Context

The concept of latent heat is essential in the study of thermodynamics, which is the part of physics responsible for the study of heat and its transformations. This concept refers to the amount of energy (in the form of heat) that a substance needs to change its physical state without undergoing a change in temperature.

To better understand, let's consider water. When we heat it, it changes from a liquid state to a gaseous state. During this process, water absorbs a certain amount of energy (heat) from the environment to undergo this transformation. However, contrary to what we might expect, the temperature of the water does not change during this change of state. The energy that the water absorbed from the environment is being used to break the bonds between the water molecules in the liquid state, allowing them to move freely in the gaseous state. It is this energy required for the state transformation that we call latent heat.

Latent heat is of great importance for understanding natural phenomena and industrial processes. For example, it is essential to understand how cooling and heating cycles work, such as those in a refrigerator or an air conditioner. Furthermore, the concept of latent heat has important applications in meteorology, as it helps to understand the processes of evaporation and condensation that occur in the atmosphere, being essential for the formation of clouds and, consequently, for the occurrence of rain.

To deepen the study of latent heat, we suggest the following resources:

• Book: "Physics for Scientists and Engineers" - Paul A. Tipler, Gene Mosca.
• Video: "Latent Heat - Phase Changes" available on Professor Douglas Gomes' YouTube channel.
• Website: "Sensible and Latent Heat: How to Calculate, Formula, and Exercises", available on the Mundo Educação website (https://mundoeducacao.uol.com.br/fisica/calor-latente.htm).

These resources will help understand the theoretical foundations of latent heat, as well as its practical applications and how to perform calculations involving this concept.

It is important to remember that, in addition to theoretical knowledge, it is essential to carry out practical experiments that allow visualizing and experiencing the concepts studied. Therefore, in the next stage of this project, we will carry out a practical activity involving latent heat.

Practical Activity

Activity Title: Calculating the Latent Heat of Ice

Project Objective

To understand in practice the concept of latent heat through an experiment that allows calculating the latent heat of fusion of ice.

Detailed Project Description

Students, in groups of 3 to 5, will carry out a practical experiment to calculate the latent heat of ice. The experiment will consist of measuring the amount of heat needed to melt a certain amount of ice at a constant temperature.

Required Materials

• Scale
• Styrofoam or plastic container
• Thermometer
• Stopwatch
• Room temperature water
• Ice

Step by Step

1. Weigh a known amount of ice (for example, 200 g) and record the value.
2. Place the ice in the Styrofoam or plastic container.
3. Using the thermometer, check and record the initial temperature of the water.
4. Record the time it takes for the ice to completely melt.
5. During the process, monitor the water temperature, it should remain constant. If it starts to rise, it means all the ice has melted.
6. Once all the ice has melted, check and record the final temperature of the water.
7. Use the collected data and the latent heat formula to calculate the latent heat of fusion of ice.

During this project, each student will be responsible for a part of the experiment, whether measuring time, checking the temperature, weighing the ice, etc. This way, everyone will have the opportunity to actively participate in the project.

At the end of the experiment, students should discuss the results obtained, make comparisons with the theoretical value of the latent heat of fusion of ice, analyze possible errors, and draw conclusions.

Project Deliverables

At the end of the project, students must present a written report including the four main topics: Introduction, Development, Conclusions, and Bibliography used.

In the introduction, they should contextualize the topic of latent heat, its relevance and application in the real world, as well as the project's objective.

In the development, they should explain the theory of latent heat, describe the experiment carried out in detail, showing the methodology used and the results obtained.

The conclusions should include a discussion of the results, comparison with the theoretical value of the latent heat of ice fusion, analysis of possible errors made during the experiment, and what they learned from the project.

In the bibliography, they should indicate the sources used to support the work.

During the project and report writing, students should work collaboratively, distributing tasks in a balanced and complementary manner so that everyone actively participates in the process.

It is estimated that the completion of this project will require between 2 to 4 hours per student.