## Ready to Take the Plunge!

• Lesson
3-5
2

Students will work in pairs on various measurement problems. They will complete linear conversions, find elapsed time, calculate a percentage, and analyze data from a chart.

This lesson contains a lot of material; an appropriate stopping point is indicated, should you need to teach this lesson over two days.

To begin, pair students with their previous partner at a computer. Ask them to think back to the web they created at the beginning of the unit, "Math Used in Scuba Diving." Have students add any new ideas they've realized since the beginning of the unit. If students do not mention boat speed, elapsed time, and dive depth, suggest these ideas to prepare students for today's activities.

Show the video clip of a dive to spark student interest. In fact, even if students saw the video in the lesson Belize's Barrier Reef, it would be beneficial for students to view it again now.

Scuba Diving Video Clip

For the activities in this lesson, students should have a good understanding of several topics; depending on student background, you may want to review some or all of the following:

• Yards, feet, and inches
• Percentages
• Vocabulary related to scuba diving (eg. buoyant, depth, descent)
• How divers should descend (Ask students if they've had their ears pop, or felt the pressure at the bottom of a pool. Divers need to be careful to go slow enough to let their ears pop, so that the pressure doesn't build up.)
 Ready to Take the Plunge! Activity Sheet

Pass out the Ready to Take the Plunge! activity sheet and go over the directions. Students may need some help with vocabulary, but encourage them to work with their partner to complete the questions. As students are working, assess their understanding of the concepts. If students are having difficulty or making mistakes, be sure to ask questions to get them back on track rather than giving them the answer. This activity will take some time for students to complete, so you may prefer to complete the rest of this lesson at another time, possibly on a subsequent day.

Start the second portion of the lesson reviewing the activity sheet, Ready to Take the Plunge!. Have students share their strategies for solving as you go through the questions.

Remind students that the reason for the dive trip is to collect and analyze data to help the Coral Reef Preservation Society of Central America better protect the animals and plants that live on the reef. You may want to re-read Letter to the Students from lesson 1. Remind students of the various ways that our oceans are being polluted (trash, human contact, over-fishing, oil spills, etc.).

 Dive Data Activity Sheet

With students in pairs, distribute the Dive Data activity sheet (1 for each student). Read the introduction and directions with students. Depending on the amount of time you have for this lesson, students can either begin the activity by searching for each of the species using a search engine (eg. Yahoo or Google), or you can project images of the species for the students. Then, give students time to analyze data from the chart and answer the questions.

As students are working, be sure to circulate around the room and observe their conclusions. Depending on their prior knowledge, students may need help with some vocabulary (eg. trend, decline, certain, unlikely).

Gather students back together as a whole class, and discuss the results of the research. Prompt students:

• How can we use this data to predict what things will be like in the future?
• Based on the data, what do you predict will happen?
• What do you think could have caused the decline? How do you know? [Students should use information off of the activity sheet, as well as infer causes from their background knowledge. For example, they may state that there might be fewer schools of small fish for the animals to feed on.]

To close the lesson, chart a list of potential causes for the environmental changes. If time, draft a letter to the Coral Reef Preservation Society explaining the impact on the environment and what should be done to protect the wildlife.

Assessments

1. Work one-on-one with students while they are completing the first activity sheet, Ready to Take the Plunge. Are they calculating elapsed time effectively? Are they working with more ease than in the previous lessons?
2. Observe students as they work in pairs. Are they verbalizing their ideas to their partner? Are they listening to each other's strategies?

Extensions

1. Create a brochure about scuba diving in Belize or about saving the Barrier Reef.
2. Create a double bar graph or two circle graphs to compare the data collected on the dives (last year's and this year's data).
3. As a creative closing to the unit, have students write an ending for the trip. Have them share their stories with the class.

Questions for Students

1. The speed limit for cars is 65 mph, and some planes can travel faster than 400 mph. Why do you suppose your dive boat travels at an average speed of only 20 mph?
[It wouldn't be safe to go that speed in a boat, as there are no seat belts. Also, with the divers and all of their equipment, the boat will go slower than when just carrying the captain.]
2. If the weight needed for your weight belt is 5% of your body weight, how could you calculate 10% of your body weight without using a calculator?
3. You could double the weight you have in your belt, or you could divide your weight by 10 to get 10%. For example, if you weigh 80 lbs, 10% of your weight would be 8 lbs. If you weigh 87 lbs, round your weight to 90; 10% of 90 is 9 lbs.]
4. What do you predict would happen if a diver wears too much weight in their weight belt? Why?
[The diver might descend too rapidly, causing ear damage. Students might also suggest that the diver could put more air in their BCD, as that will help keep them afloat.]
5. When you scuba dive, do you think it is important to wear a watch?
[Answers may vary. Yes, because if the dive guide says the dive will be 50 minutes, you will need to know when to come back up to the boat; no, because you should watch your air gauge, not your watch. If your air starts to get low, you need to come to the surface.]

Teacher Reflection

• Were students able to calculate elapsed time more easily than in previous lessons? If not, what seemed to be the most challenging part for the students?
• Did this lesson hold students' enthusiasm?
• Were any concepts presented too abstractly? If so, what adjustments were made while teaching this lesson?
• Are students becoming more independent as they work through the activities in this series of lessons? If not, what do they need to progress on their own?

### Belize's Barrier Reef

3-5
In this lesson, students will view several websites and determine what mathematical ideas and concepts are involved in scuba diving. The emphasis is on using technology to help students gain an understanding of how math is used outside of a school setting.

### What Time is it in Belize?

3-5
Students will calculate differences in time zones and explore the effects of traveling across time zones.

### Preparing for the Trip

3-5
In this lesson, students will use various resources to choose travel dates, compare temperatures, estimate and calculate distances to Belize City, and determine the length of their flight in preparation for a "trip" to Belize.

### Getting Ready for the Dives

3-5
In this lesson, students will pretend to travel to the island of Ambergris Caye off the coast of Belize. Students will work together to complete the measurements needed for their scuba diving gear in preparation for the dives, and they will solve elapsed time problems.

### Learning Objectives

Students will:

• Calculate elapsed time
• Calculate percentages
• Read and interpret tables and charts
• Solve measurement problems

### Common Core State Standards – Mathematics

• CCSS.Math.Content.3.MD.A.1
Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram.

• CCSS.Math.Content.3.MD.A.2
Measure and estimate liquid volumes and masses of objects using standard units of grams (g), kilograms (kg), and liters (l). Add, subtract, multiply, or divide to solve one-step word problems involving masses or volumes that are given in the same units, e.g., by using drawings (such as a beaker with a measurement scale) to represent the problem.

• CCSS.Math.Content.3.MD.B.4
Generate measurement data by measuring lengths using rulers marked with halves and fourths of an inch. Show the data by making a line plot, where the horizontal scale is marked off in appropriate units-- whole numbers, halves, or quarters.

• CCSS.Math.Content.4.MD.A.2
Use the four operations to solve word problems involving distances, intervals of time, liquid volumes, masses of objects, and money, including problems involving simple fractions or decimals, and problems that require expressing measurements given in a larger unit in terms of a smaller unit. Represent measurement quantities using diagrams such as number line diagrams that feature a measurement scale.

### Common Core State Standards – Practice

• CCSS.Math.Practice.MP1
Make sense of problems and persevere in solving them.
• CCSS.Math.Practice.MP4
Model with mathematics.
• CCSS.Math.Practice.MP5
Use appropriate tools strategically.
• CCSS.Math.Practice.MP7
Look for and make use of structure.