Oysters & Organisms Lessons
68th
3
Classroom
Math
Summary
Students will compare various substances and discuss the difference between mass and volume. This will lead them to a discussion of density. The class will then jigsaw and each group will find the density of one substance. Then, the teacher will do a demo in which she creates a density column, and the class can see how liquids of different densities behave.
Objectives
What is density?
 How can the same ‘amount’ (volume) of a substance feel heavier?
Materials and Resources
Supplies
 1 large graduated cylinder (100 mL) (for the class)
 5 10 mL graduated cylinder
 ethanol dishwashing detergent (any brand, but should be colored, e.g. Dawn lemon)
 Dark corn syrup
 vegetable oil
 water
 4 50 mL cylinders, two full of molasses and two full of alcohol (enough for the whole class to pass around, so you might want to make 3 of each)
Before you get started
Tips for Teachers
Note for vocabulary: It is worth discussing with your students the difference between precise scientific terms and imprecise vernacular terms when discussing quantity. In particular contexts, think about: what do you mean when you say "amount" or "quantity"? Are you actually thinking of number? Volume? Mass? Something else? This lesson is structured as a jigsaw. Each group will compute the density of one substance and then the teacher will create the density column for the whole class. The reason for this is that it is very difficult for students to create a density column. If you get any materials on the side of the cylinder, the column will not look good. Make sure to practice the density column in advance. It helps to use a funnel to pour the substances in. Make sure the water is colored so that you can see that it is a different substance. For example, if your dish detergent is yellow, use blue for the water. In this lesson, we use the ideas of weight and mass interchangeably. Make sure students are clear on the difference before plunging in.
Preparation
N/A
Background
This lab introduces them to the idea that certain substances are denser than others. Density is a characteristic property of a substance. The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume). The mass of atoms, their size, and how they are arranged determine the density of a substance. The concept of density is essential to understanding how oysters filter. This lesson introduces density.
Instruction Plan
Engage
Pass out graduated cylinders that hold 50 mL of molasses and 50 mL of alcohol. The graduated cylinders must be the same size. First, ask what they know about molasses and alcohol? Ask if they're each some kind of water and/or contain water?
Now, Ask students to make observations about the two liquids.
Explore
Divide your class into five groups. Give each group 10 mL of one of the following substances and a scale.
ethanol
dishwashing detergent
dark corn syrup
vegetable oil
Water (colored blue)
Make sure to write the mass of the graduated cylinder on the board so that the students can subtract that from their total mass.
Explain
Introduce the formula for density. Explain that density is mass over volume (or how “heavy” something is divided by the space it takes up. In other words, how compact a substance is). This is a good time to give different examples of the uses of "amount" "more" and "less". Ask students how two objects that are more dense and less dense would feel. What is the difference?
Also, be sure to distinguish between volume and mass/weight!
Use the density calculation handout to have each group find the density of their substance.
Elaborate
Before beginning this section, have a discussion with students. Ask them to describe things that they think are very dense, and things they think are very rarified (opposite of dense). Then they can make hypotheses about the given substances. Write the name of every substance on the board. Ask for student hypotheses about the density rankings. Once students have proposed different hypotheses and explained their thought processes, rank the substances by the actual densities calculated by the students. Then, collect the samples and pour them into a large graduated cylinder with the most dense on the bottom (see picture on the next page). Now have a discussion about what they see, how it compares to their prediction, and what new insights and questions have come up.
Standards
CCLS  ELA Science & Technical Subjects

 Integrate information presented in different media or formats (e.g., visually, quantitatively) as well as in words to develop a coherent understanding of a topic or issue.
CCLS  Mathematics

 Reporting the number of observations.
NGSS  CrossCutting Concepts

Patterns
 Graphs, charts, and images can be used to identify patterns in data.

Scientific Knowledge Assumes an Order and Consistency in Natural Systems
 Science assumes that objects and events in natural systems occur in consistent patterns that are understandable through measurement and observation.
NGSS  Disciplinary Core Ideas

PS1.A: Structure and Properties of Matter
 Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.
NGSS  Science and Engineering Practices

Analyzing and Interpreting Data
 Analyze and interpret data to provide evidence for phenomena.

Constructing Explanations and Designing Solutions
 Apply scientific ideas to construct an explanation for realworld phenomena, examples, or events.
NYC Science Scope & Sequence  Units

Grade 7, Unit 2
 Energy and Matter
NYS Science Standards  Key Ideas

PS Key Idea 3
 Matter is made up of particles whose properties determine the observable characteristics of matter and its reactivity
NYS Science Standards  Major Understandings

 Substances have characteristic properties. Some of these properties include color, odor, phase at room temperature, density, solubility, heat and electrical conductivity, hardness, and boiling and freezing points.
 Density can be described as the amount of matter that is in a given amount of space. If two objects have equal volume, but one has more mass, the one with more mass is denser.
NYS Science Standards  MST

 Students will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to pose questions, seek answers, and develop solutions.
 Students will understand mathematics and become mathematically confident by communicating and reasoning mathematically, by applying mathematics in realworld settings, and by solving problems through the integrated study of number systems, geometry, algebra, data analysis, probability, and trigonometry.
 Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science