## Math Mission

## Opening

Analyze the following problem: "How many kilometers away is the lightning?"

Analyze the following problem: "How many kilometers away is the lightning?"

There is also a rule about lightning and thunder that works for kilometers rather than miles: *The distance of lightning in kilometers is the time between the appearance of the lightning and the sound of the thunder in seconds, divided by 3.*

Think about this rule and consider the following question:

- If there are 7 sec between the lightning and the sound of thunder, how far away is the lightning in kilometers?
- Follow the problem-solving process:
- Understand the situation.
- Represent the situation.
- Answer questions about the situation.
- Check that your answer makes sense.

VIDEO: Lightning and Thunder

- Use the problem-solving process to help guide your thinking.
- What is the independent variable in the problem situation? What is the dependent variable? How can you represent these variables on your graph?
- How can you use a ratio table to help you make your graph?
- What intervals and scale will you use for your graph?
- Include the units for all quantities—in calculations, graphs, tables, and so on—to help you make sense of the values.

Prepare a presentation about your findings.

- Compare your graph of the lightning and thunder formula in kilometers to your graph of the formula in miles. What is the same about the graphs? What is different?

Take notes about the process, strategies, and tools that your classmates used to solve the problem.

As your classmates present, ask questions such as:

- How did you determine which variable is the dependent variable and which is the independent variable? Why do you need to know this?
- How can you use the problem-solving process to ensure that you have a complete response?
- Can you explain the connections between your diagram and your formula?
- How is this problem similar to finding the number of miles away the lightning is? How is it different?
- Why is it important to specify the unit for every quantity in your work?
- How does knowing the time relationship between lightning and thunder help you calculate the distance of lightning?
- Did you have any errors in your thinking? If so, what were they and how can you correct them?
- What mathematical strategies are the most useful in solving a problem in which you are given a relationship between variables and asked to make predictions?

Write a reflection about the ideas discussed in class today. Use the sentence starter below if you find it to be helpful.

**Solving a lightning problem in miles helped me solve a lightning problem in kilometers in these ways …**