Designed for a 50 min. Class
Grade Level: 9th Grade Algebra Class
Materials: paper, pencil, calculator, Seaquarium brochure
Objective: The students will review and master conversion from the English system to the metric system. The students will use problem solving skills.
Mathematical concepts: Problem solving, conversion
NCTM Standards: Standard 1 Mathematical Problem Solving, Standard 13 Measurement
Procedure:
Take 5 min. to discuss the Miami Seaquarium, especially the 6 animals featured in the brochure: Atlantic Bottlenose Dolphin, Pacific White-sided Dolphin, West Indian Manatee, Killer Whale, California Sea Lion, and the Harbor Seal. Tell the students that this is a review lesson on conversion. First, list some conversion rates on the board, and tell the students to write them done.
1 lb. = .453592 kg (round to .45 when computing problems or use 2 lbs. for 1 kg)
1 ft. = .3048 m ( round to .3 or use 3ft. for 1 m)
1 ton = 4000 lb. = 1814.368 kg (round to 1814.37) { Have students calculate 1 ton by converting 4000 lbs. to kg}
Remind students of the importance of labeling their answers to show what the numbers represent.
Now, show 2 processes of conversion on the board using the Atlantic Bottlenose Dolphin from the brochure as an example.
Process 1: Conversion
10 ft. (.3 m )
1 ft. { Note: Explain how the units cancel out, and then you multiple}
Process 2: Cross Multiplication
.3 m = X m
1 ft. 10 ft. (Note: Remind students that units stay together)
Do another example using both methods for the weight of the dolphin.
440 lbs. (.45 kg) =198 kg X kg = .45 kg = 198 kg
11 lbs. 440 lbs. 1 lbs.
Ask the children to guide you though the examples of a 8 ft., 320 lbs. Atlantic Bottlenose Dolphin.
Now try some word problems.
Example 1: Three 400 lbs. Dolphins are in a tank with 10,000 kg of water. How many kilograms in the tank?
First, convert lbs. To kilograms.
400 lbs. (.45 kg/1 lbs.)= 180 kg
Then set up the problem.
3(180kg) + 10,000 kg = 10,540 kg
Example 2: How many 10 ft. Dolphins does it take to line up nose to tail to cover 100 m?
10 ft.(.3 m/ 1 ft.)= 3m
X( 3 m)=100m
X= 33.33
Therefore, it takes 34 Dolphins. {Explain why we round up in this case}
Evaluation: Use whatever time is left in class to begin homework assignment. The assignment is to complete this worksheet.
Seaquarium Animal Feet Meters Lbs. Kilograms
Pacific White-sided 7 200
Dolphin
West Indian Manatee 10 1000
Killer Whale 25 3 tons or
12000
lbs.
California Sea Lion 7 600
(male)
California Sea Lion 6 200
(female)
Harbor Seal 5 200
Solve:
How many 440 lbs. Dolphins are needed to weigh at least 900 kg?
Answer to the word problem: 4.54= 5 dolphins
References: Seaquarium Brochure
Contributors: Major: Kari Kupfer
Minor: Carol A. Marinas