waste.
• D. The universe where the amount of energy and mass is constant.