Temperature (Simplified) - Online Tutor, Practice Problems & Exam Prep

Temperature (Simplified) Concept 1

Now before we can talk about temperature, we first need to talk about the overall idea of energy. Energy is the capacity to do work or to produce heat. Now, heat is sometimes confused with temperature. They are not the same thing. What they are different subsets of what we call thermal energy. Now thermal energy is one of the subsets of energy itself. It's the sum of the kinetic and potential energies of all atoms in an object. Remember, kinetic energy is the energy of motion, potential energy is the energy of position. So we have energy, which can be broken down into thermal energy. Thermal energy can be further broken down into temperature and heat. Temperature is just the average kinetic energy of an object, a measurement of thermal energy. So when I say the temperature is 100 degrees Celsius, which is pretty high, that is what we refer to as temperature. It is a measurement of thermal energy. Heat, though, is not the same thing. Heat is just the flow of thermal energy from an object at a higher temperature to an object at a lower temperature. Remember, heat always moves from hotter to colder. So just remember, when we're talking about temperature and heat, they're not the same thing. Temperature is a measurement of thermal energy. Heat is the flow of thermal energy.

Temperature (Simplified) Example 1

Hey everyone. So here in this example question, it says, from the image provided below, determine which part of the cubes represent temperature and which part represents heat. So remember, heat itself just represents the flow of thermal energy from an object that's hotter to an object that's colder. If we take a look here, we have these 2 cubes and we can see that we have a set of wavy lines between them. These set of wavy lines themselves represent our heat. Temperature itself is a result of the movement of molecules within a given structure. So if we take a look here, we can see that in the first cube, let's call it cube 1, we can see that we have these little balls that are moving around. And in the second cube, cube 2, we have the same balls, but they're not moving as vigorously. We're going to say here temperature is really just the movement in each cube. So you could say that temperature is represented by the molecules moving in this cube as well as in this cube. Remember we said that heat is the flow of energy from a hotter object to a colder object. The objects in the first cube, we can see them moving more vigorously, more actively, therefore they would generate higher temperature. So we'd say that cube 1 would have a higher temperature, and the balls in the second cube are moving slower so they have a lower temperature. This reinforces the idea that heat, which we said are these wavy lines, would go from cube 1 to cube 2. They're going from a higher temperature to a lower temperature. So keep this in mind when learning the distinction between heat and temperature.

Which of the following containers would have the greatest flow of thermal energy in the form of heat?

• A.
• B.
• C.

Temperature (Simplified) Concept 2

Now, temperature can be measured in units of Celsius, Fahrenheit, and Kelvin. And when it comes to these temperature units, we can convert between them. In order to convert between them, we just have to utilize certain formulas. Now here we have purple boxes, and when we have these purple boxes, that means that, that's a term or formula you have to memorize. You have to commit it to memory because oftentimes it's not given to you on an exam or quiz.

The first one connects Kelvin to degrees Celsius, and it's that Kelvin equals degrees Celsius plus 273.15. Oftentimes, professors will drop the 0.15 part, but to be as accurate as possible, it's important that you use the whole number. From this equation, we can see that Kelvin directly connects to degrees Celsius, and we can go between them. The next equation connects degrees Fahrenheit to degrees Celsius, and the equation is:

F = 1.8 * C + 32

This formula shows us that degrees Celsius is connected to degrees Fahrenheit. From these three units, we can see that Celsius is in the middle. So, Celsius acts as the bridge that connects Kelvin to degrees Fahrenheit.

So just remember, when it comes to temperature, we have three units that we can use, and when it comes to changing between them, these are the two formulas you need to commit to memory. Anytime you see a purple box, remember, that means you're going to have to memorize either that term, that definition, or in this case, a formula.

Temperature (Simplified) Example 2

Let's take a look at the following example question. Here it says, one of the hottest recorded days in the country was 128 degrees Fahrenheit in Lake Havasu City, Arizona. If the melting point of phosphorus is 44.15 degrees Celsius, would it exist as a solid or liquid on this extremely hot day? Alright. So we see that in the question, we're dealing with units of Fahrenheit and Celsius. From the equations up above, we know it's the second one we're going to have to use in some way. So we have degrees Fahrenheit equals 1.8×C+32. They're giving me the temperature in Lake Havasu in Fahrenheit, but I need to compare it to this melting point of phosphorus, which is in Celsius. If the temperature I find is equal to or greater than 44.15 degrees Celsius, that means that phosphorus will melt, and it will be in its liquid form. If the temperature on this extremely hot day is not at least 44.15 degrees Celsius, then it won't be hot enough and phosphorus will not melt and remain a solid. So, I'm going to plug in what I have for Fahrenheit, which is 128, and this is 1.8C+32. Subtract 32 from both sides. So when we do that we get 96 equals 1.8×C. Divide both sides now by 1.8, and now we'll have the temperature in Lake Havasu in degrees Celsius. So our degrees Celsius here equals 53.3. Now we needed the temperature to be at least 44.15 degrees Celsius for phosphorus to melt. This answer is much greater than it. So, yes, it's hot enough for phosphorus to melt. Therefore, it will exist in its liquid form. Now that we've seen this example on how to relate Fahrenheit to degrees Celsius, move on to the next video, and let's take a look at the practice question.

At what temperature is the temperature in degrees Fahrenheit equal to the temperature in degrees Celsius?

• A. 0º
• B. 25º
• C. -40º
• D. -29º