Oysters Post Lesson Plan | Brooklyn Bridge Park

Students will practice observing

trends in scientific data and calcu-

lating mean, median, and mode.

4-8

25-45 minutes

 Math worksheets (provided)

 Oyster measurement images

(provided)

 Whiteboard & marker

 Tape

Oysters are an important part of the

aquatic food web and help filter, or

clean, the water. One adult oyster can

filter 50 gallons of water a day. Oyster

populations in the New York Harbor

declined significantly due to high levels

of pollution in previous decades.

Although the waters have become less

polluted, scientists are still determining

how well oysters can survive and repro-

duce in these waterways today. Because

oysters filter the water, the health of oys-

ters helps assess the health of the water.

Scientists place oyster gardens in the

water to study the health and growth of

oysters. The oysters are monitored and

measured routinely to assess rate of

growth and mortality. A healthy oyster

may grow up to 1 inch per year.

When scientists collect a numerical set

of data, they often calculate the average,

also known as the mean. To further an-

alyze data, scientists may determine the

median and mode. The median is the

middle number in an ordered dataset

and the mode is the most frequent

number occurring in the dataset. These

measures of central tendency (mean,

median, and mode) help to represent a

large dataset with a single number.

Scientists often collect very large

amounts of data at a time. Calculating

the mean, median and mode helps

them interpret the data and observe

patterns.

1. While at the park, remember to collect the students’ data sheets after the end of the

program so that they can analyze their data back in the classroom.

2. Print, cut, and laminate the 10 provided oyster images. (To be used if introducing how

to calculate mean, median, and mode in a dataset)

3. Determine which activities in the lesson plan you will complete and print out a class set

of the corresponding worksheets:

 Activity 2 worksheet: Oyster Data: Mean, Median, Mode (1 page)

 Activity 3 worksheet: Oyster Data: Percentages & Trends Over Time (2 pages)

Have a whiteboard and marker available to demonstrate any equations or record the

averages calculated by students.

1. The math activities in this lesson plan involve calculating averages, percentages, and measures of

central tendencies. Depending on age, some parts of these activities may be skipped or modified.

2. If introducing mean, median, and mode to students for the first time, use the provided oyster cut outs.

Each oyster has a measurement listed in centimeters. Tape the 10 oysters on the board (place in a ran-

dom order). Tell students that this is an example of a set of oysters measured at Brooklyn Bridge Park.

Demonstrate or call a student up to arrange the oysters in number order from smallest to largest. Have

students record this list in their notebooks or paper.

3. Tell students to look over these measurements. What measurement appears the most? A: 5 cm, we call

this the mode. Sometimes there can be more than one mode. Remove two of the 5 cm oysters from the board.

What is the mode now? A: 4 and 6 cm, they both appear 3 times.

4. Next have students count the number of measurements in their list. A: 10 Ask what number is half way

between 10? A: 5 and 6, or 5.5 Have students figure out what the middle number, or median, is in this

data set by crossing one number off from each side until reaching the middle or having students count

to the 5th and 6th number. Explain to students that because we have an even number of measurements

we will need to take the average of the 5th and 6th numbers. In this case, both numbers are 5 and there-

fore the median is 5.

5. Lastly, tell students that they will calculate the mean, which is just another word for average. Remind

students that to find an average you add up all the measurements and divide by the number of measure-

ments you have (10). What do you notice about the mean, median, and mode? A: They are all 5 cm.

1. If your students have their oyster data sheets from their trip to Brooklyn Bridge Park, have students cir-

cle the number that appears most frequently on their datasheet. Have students draw a triangle around

the smallest number and a square around the largest number.

2. Next tell students to write their measurements out in order from smallest to largest on a separate piece

of paper. Have students determine the median number, providing instruction if needed.

3. Lastly, have students calculate the average length of the oysters they measured. For younger grades, re-

mind or explain to students that the average can be found by adding up all the measurements and divid-

ing by the number of measurements you took.

4. Ask students to raise their hands and share what their average was. Write theses numbers on the board.

If desired, you can use this new dataset created to calculate mean, median, mode, and range.

5. A healthy oyster will grow on average 1 inch or 2.5 cm per year. That means if a oyster is measured to be

about 10 cm (4 inches) long, the oyster is probably around 4 years old. Have students look at the average

size of the oysters they measured and estimate the age. Remember oysters grow 2.5 cm each year!

Billion Oyster Project

https://billionoysterproject.org

Oyster Lesson Plans

(Subject areas include: ELA, Math, Science, and Social Studies)

http://platform.bop.nyc

Estuaries 101 Curriculum

https://coast.noaa.gov/estuaries/curriculum/

1. Give each student a copy of the one page worksheet,

“Oyster Data: Mean, Median, and Mode.” Have stu-

dents complete as a class or homework assignment.

2. For this activity to be done independently, students

will need to know how to calculate mean, median,

mode, and identifying outliers.

1. For older groups, have students also complete the two

page worksheet, “Oyster Data: Percentages and

Trends Over Time.”

For this assignment, students should have experience

calculating percentages and be able to interpret a set

of data by observing changes and patterns over time.

Average: A number expressing the central or typi-

cal value in a set of data To calculate, add up all of

the numbers in a set and divide by the total num-

ber of items. Also known as the mean.

Interpret: To understand the meaning of signifi-

cance of something. When scientists interpret data

they are looking to draw conclusions about some-

thing they were studying.

Percent: A fraction where the denominator is 100.

It can be written using the sign, %.

Proportion: An equation stating that two ratios

are equivalent.

Mean: The average of all of the numbers in a sam-

ple. Add up all of the numbers in a set and divide

by the total number of items to calculate a mean.

Measures of Central Tendency: A single value

that can be used to describe the way in which a

group of data cluster around a central value. There

are three measures of central tendency: the mean,

the median, and the mode.

Median: The middle number in a series of num-

bers that's ordered from least to greatest. If there's

an even number of items in the data set, the medi-

an can be calculated by averaging the two middle

numbers.

Mode: the number that appears the most times in

the data set.

Mortality: The number of deaths in a given time

or scenario.

Outlier: Something situated far away from the rest

of the group. In math, this refers to a number

much smaller or larger that the other numbers in a

dataset.

Oyster Garden: A cage containing live oysters that

are monitored by students or scientists.

Oyster Reef: A group of oysters growing together

under the water.

Range: The difference between the highest and

lowest values.

 Reading Informational Text

 Speaking and Listening

 Literacy in Technical Subjects

 Literacy in Science

 Operations/Algebraic Thinking

 Number & Operations in Base

 Number & Operations-Fractions

 Counting and Cardinality

 Measurement and Data

 The Number System

 Expressions and Equations

 Quantities

 Ratios & Proportional Relation-

ships

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