In this part of the "trip" to Belize, students will be solving
elapsed time problems about a trip on a water taxi. As a starting
point, seat students with their partners and have them view a map of
Belize. A simple internet search should direct you to those maps. You may want to print a map for them or make a transparency. If your
students view the maps online, it would be a good idea to bookmark the
links due to the long URL addresses. You will also need to find a reliable diving site, which lists diving gear. Be sure to prepare these sites before class.
Distribute the Arriving in Belize
activity sheet (each student should have their own). Read the
introduction aloud, and explain to students that Ambergris Caye is an
island off of the coast of the country of Belize, and that it is a
popular place to visit due to its closeness to the barrier reef. Have
them find it on the map.
Next, go over the directions carefully with students; they will
be working both independently and collaboratively to complete the
questions. As students work, circulate and listen to the strategies
students are using to calculate elapsed time. Ask questions to check
for understanding (see #1 in "Questions for Students" below). You may
want to close this portion of the lesson by having students share
strategies with the whole class.
For the next portion of the lesson, students will be taking
measurements to determine the size of gear they will need. Ask
students, "What equipment will you need for the dives?" Have students
Think, Pair, and Share, and chart their responses. After allowing
students to brainstorm, direct them to diving websites to see if
there is other equipment that they did not list.
Distribute copies of the Scuba Gear Rental
activity sheet, one per pair. Review the gear names in the table. You
may want to have student pairs find each type of gear on the web sites
Before you start, it is important that students understand the following:
- The difference between inches/yards and centimeters/meters on their rulers, and the notation for feet and inches
- How to round their measurements [Note: The physical tools in
this lesson provide a good opportunity to teach basic rounding skills.
If an actual measurement occurs between two numbers on the ruler, the
student should choose the number that is closer to the actual
- What "head circumference" means
Go over the instructions with students, and pass out the rulers and
yardsticks. Set up the bathroom scale, and remind students that they
can do their measurements in any order (to eliminate wait time at the
scale). Circulate as students work to be sure students are choosing the
correct tool and using it accurately. Assess students as they work,
with questions such as:
- How did you figure out that you needed to order that particular size?
- If my shoe size is 7 1/2, what size fins would I need to rent? How do you know?
- My nephew is going to take a junior scuba class for kids under
8. He is 4'6" and 70 lbs. What size wetsuit should I buy for him? Why?
You may want to have students share their data with the group
(however, let them volunteer to share, as some students may be
self-conscious in sharing this type of information). Ask students why
they have different measurements.
Questions for Students
1. After students complete the Arriving in Belize City activity sheet: The water taxi should take about 50 minutes. Why do you suppose the time is stated as "about" 50 minutes instead of "exactly" 50 minutes? What factors could affect the length of the trip?
[The exact time cannot be given because the speed of the boat depends on the weather, wind, and number of stops. For example, bad weather or engine trouble could cause delays.]
2. While students are working on the Scuba Gear Rental activity sheet: Which tool, the ruler or tape measure, is most appropriate for measuring the circumference of your head?
[The tape measure is flexible, so this tool would be the better tool for measuring around your head than a ruler.]
3. After completing the Scuba Gear Rental activity sheet: Do you think all dive shops in Belize charge the same prices for the rental gear?
[Answers will vary; if a store charges too much, people may not shop at that store, but some stores may have higher prices because their equipment is nicer.]
- Calculate elapsed time
- Use measurement tools (ruler, meterstick, tape measure, scale) to perform measurements and determine sizes for their scuba gear rentals
- Read and interpret a schedule and table/chart
Common Core State Standards – Mathematics
Grade 3, Measurement & Data
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.
Grade 3, Measurement & Data
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.
Grade 3, Measurement & Data
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.
Grade 4, Measurement & Data
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
Make sense of problems and persevere in solving them.
Model with mathematics.
Use appropriate tools strategically.
Look for and make use of structure.