Designing Model Designing Model MembranesMembranes

Day 2: Nature of Science and Engineering NSE 3-6 MSTP Region 11 Teacher Center

Today’s Trainers: Tamara Moore and Selcen Guzey

Engineering DesignEngineering DesignGoals

1. Teachers will connect engineering activities across the standards.2. Teachers will experience an integrated engineering and life science lesson

AgendaAgendaEngineering StandardsEngineering is Elementary (EiE)Just Passing Through: Designing

Model MembranesCorrelating the EiE unit to State

Standards

Connecting to the Connecting to the StandardsStandardsWhat standards were covered in

the “save the penguins” activity?How well did this activity address

the engineering standards? Which specific standards were addressed?

Connecting to the Connecting to the StandardsStandards

1. Energy appears in different forms, including heat and electromagnetism.

4.2.3.1.1 Describe the transfer of heat energy when a warm and a cool object are touching or placed near each other.

4.2.3.1.3 Compare materials that are conductors and insulators of heat and/or electricity.

2. Energy can be transformed within a system or transferred to other systems or the environment.

6.2.3.2.3 Describe how heat energy is transferred in conduction, convection and radiation.

Connecting to the Connecting to the StandardsStandards

2. Engineering design is the process of identifying problems, developing multiple solutions, selecting the best possible solution, and building the product.

4.1.2.2.1

Identify and investigate a design solution and describe how it was used to solve an everyday problem.

4.1.2.2.2

Generate ideas and possible constraints for solving a problem through engineering design.

4.1.2.2.3

Test and evaluate solutions, considering advantages and disadvantages of the engineering solution, and communicate the results effectively.

2. Engineering design is the process of devising products, processes and systems that address a need, capitalize on an opportunity, or solve a specific problem.

6.1.2.2.1

Apply and document an engineering design process that includes identifying criteria and constraints, making representations, testing and evaluation, and refining the design as needed to construct a product or system that solves a problem.

Connecting to the Connecting to the StandardsStandards

Nature of Nature of Science & Science & EngineeringEngineering

Pre-AssessmentPre-AssessmentComplete Pre-test

EiE-Engineering is EiE-Engineering is ElementaryElementaryEiE was developed by the Museum of

Science in Boston in 2003. Funded by NSF grant.

Integrate engineering and technology into science lessons that you currently teach.

Does not explicitly teach the science, adds on to deepen knowledge by combining one field of engineering with science content.

The units are not built upon each other; so they can be taught as a stand alone or in any order.

http://www.mos.org/EiE

EiE-Engineering is EiE-Engineering is ElementaryElementaryThe main goal of EiE:Increase children’s technological

literacy. Increase elementary educators’ abilities

to teach engineering and technology to their students.

Modify the educational systems to include engineering at the elementary level.

Conduct research and assessment to further the first three goals and contribute knowledge about engineering teaching and learning at the elementary level.

An Overview of EiE Kits for An Overview of EiE Kits for grade 3-5grade 3-5

Unit Title Science Topic Engineering Field

Water, Water Everywhere: Designing water filters Water Environmental

Marvelous Machines: Making Work Easier Simple Machines

Industrial

Sounds like Fun: Seeing Animal Sounds Sound Acoustic

Just Passing through: Designing Model Membranes Organisms Bioengineering

An Alarming Idea: Designing Alarm Circuits Electricity Electrical

A Stick in the Mud: Evaluating a Landscape Landforms Geotechnical

Thinking Inside the Box: Designing a Plant Package Plants Package

The Attraction is Obvious: Designing a Maglev System Magnetism Transportation

Now You are Cooking: Designing Solar Ovens Energy Green

A Long Way Down: Designing Parachutes Astronomy Aerospace

Solid as Rock: Replicating an Artifact Rocks and Minerals Materials

A Slick Solution: Cleaning an Oil Spill Ecosystem Environmental

Taking the Plunge: Designing Submersibles Sinking and Floating Ocean

EiE Story BooksEiE Story Books

Teacher GuideTeacher Guide

Each EiE Unit includes:Lesson plansDuplication Masters (e.g., student

handouts) leveled for Basic and Advanced abilities.

Assessment materialsReferences for background

resources

Teacher Guide Structure Teacher Guide Structure Overview Prep LessonLesson 1: Engineering StoryLesson II: A broader view of an

engineering fieldLesson III: Scientific data inform

engineering designLesson IV: Engineering design

challengeAssessment

More on EiE More on EiE

Story books: $6.99Teacher guides: $45

Materials kits: most around $300

EiE Educator Resources: search for content connections, multimedia tools, and supporting documents

Technology in a Bag Technology in a Bag ActivityActivityIn your group, discuss what comes

to mind when you hear the word “technology.”

Come and grab your mystery bag!Identify a technology in your bag!

◦What material is it made of?◦What problem does it solve?◦How else could you use it?◦What other materials could it be made

of?

1. Juan Daniel’s Futbol Frog (Prep: 10-15 min., lesson: 90-120 min.)

2. Biology Meets Technology (Prep: 10-25 min., lesson: 45-50 min.)

3. Exploring Membranes (Part I: Prep: 10-15 min., lesson: 45-50 min.,

Part II: Prep: 15-20 min., lesson: 55-60 min.)

4. Designing Model Membrane (Part I: prep: 10-15 min. lesson: 55-60 min., Part II: prep: 10-15 min. lesson: 45-50 min.)

Overview of “Overview of “Just Passing Just Passing Through: Designing Model Through: Designing Model MembranesMembranes” ”

Goals of the Story Book:The story presents context for

relevant science content and engineering design challenge.

It introduces science and engineering vocabulary and field of engineering.

Lesson I: Lesson I: Story of Juan Daniel’s Futbol FrogStory of Juan Daniel’s Futbol Frog

Story of Juan Daniel’s Futbol Story of Juan Daniel’s Futbol FrogFrogRead the story and then answer the

following questions individually:What part of the story did you like

most?Why was it important that Juan

Daniel learn about membranes and how they work?

Share your responses with someone next to you!

Kristin Peters, the Kristin Peters, the BioengineerBioengineer What does Kristin Peters do?

As a team discuss about bioengineering and the roles of bioengineers.

Many bioengineers , instead of creating new devices or materials, focus on learning just how that living tissue work. UCSD senior Lisa Serventi (pictured left) works in a lab studying the fluid that lubricates joints, figuring out how different molecules in the fluid help to lower friction.

BioengineeringBioengineering

Engineering Design CycleEngineering Design CycleWhat process did Ms. Peters

teach Juan Daniel about to help him solve his problem?

Introducing the EDPIntroducing the EDP

Individually complete the “Juan Daniel and the Engineering Design Process” worksheet.

Guiding question: How do bioengineers use natural objects to inspire human-made technologies?

1) As a team discuss the following questions:What technology did Juan Daniel design?What inspired his design?

2) Card game time!!!3) Individually complete the “Technology

Match-up worksheet.”

Lesson II: Lesson II: Biology Meets TechnologyBiology Meets Technology

MembraneMembraneWhy is it important for Juan Daniel

to keep his frog’s skin moist?

When Juan Daniel sees the waterfall, what does he realize about his design?

Why can’t Juan just fill the bowl with water and leave it covered?

As a team define the word “membrane” and discuss how membranes help organisms meet their basic needs.

A membrane is a structure that….

MembraneMembrane

Definition Definition

A membrane is a structure that organizes and maintains cells as separate and distinct molecular environments.

MembraneMembrane

All cells are surrounded by a cell membrane!

MembraneMembraneEpithelial tissue covers all

external surfaces, internal cavities, and organs

What are the functions of epithelial tissue?◦Protection◦Absorption◦Secretion

Membrane ModelsMembrane ModelsSimple Epithelium vs. Stratified

Epithelium

Single layer (frog skin) Multiple layers (human skin)

Guiding question: What are some properties of natural membranes and what materials might be good choices for designing a model membrane?

Part I:Raisin demonstrationEgg demonstrationIodine-cornstarch demonstration

Lesson III: Exploring Lesson III: Exploring MembranesMembranes

Raisin DemonstrationObserving:a)Dried raisinsb)Raisins that have been submerged in water

for 24 hoursc) Raisins that have been submerged in a

mixture of sand and water for 24 hoursd)Raisins that have been submerged in water

for 3 hours

Documenting:Individually complete the “Exploring Membranes: Raisin

Skin” worksheet

Lesson III: Exploring Lesson III: Exploring MembranesMembranes

Raisin Demonstration Raisin Demonstration What are your observations of

the soaked raisins?Why do the raisins swell when

soaked in water?◦ Raisin skin acts as a membrane and

allows water to pass through.How does the water travel across

the raisin membrane?

All cell membranes share a common structural organization:

Bilayers of phospholipidsHydrophilic head

Hydrophobic tail

The fluid mosaic model by S. J. Singer and G. L. Nicolson (1972).

Membrane StructureMembrane Structure

Membrane LipidsMembrane LipidsMembrane Lipids are the building

blocks of the membrane, they provide the basic structure.

Lipids include fat and cholesterol and do not dissolve in water.

A phospholipid is a lipid that contains phosphorus.

The lipid composition of different cell membranes varies! In addition to the phospolipids, animal cell membranes contain glycolipids and cholesterol.

Passive Transport-Passive Transport-DiffusionDiffusionDiffusion is the process by which

molecules move from an area of higher concentration to an area of lower concentration.

DiffusionDiffusionPassive Diffusion: A molecule

simply dissolves in the phospholipid bilayer. Direction to transport is determined by the concentrations (number of molecules per unit volume) of the molecule inside and outside. Ex: gases such as oxygen

More on Raisin More on Raisin DemonstrationDemonstrationWhat will happen when you put a

raisin in pure water for 48 hours?What will happen when you put a

fresh grape in salt water?◦ Membranes have holes that are too

small to see!◦ The high concentration of sugar

molecules inside the raisin creates a concentration gradient. Water flows inside when the raisin in placed in water.

◦ Membranes control the rate at which things pass through

Osmosis with EggOsmosis with Egg

Step 1: Obtain two eggs and two beakersStep 2: Pour vinegar into each beaker and add one egg to

each beaker of vinegar - leave them overnight.Step 3: Remove the eggs and rinse with water and weigh

each egg.Step 4: Pour distilled water into the Egg #1 beaker and

pour corn syrup into the Egg # 2 beakerStep 5: After 24 hours, observe each egg and measure the

mass of each egg.

What is the purpose of step 2? What do you think Egg #1 will look like at step 5? Why? What do you think Egg #2 will look like at step 5? Why? What will be the relative masses of the eggs at step 5?

Osmosis-The diffusion of the Osmosis-The diffusion of the water!water!Osmosis is the movement of

water across the membrane. Although water molecules are

polar, they are small enough to pass the membrane!

http://www.youtube-nocookie.com/watch?v=sdiJtDRJQEc&feature=related

More water Fewer dissolved substances

Less waterMore dissolved substances

Only certain molecules can pass through the membrane since it is semipermeable. Small uncharged molecules can diffuse freely through lipid barriers. The bilayer is impermeable to large molecules (e.g., glucose, ions)

The Cell Membrane is The Cell Membrane is SemipermeableSemipermeable

Osmosis with EggOsmosis with EggWhat we have learned:An egg is a large single cell

surrounded by membranes that lie just inside the shell.

The egg membrane behaves the same as the raisin membrane◦An egg in distilled water will gain

water by osmosis (diffusion)◦An egg in corn syrup will lose water

by osmosis (diffusion) and thus mass and circumference!

What happens when iodine and cornstarch mix?

Iodine plus cornstarch is blue in color

What do you think you will observe after six hours? Explain your prediction.

Lesson III:Lesson III:Iodine – Cornstarch DemoIodine – Cornstarch Demo

Fill cup 1 with cornstarch and then fill a baggie with a mixture of water and a few drops of iodine. Place the bag into cup 1 and wait 6 hours.

Fill cup 2 with a mixture of water and iodine and then fill a baggie with a mixture of water and a tablespoon of cornstarch. Place the bag into cup 2 and wait 6 hours.

More on Membrane More on Membrane StructureStructure

The cell membrane controls materials going into and out of the cell.

Membrane Proteins carry out specific functions.

Some of the proteins control the movement of the materials into and out of the cell.

Membrane ProteinsMembrane Proteins

Facilitated Diffusion: A molecule is carried by carrier or channel proteins via a concentration gradient. Ex: carbohydrates, amino acids.

Channel proteins form open pores Carrier proteins selectively bind the

molecules

Membrane ProteinsMembrane Proteins

Passive Transport: The movement of particles across a cell membrane without the use of energy by the cell is called passive transport.

Active Transport: A process of transporting particles that requires the cell to use energy is called active transport.

Transport Across Cell Transport Across Cell Membranes Membranes

If molecules are transported in an energetically unfavorable direction across membranes this process is called active transport.

Active TransportActive Transport

http://www.youtube-nocookie.com/watch?v=STzOiRqzzL4&feature=related

Iodine/starch Iodine/starch DemonstrationDemonstration

What we have learned:•Membranes are semi-permeable – they have small holes and molecules pass through them based on size (and charge).

•The cornstarch cannot pass through the holes in the dialysis tube since it is a big molecule. Iodine is a small molecule relative to cornstarch easily pass through the membrane (dialysis tube)•Human engineered structures can behave like cell membranes

Part II:Testing the performance of several

model membrane materials (e.g., coffee filter, cheese cloth, felt, aluminum foil, etc.)

As a team discuss the following questions:1. What materials might be good choices to design a model

membrane?2. Group materials that can let water pass through at a slow

rate. What properties do these materials have in common?3. Group materials that can let water pass through at a fast

rate. What properties do these materials have in common?

As a team test your materials (pour ½ cup of water and wait 30 seconds to measure how much water has passed) and complete “The Testing Model Membrane Materials” worksheet

Lesson III: Exploring the Lesson III: Exploring the MembranesMembranes

Lesson IV: Lesson IV: Designing a Model Designing a Model MembraneMembraneWhat is a model?

◦A system that explains, describes, or represents another system

◦Contains elements, operations, and relations that allow for logical relationships to emerge

◦Sometimes not sufficient to completely describe the system it represents If it is a useful model, it closely

approximates the system in a manner that people can use when working with the system without being unnecessarily complex

Guiding question: How can we design a model membrane based on what we have learned in this unit?

Part I: Planning, making model membranes, and testing. Use the engineering design cycle!!!

You have been hired by an engineering team to help Juan Daniel design a model membrane to protect his lucky frog while he plays fútbol.

1) As a team plan your model membrane!◦ A successful model membrane design should…◦ How much water do you think should pass

through your membrane? 2) Test your model! 3) Collect data 24 hours after you complete

Part I.

Lesson IV: Lesson IV: Designing a Model Designing a Model MembraneMembrane

Goal of Design After 24 Goal of Design After 24 HoursHours

Part II: Checking initial membrane designs, measuring the water that passes through the membranes, revising model membranes

We won’t have time to really do this part. If you want to continue on, consider the following questions:

How much water passed through your design?

Do you think your design was successful? Why or why not?

How can you improve your design?

Lesson IV: Lesson IV: Designing a Model Designing a Model MembraneMembrane

Implementation OptionsImplementation Options

After Science unit

Lesson Time to Complete(60 min sessions)

1. Juan Daniel’s Futbol Frog

2-3 sessions

2. Biology Meets Technology

1 session

3. Exploring Membranes

2 Sessions (Part 1, 2, )

4: Designing a Model Membrane

2 Sessions(Part 1, 2, )

Integrated with FOSS unit

Curriculum Lesson

FOSS: Structures of Life

Invest. 1: Seeds

FOSS: Structures of Life

Invest. 2: Growing Further

EiE : Just Passing Through

1. Juan Daniel’s Futbol Frog

EiE : Just Passing Through

2. Biology Meets Technology

FOSS: Structures of Life

Invest. 3: Meet the CrayfishInvest. 4/5: Snail/Beetles

EiE : Just Passing Through

3. Exploring Membranes

EiE : Just Passing Through

4: Designing a Model Membrane

Water, Water Everywhere: Water, Water Everywhere: Designing Water FiltersDesigning Water FiltersThis unit focuses on water cycle,

the human need for clean and safe drinking water, and the role of environmental engineers in providing and maintaining clear water.

Lesson 1: Story book Lesson II: Environmental engineersLesson III: Exploring filter materialsLesson IV: Designing a water filter

New ChallengeNew ChallengeYour frog also needs clean water.

Thus your membrane design should also be able to filter the contaminated water!

Time to redesign your membrane!

What have we learned about membranes?

As a team list five things that you have learned about the structure of a membrane and properties of a membrane.

Wrap-UpWrap-Up

Membranes consciously control what moves through them and what does not.

Model membranes are exactly the same as actual membranes.

If the holes in a membrane are invisible to the naked eye, nothing can pass through the membrane.

Skin is a membrane… in fact, story is wrong/EiE curriculum is misleading◦This is too much of a simplification

Misconceptions about Cell Misconceptions about Cell MembranesMembranes

Post-AssessmentPost-AssessmentComplete Post-test

An Overview of EiE Kits for Grade An Overview of EiE Kits for Grade 3-53-5

Unit Title Science Topic Engineering Field

Water, Water Everywhere: Designing water filters Water Environmental

Marvelous Machines: Making Work Easier Simple Machines

Industrial

Sounds like Fun: Seeing Animal Sounds Sound Acoustic

Just Passing through: Designing Model Membranes Organisms Bioengineering

An Alarming Idea: Designing Alarm Circuits Electricity Electrical

A Stick in the Mud: Evaluating a Landscape Landforms Geotechnical

Thinking Inside the Box: Designing a Plant Package Plants Package

The Attraction is Obvious: Designing a Maglev System Magnetism Transportation

Now You are Cooking: Designing Solar Ovens Energy Green

A Long Way Down: Designing Parachutes Astronomy Aerospace

Solid as Rock: Replicating an Artifact Rocks and Minerals Materials

A Slick Solution: Cleaning an Oil Spill Ecosystem Environmental

Taking the Plunge: Designing Submersibles Sinking and Floating Ocean

Correlate to State Correlate to State StandardsStandards

Engineering Standards

1Juan Daniel’s Frog

2Biology Meets Technology

3Exploring Membranes

4Designing a Model Membrane

Characteristics of Good Characteristics of Good Engineering CurriculaEngineering CurriculaContextScience/Math Content

◦(even better if there are other content too)

Scientific Inquiry◦Could include design of experiments

Engineering Design◦Design cycles ◦Redesign

Exit SlipExit SlipWhich of the EiE curricula are you

most interested in implementing? Why?

On a separate piece of paper, answer the question above and write one personal reflection from this training that you would like to share with the MSTP Instruction Team.

Turn this in as you leave.