Subject: Science and Engineering

Title: Stay Still

Topic: stability

Grade Level: Fifth

Stability in engineering refers to the ability of an object or structure to resist movement. Structures that are unstable have one or more components that can move freely in some direction. This is not always a bad thing. For instance, skyscrapers are built so that they can sway just a bit in heavy winds. The sway is usually dampened so that residents are not alarmed by the movement.

Desired Results

A. Established Goals

NCSCOS Competency Goal 4: The learner will conduct investigations and use appropriate technology to build an understanding of forces and motion in technological design.

B. Understandings

1. Students will understand that

Pushing and pulling forces on a structure or object can change its position and motion.
An object or structure is stable when the forces acting upon it are balanced by the composition of the object or structure itself.
Unbalanced forces can cause deformation or collapse of an object or structure.

2. Students will know

That some materials are better than others for constructing a particular object or structure
The purpose of the object or structure should be considered when choosing materials for construction

3. Students will be able to

Design a solution to a technological problem
Use models to understand how forces can act on an object or structure
Make informed choices about building materials

C. Essential Questions

What is the relationship of the materials used to construct an object or structure to the forces that will be acting upon it?

Assessment Evidence

A. Performance Task

Students will design and build an earthquake proof house that takes into account the forces acting upon it and the materials with which it will be built. The house will be tested in a “shake table”. Students will be assessed by the product itself as well as their analysis of the results of the test.

B. Other Evidence

Data sheets
Observations

Learning Plan: Time required for the activities in this lesson

Building Out-45 to 60 minutes
Skyscrapers-45 to 60 minutes
Revenge of the Crash Test Dummies-45 to 60 minutes
Earthquake-Proof Homes-2 sessions of 45-60 minutes

Activities

Activity 1: Building Out

Students will be using thin spaghetti noodles and tape to construct a cantilever that projects as far as possible out from the table without touching the floor.

Materials

Per group of students (6-8 groups)

1 box of thin spaghetti

1 roll of masking tape

1 ruler (to be used for measuring only)

Per pair of students (2 pairs per group)

scissors (to be used for cutting only)

pencil

data sheet

Set up:

1. Place the spaghetti and masking tape on each of the groups’ workstations.

2. Instruct students to divide the spaghetti noodles roughly in half.

Procedure:

1. Instruct students to use the materials to build a cantilever. They must make sure that it meets the specifications.

2. Allow 30-45 minutes for construction. Circulate to assess student progress.

3. At the end of the work time, have students measure the length of their cantilever from table’s edge to the end of the cantilever. They must also measure the distance from the floor to the tip of the cantilever.

Assessment:

1. Bring students together to discuss results. Ask what factors were critical to the cantilever’s stability.

2. Discuss what possible modifications students might suggest to their structures in order to improve stability.

3. Look at the data recorded by each group. Is there a relationship between the length of the cantilever and how close or far the tip was from the floor?

4. Review data sheets and check for understanding.

Activity 2: Skyscrapers

Materials:

large sheets of newsprint

paper or plastic cups, any size

paper plates, any size

large index cards

small index cards

plastic coffee stirrers

markers

masking tape

scissors

Set up: at each of 7 work stations place the following materials:

1 sheet newsprint paper

3 paper cups

3 paper plates

4 5” x 7” index cards

4 3” x 5” index cards

4 plastic coffee stirrers

1 marker

1 pair of scissors

At the supply table place the rest of the materials. One student from each group can come to get a forearm’s length of tape. They come back to get more tape as necessary within reason.

Procedure: For this lab, the planning and debriefing is at least as important as the product. Towers will be evaluated not only by their height, but by how well they stand up to a moderate breeze (demonstrate what that means during the introduction) how well construction went and well the team worked together. Emphasize that scientists have to do all of those things when they do a scientific investigation.

Step 1: Introduce the task. Tell students they must plan and build a tower that is as tall as possible, is freestanding (it cannot be supported by a table or chair in anyway) and can withstand a moderate breeze.

Step 2: Introduce the materials. Tell students that the materials can be used in pretty much any way they can think of.

Step 3: Students have to spend 5 minutes AS A GROUP planning how to use the materials to build a tower. They may use paper and pencil to plan if they desire.

Step 4: Students build the towers. If an idea is clearly not working, students should be encouraged to ditch the whole thing and plan a new design. Encourage students them to either plan and build a second tower if finished with the first one or improve the first one.

Step 5: When teams are finished, they should gather back on the floor. They should decide for themselves how well they think they worked together.

Step 6: Measure each tower and blow on it to establish the success or failure of the building.

Assessment

Use discussion and observation to establish student understanding. Have students sketch their towers and use arrows to indicate forces acting upon it.

Activity 3: Revenge of the Crash Test Dummies

Materials

Per pair of students

1 sheet recycled copy paper.

6 plastic straws

30 cm of masking tape

10 cm of duct tape (can be used only to attach wall to floor)

1 ruler (to be used for measuring only)

scissors (to be used for cutting only)

pencil

data sheet\

For testing station

1 large toy car, weighted so that it weighs about 600g-800g

ramp, about 1.5m-2m long

Supply table

Extra copy paper

Extra straws

Extra duct tape

Extra masking tape

Set up:

1. Create a testing station by setting up a ramp that is 50cm high and 1.5m-2m long. Place a barrier several meters away from the bottom of the ramp.

2. Weight the large toy car so that it weighs between 600g-800g. If you like, create faces and put them in the car to represent the crash test dummies.

3. Set out the materials on each table. Place the car at the testing station.

Procedure:

1. Instruct students to use the materials to build a wall. They must make sure that it meets the specifications.

2. When a wall is ready, student pairs will bring it to the testing station and get in line.

3. At the testing station, allow students 30 seconds to get it in place and ready for the test. Students may place the wall anywhere on the floor between the bottom of the ramp and 30cm away from the barrier. They may NOT place it directly in front of the barrier.

4. After 30 seconds of prep time, place the large toy car at the top of the ramp and let it go. The crash test dummies will ride their car into the wall.

5. The wall is a success if it shows little or no movement when the car hits it. If it collapses, crumples, allows the car to go through it or over it, it is not a success.

6. Instruct students to remove the wall after the test, return their workstations and record the results.

7. Students may continue to make modification on their wall or they can start a brand new one with new materials.

Assessment:

1. Bring students together to discuss results. Ask what factors were critical to the wall’s stability.

2. Discuss what possible modifications students might suggest to their walls in order to improve their stability.

3. Lead discussion on the testing procedure. Should everyone have been allowed to place their walls anywhere they wanted? What happened to walls placed at the bottom of the ramp compared to the walls placed farther away from the bottom? What testing modifications can students suggest to make the test more fair?

4. Review data sheets and check for understanding.

Performance Task Assessment: Earthquake-Proof Homes

For this task, a simple “shake table” is required. Attached are directions to a table that can be easily constructed. Design and construction of the houses will take place the first work session with the second session being devoted to testing and reflection. The challenge is to build a house that can withstand the shaking of an earthquake for at least 90 seconds without major structural damage. The house must have four walls and a roof. It must be at least 15 cm wide and 15 cm tall. Other features, such as doors, windows, etc. are not necessary.

Materials:

Allow students to choose from materials used in the previous activities. On their data sheet, they must note why they chose the materials---for strength, for flexibility, etc. Decide in advance how much of each material the students are allowed for their house. The materials available are:

thin spaghettimasking tape

large sheets of newsprintpaper or plastic cups, any size

paper plates, any sizelarge index cards

small index cardsplastic coffee stirrers

recycled copy paper.plastic straws

duct tape

Procedure:

First session

1. Each pair of students will discuss the possible materials and draw up a list of materials they want to use. Each material listed must be accompanied by a note on why it is being chosen.

2. Students will assemble materials and start construction.

3. The house must meet the following specifications:

It must have 4 walls
It must have a roof of some kind
It must be at least 15cm wide
It must be at least 15 cm tall
It must survive at least 90 seconds of shaking without significant structural damage

4. At the end of the work session, have students put aside the houses until the testing session.

Second session

1. Have students make a prediction about the outcome of the test on their house. Record on data sheet.

2. Each pair of students will place their house in the shake table in turn. They will have 30 seconds to get ready for the test. Decide in advance whether it is permissible for students to tape their house to the floor of the shake table box.

3. When the students and their house are ready, start the timer. Students will tug back and forth on the strings leading to the inner box of the shake table.

4. At the end of 90 seconds, stop the shaking and assess the results. Have students record on their data sheet. If time permits, students who have already tested may return to the workstation and fix or improve their houses.

Assessment

1. Bring students together to discuss results. Ask what factors were critical to the house’s stability.

2. Discuss what possible modifications students might suggest to their structure in order to improve their stability.

3. Lead discussion on the materials available for construction. Were some of them better than others? Would the students make different choices next time? How was this test a model for what happens to real homes during an earthquake? What were the limitations of the model?

4. Review data sheets and check for understanding.

Building Out

Names______

Can you defy gravity? Yes! With a cantilever! A cantilever is a projecting structure that is only attached or supported at one end.

The challenge for this activity is to build a structure that projects as far as possible from the edge of the table without ever touching the floor.

Specifications:

Only one half box of spaghetti noodles can be used.
Tape must be used in moderation. Overuse will result in disqualification.
Pencils, scissors and rulers cannot be used as part of the structure.
No part of the structure can touch the floor.

Procedure:

Discuss the task with your partner.
Divide up the spaghetti noodles with the other group at your workstation.
Choose a starting point on the table and begin construction.
When time is up, take two measurements: the total length of the structure from table to tip and the distance between the floor and the tip of the structure.

Record results below

Our cantilever was ______cm long.

The tip of our cantilever was ______cm from the floor.

Revenge of the Crash Test Dummies

Names______

Your Job: To design and build a wall capable of withstanding the impact of a speeding vehicle driven by angry crash test dummies.

The Scenario: Crash test dummies have done a lot for us. They are used in countless simulations to assess the safety of various vehicles and products. The results are used to protect people. Since they aren’t real, they can’t get hurt. But what if they had a chance to get a little revenge? Here’s their chance.

The Task: You are going to build a wall and the crash test dummies are going to try to demolish it with their car.

Specifications:

You may use the following materials:

1 sheet of paper
6 straws
30 cm of masking tape
10 cm of duct tape (only for anchoring the wall to the floor)
scissors (for use as a cutting tool only)
ruler (for use as a measuring tool only)

The wall must be at least be at least 15 cm wide and 15 cm high.

Procedure

1. Use the materials to build your wall. Make sure it meets the specifications.

2. When the wall is ready, take it to the testing station and get in line.

3. When it is your turn, you will have 30 seconds to get it ready for the test.

4. After 30 seconds, the crash test dummies will ride their car into the wall.

5. Remove your wall, return to your workstation and try again. Record the results on your data sheet.

Testing

To be considered a success, the wall must show little or no movement and it can’t bend or crumple when the car hits it. If the car goes through or past the wall altogether, the crash dummies win!

1. Place your wall on the line at the testing station. You have 30 seconds to do so.

2. When 30 seconds are up, the crash test dummies will travel down towards the wall.

3. After the test, assess the results and record them on the data sheet.

Results

Test # / Who won? / Why? / What will you do now?
1
2
3
4
5
You win if… / Crash Test Dummies win if…
The wall shows little or no movement / The wall collapses
The wall crumples
The car goes over the wall
The car goes through the wall

EarthQuake!

Names______

For this activity, you are going to use the knowledge you gained from the previous activities to design and build an earthquake proof home. Then, you are going to test your structure on a “shake table” and see if your house survives.

Specifications:

It must have 4 walls
It must have a roof of some kind
It must be at least 15cm wide
It must be at least 15 cm tall
It must survive at least 90 seconds of shaking without significant structural damage

Procedure:

1. You and your partner need to choose materials. You may chose from all of the materials you used in the previous three activities but you must write down WHY you are choosing them. The materials are:

thin spaghettimasking tape

large sheets of newsprintpaper or plastic cups, any size

paper plates, any sizelarge index cards

small index cardsplastic coffee stirrers

recycled copy paper.plastic straws

duct tape

We chose these materials / Because…

2. Using your chosen materials, construct the house. Make sure it meets the specifications.

3. On testing day, your house will be placed in the shake table box and shaken for 90 seconds.

4. Describe the results of the test below.