Lesson Plan | Technical Methodology | Nuclear Reaction: Half-Life

Objectives

Duration: 10 - 15 minutes

The purpose of this stage is to ensure that students understand the fundamental concepts of half-life, essential for the study of nuclear reactions. These concepts are applicable in various professional areas, such as nuclear medicine and engineering, promoting the development of practical skills that have a direct connection to the job market.

Main Objectives

1. Understand the concept of half-life in nuclear reactions.

2. Calculate the half-life of a radioactive sample.

3. Use half-life to determine the mass or concentration of a sample after a certain period of time.

Side Objectives

1. Relate the concept of half-life to practical examples from the job market, such as in nuclear medicine and industry.

Introduction

Duration: (10 - 15 minutes)

The purpose of this stage is to ensure that students understand the fundamental concepts of half-life, essential for the study of nuclear reactions. These concepts are applicable in various professional areas, such as nuclear medicine and engineering, promoting the development of practical skills that have a direct connection to the job market.

Contextualization

Half-life is a fundamental concept in nuclear reactions and has significant practical applications in various fields, such as nuclear medicine, where it is used in cancer treatment with radioisotopes, and in industry, in material dating processes. Understanding how half-life works allows not only for understanding the stability of radioactive elements but also for applying this knowledge in practical contexts that directly impact society.

Curiosities and Market Connection

In nuclear medicine, the half-life of radioisotopes is crucial for determining the correct dosage of radiation in tumor treatment, ensuring treatment efficacy and patient safety. In industry, half-life is used in the dating of archaeological artifacts through carbon-14, allowing the age of historical discoveries to be determined accurately. Fun fact: The element radium, discovered by Marie Curie, has a half-life of about 1600 years, making it useful in long-term studies of radioactivity.

Initial Activity

Provocative question: "How do you think scientists determine the age of a fossil or the exact dosage of a radiotherapy treatment?" Short video: Show a 3-4 minute video that dynamically and visually explains half-life and its practical applications, such as in medical treatments and archaeological dating.

Development

Duration: 50 - 60 minutes

The purpose of this stage is to provide students with a practical and applied understanding of the concept of half-life, allowing them to visualize and experience the process of radioactive decay. By engaging students in experimental activities and practical challenges, they will be able to consolidate their theoretical knowledge through practice, as well as develop analytical and problem-solving skills that are highly valued in the job market.

Covered Topics

1. Concept of half-life in nuclear reactions
2. Calculation of the half-life of a radioactive sample
3. Practical applications of half-life in nuclear medicine and industry
4. Methods to determine the mass or concentration of a sample after a certain time

Reflections on the Theme

Guide students to reflect on how the concept of half-life can be applied outside the classroom. Ask how this understanding might be useful in their future careers, whether in medicine, engineering, or any field involving radioactivity. Encourage them to think about how this knowledge might directly impact the work they will do in the future.

Mini Challenge

Maker Challenge: Simulation of Radioactive Decay

Students will construct a physical model that simulates the process of radioactive decay using simple materials such as gummy bears or coins. This hands-on activity will help visualize the concept of half-life and understand how the amount of a radioactive substance decreases over time.

Instructions

1. Divide the students into groups of 4-5 people.
2. Distribute 100 gummy bears or coins to each group.
3. Explain that each gummy bear or coin represents a radioactive atom.
4. Students should shake all the gummy bears/coins in a container and then count how many gummy bears/coins have 'decayed' (e.g., gummy bears showing a specific side up).
5. Record the number of gummy bears/coins that decayed and the number of gummy bears/coins remaining after each round.
6. Repeat the process until all gummy bears/coins have decayed.
7. Ask students to plot a graph of the number of remaining gummy bears/coins versus the number of rounds (time).

Objective: Visually and empirically understand the process of radioactive decay and the concept of half-life.

Duration: 25 - 30 minutes

Evaluation Exercises

1. Exercise 1: Calculate the half-life of a radioactive sample that takes 8 hours for 75% of its initial mass to decay.
2. Exercise 2: A sample of 200g of a radioisotope with a half-life of 5 years is left for 20 years. What will be the remaining mass of the sample after that period?
3. Exercise 3: A patient receives a dose of 50mg of a radioactive medication. If the half-life of the medication is 6 hours, what will be the mass of the medication in the patient's body after 18 hours?

Conclusion

Duration: (10 - 15 minutes)

The purpose of this stage is to consolidate the knowledge acquired by students, providing a clear view of how theoretical concepts apply in practice and in the job market. This stage also aims to wrap up the class with a reflection on the importance of the studied topic, motivating students to continue exploring the subject and recognizing its practical and professional value.

Discussion

Promote an open discussion with students about what they learned during the class. Question how the concept of half-life and the process of radioactive decay can be applied in different contexts outside the classroom, such as in nuclear medicine and industry. Encourage them to reflect on the challenges faced during the mini maker challenge and how these challenges can be compared to real problems faced by professionals in the job market. Facilitate a debate on the fixation exercises, discussing the different approaches to solving the presented problems.

Summary

Recap the main content covered during the class: the concept of half-life, how to calculate the half-life of a radioactive sample, and how to use half-life to determine the mass or concentration of a sample after a certain period of time. Reinforce the importance of understanding these concepts for practical application in fields like nuclear medicine and industry.

Closing

Explain to students how the class connected theory with practice through interactive activities and real examples. Highlight the importance of knowledge about half-life for various professions and how this can impact their future careers. Conclude the class by emphasizing the relevance of the studied topic for society and daily life, encouraging students to continue exploring the theme.