Go Engineering!

(Provided courtesy of Science Netlinks and the American Association for the Advancement of Science)

In this lesson for Grades K-2, youngsters come to understand that there are limits to what the eye can see and that a magnifying glass can help extend those limits.

Context

Children come equipped with natural curiosity and creativity and have had many experiences with technology by the time they enter school. In particular, students may have been exposed to optical technology such as glasses, magnifying lenses, or even periscopes, microscopes, and telescopes. For this age group, classroom activities should begin to channel students’ inventive energy to increase their awareness and purposeful use of tools.

Standards

AAAS Benchmarks for Science Literacy state: By the end of the 2nd grade, students should know that

• Tools are used to do things better or more easily and to do some things that could not otherwise be done at all. In technology, tools are used to observe, measure, and make things. 3A/P1

• When trying to build something or to get something to work better, it usually helps to follow directions if there are any or to ask someone who has done it before for suggestions.

  Ideas in this lesson are also related to concepts found in the following AAAS benchmarks: By the end of the 2nd grade, students should know that

• People can often learn about things around them by just observing those things carefully, but sometimes they can learn more by doing something to the things and noting what happens. 1B/P1
• Tools such as thermometers, magnifiers, rulers, or balances often give more information about things than can be obtained by just observing things unaided. 1B/P2
• Describing things as accurately as possible is important in science because it enables people to compare their observations with those of others. 1B/P3
• When people give different descriptions of the same thing, it is usually a good idea to make some fresh observations instead of just arguing about who is right.

In this lesson, students will view objects of various sizes from several viewing distances to discover that their visual field is limited. Students will record what they see and will compare their observations with classmates in an open, nonjudgmental forum. They will have the opportunity to speculate about and experiment freely with magnifying glasses and will also conduct more structured experiments.

Planning Ahead

Materials:

Common objects of various sizes and shapes, such as blocks, coins, pencils, books, and erasers
Yardstick
Masking tape
Magnifying glasses
Draw What You See student sheet
Draw What You See with a Magnifying Glass student sheet
Set up several viewing stations in the classroom. Each station should include an object placed on a surface, such as a desk or a chair. Measure distances one, five, and ten feet from each station to serve as observation points. Clearly mark these with masking tape labeled with the correct distance, noted as “near,” “middle,” or “far.” (See the Motivation section for further explanation.)

Motivation

To begin this lesson, assign students to viewing stations. Explain that they will look at an object from three different distances—near, middle, and far—and will draw what they see. Then distribute the Draw What You See student sheet. Make sure that students locate the spaces on the student sheet where they should draw the object as they observe it from each observation point.

Have students stand at the closest observation point and draw what they see in the space provided. Have them then repeat the procedure at the other two observation points. Emphasize that they are to reproduce the size of the object as closely as they can.

Allow students to discuss how the size and distance of an object from their eyes affects how easy it is to see. Encourage students to look at other objects at various distances from them in the classroom to reinforce their formal observations.

Have them consider the following questions:

• Which object is easiest to see? Why?

• Are objects easier to see up close or far away?

Facilitate the discussion to make sure students understand that the larger and closer an object is to their eyes, the easier it is to see.

Development

Continue the discussion by asking the following questions:

• How small would the object you observed have to be before you couldn’t see it any more? How far away?

• What are some things you have trouble seeing?

• What can you do if an object is too small or too far away for you to see?

• Do you know of any tool that might help you see objects more easily?

Accept any answers to the first question, but make sure students understand that their vision is limited. As they discuss the second and third questions, point out that if they can’t move closer to an object, they can use tools such as the ones they mentioned—which might include glasses, magnifiers, binoculars, microscopes, and telescopes—to make the object appear larger and easier to see.

Then hand out magnifying glasses—one per viewing station or one per student, as available. Tell students what they are and ask if anyone has used one or knows anything about it. Have students look through the magnifying glass at each other and at objects around the classroom to get a feel for what it does.

Encourage students to experiment with the magnifying glass—looking through it with both eyes open and one eye closed and holding it at various distances from their eyes—to find the best way to use it. They will probably see best with the non-viewing eye closed and with the magnifying glass held five or six inches away from their face. Stress that there isn’t one “right” way to use the glass, but that they should find the way that works best for them.

Note: It’s important, however, that students do understand that the closer they hold the glass to an object, the larger the object appears. The Extensions section includes a website for an interactive tutorial students can do to reinforce this concept.

Once students have determined the way the magnifying glass works best for them, hand out the Draw What You See with a Magnifying Glass student sheet. Have students return to their viewing station and instruct them to view the object through the magnifying glass at each observation point and again draw the size and shape of what they see as accurately as they can.

Assessment

Have students hold the Draw What You See and Draw What You See with a Magnifying Glass student sheets side by side and compare their drawings of what they saw with and without the magnifying glass.

Have them discuss the following questions:

• Are your two sets of drawings the same or different? If they are different, in what way?

• How did the magnifying glass affect your vision?

• How might people use magnifying glasses in real life?

• What other tools do you know that help people use their senses and bodies better?

Students should be able to conclude from their drawings that the magnifying glass makes objects look bigger. You might want to point out that the word magnify actually means “to make bigger in size,” and mention other related words they might know, such as magnificent and magnitude to reinforce the meaning of “bigness.”

If students are curious about how the magnifying glass works, you could give a simple explanation about how it focuses light rays. A good explanation and drawing for your reference can be found at ThinkQuest: The Optics.

In discussing real-life applications of magnifying glasses, students might mention seeing grandparents or other adults using them to read. If someone brings up using a magnifying glass to start a fire, explain that students should not use the tool in this way, since it is very dangerous.

A discussion of other tools that help people experience and get around in the world might include hearing aids, canes, crutches, and wheel chairs—as well as roller skates, skateboards, bicycles, automobiles, airplanes, and rockets. By the end of the lesson, students should have developed an appreciation of the importance of tools and technology in their lives.

Extensions

This lesson may be supplemented by the related Science NetLinks lesson Scientific Inquiry, which is designed to introduce students to the skills of gathering, recording, and communicating observations.

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(Provided courtesy of Teachers’ Domain, WGBH Educational Foundation and WPSU)

In this series of lessons for grades 6-8, students first experiment with a virtual solar cooker to discover the mathematical relationship among reflection, transmission and absorption. Then they apply their knowledge to building and testing a solar cooker of their own invention. In an extension, students investigate how these principles can be used as sustainable energy sources for homes through passive solar heating.

Content Objectives

Students will know that

• Incident sunlight is reflected, transmitted, and absorbed when it falls upon a surface.
• A solar cooker is a solar collector; it “collects” and traps the sun’s energy, creating heat.
• Solar cookers require three (3) components: glazing, insulation and reflectors.
• There are limitations to how we can maximize solar energy depending upon our geographic location. (For standards, see below*)

Process Objectives

Students will be able to

• Describe how passive solar energy can be used in our everyday lives and homes.
• Discuss the mathematical relationship among reflection, transmission, and absorption: incident solar radiation (I) must equal reflected (R) plus transmitted (T) plus absorbed (A) radiation (I = R + T + A)Predict the relative transmission, reflection, and absorption properties for various materials.
• Construct a solar cooker that fully cooks a food of the students’ choice.

Assessment Strategies

• Observation of students’ interaction with the virtual solar cooker as a pre-instructional tool.
• Evaluation of the completed student handouts, and of the students’ participation in class discussions.

Suggested Time: Two to three (2-3) 50-minute class periods are required for this lesson.

Materials
Part 1:

• Student computers with Internet access
• Virtual Solar Cooker interactive simulation
• Solar Cooking Student Handout PDF Document
• Solar incidence equation lecture notes

Part 2:

Model solar cookers
Cardboard cutting tools
Thermometers or electronic temperature sensor data loggers
Various household/classroom materials for demonstration and cooker components
Mirror
Window glass
Frosted glass
Aluminum foil
Unpainted copper sheeting
Wood
Waxed paper
Clear plastic wrap, sheet protectors or transparencies
Cellophane: clear, yellow, red, blue, green
Construction paper: black, yellow, red, blue, green
Cardboard boxes or foam board
Black paint
Torn-up paper
Scissors
Tape (clear and masking tape)
Rulers/meter sticks
Compass
Thin wooden skewers
Hot dogs or S’mores ingredients
Sunglasses

Multimedia Resources

• Background movie on solar cooking
• Box cooker design plans and FAQ
• Panel cooker design and rationale
• Parabolic cooker examples
• A sun path chart can be made for your town or school at the University of Oregon’s Solar Radiation Monitoring Laboratory using “Sun Chart.”
• Passive design elements

solar box cooker

Figure 1. Diagram of Azimuth Source
Figure 2. Reflection of Light Source

The Lesson

Part I:

Experimenting with a Virtual Solar Cooker (30 minutes)

1. Begin the lesson with a lively discussion that investigates students’ conceptions about radiant energy. Describe what a solar cooker is and spend several minutes eliciting students’

predictions about what types of materials will be best for use in constructing a solar cooker.

2. Allow students to investigate the virtual solar cooker (Virtual Solar Cooker interactive simulation) and prompt them to try to figure out which combination of materials performs the best as a solar cooker. Remind students to make notes about their virtual solar cooker’s performance in Part 1 (Virtual Solar Cooker Wrap-up) of the Solar Cooking Student Handout PDF Document (See above).
3. Discuss the results of investigating the virtual solar cooker with the students. Define transmission, reflection and absorption for the students and introduce the expression, I= T + R + A. Depending upon the level of your students, this may be more of a lecturing activity rather than discussion. Having sample materials to cite examples from the list for Part 2 is suggested.

A suggested demonstration is to throw crumpled pieces of paper at students to illustrate how this is an example of what happens when light strikes a surface (the pieces of paper caught are absorbed, those falling to the floor are transmitted and those bouncing off are reflected.)

4. Have students work in small groups to rank the materials included in Data Table 1 on page 2 of the Cooking Student Handout.

Part II:

5. Share physical models of each of the three types of solar cookers (box, panel, parabolic.) If presenting physical examples is not possible, digital images will work well and the Solarcooking.org website referenced in the Multimedia Resources section of this lesson is a great source. Give a short lecture describing the function of each component of a solar cooker (cover or glazing, insulation, reflector).

Instructions for constructing each type are included in the Additional References section of the Solar Cooking Teacher’s Notes PDF Document.

A short movie link available from The Solar Cooking Archive may also be of interest.

6. Divide the class or allow students to sort themselves into teams of 2 to 3 and set them to work on Part 2 (Select a Solar Cooker and Test Your Predictions) of the Student Handout.

While working through Part 2 each student team needs to decide what type of solar energy collector will best cook the food that they choose. Students may not realize that the cooker cannot reach temperatures much higher than about 300º F, so they may need some coaching away from cooking things like raw meat. They will also need to generate their list of materials based upon their relative properties of transmittance, reflectance and absorbance. An extensive sample materials list is provided in the materials section and the Frequently Asked Questions document from The Solar Cooking Archive. (This may be a useful document to share with students.)

7. Assist students in making connections to the mathematical expression, I = T + R + A in question #3 (Part 2) on page 4 of the Solar Cooking Student Handout.

8. Students will then sketch their solar cooker (question #4 of Part 2 of the Student Handout).

Question #5 prompts them to figure out how to measure the temperatures reached by the solar cooker. If necessary, interject a short lecture on how to collect temperature data, otherwise, allow students to devise their plan and make a data table.

9. Allow students to proceed with construction and testing of their cookers.

10. Once all teams have had an opportunity to test the cookers, allow students to investigate others’ designs and debrief the experience by sharing the data collected for each cooker and analyzing the success of each type of cooker. Students may do questions 6-10 (Solar Cooking Thought Questions) in the Student Handout as part of the in-class wrap-up or for homework.

11. 11. Allow students to explore some of their ideas from question 10 in the Handout.

*Standards: American Association for the Advancement of Science

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(Provided courtesy of the Center for Innovation in Engineering and Science Education, Stevens Institute of Technology)

In this activity for grades 6-12, students design a seawall to protect a major coastal highway from erosion by ocean waves and address these questions: Erosion–can you fight it? How much energy is involved with waves and erosion? Can humans stop erosion of the shoreline? Should we? Is it cost effective?

Procedure

Problem Statement
Your engineering team has been charged to submit a bid for a design for a 600 meter seawall to protect a major coastal highway. Your team must design the wall right at the edge of the water. The structure must be able to withstand the impact of the ocean waves. You cannot spend any more money on the project than is necessary, so it is crucial that the team know what materials can be used in construction and how much each material will cost. It is also important to know that there will be no funding available for beach nourishment (replenishment) in the future. Your team will have to give a 10 minute presentation on the seawall design and submit the bid to the Project Manager (teacher).

1. To determine the amount of wave energy, use an equation to calculate the amount of energy based on the height of a wave. First, determine the amount of energy for every square meter of wave, the energy (joules) is equal to 1260.6 times the square of the wave height.
Wave Energy = 1260.6 (Wave Height)2

2. To determine the Total Energy in a wave, calculate the total surface area of the wave and multiply that by the wave energy.

Total Energy = Wave Energy (surface area of wave)

For example, calculate the energy for an average open water wave that is 2 meters high, 7 meters wide and 500 meters long:

Wave Energy = 1260.6 (Wave Height)2
Wave Energy = 1260.6 (2)m2
Wave Energy = 1260.6 (4)m2
Wave Energy = 5042.4 Joules/m2

Total Energy = Wave Energy (surface area of wave)
Total Energy = Wave Energy (7 meters x 500 meters)
Total Energy = 5042.4 Joules/m2 (3,500m2)
Total Energy = 17,648,400 Joules or 1.76484 x 107 Joules

3. For this activity, the waves will be 8 meters wide, and the section of the seawall that the waves will hit is 300 meters long. Determine the highest water height for this month for this location.

4. Calculate the Total Energy of the wave.

5. Using the table of materials below, your team must design a wall to withstand the wave energy calculated above.

Material Strength Cost/cubic meter Amount needed Total Cost
Natural Rock 30 million joules $50/cubic meter 900 cubic meters
Masonry 40 million joules $150/cubic meter 300 cubic meters
Wood 4 million joules $25/cubic meter 2000 cubic meters
Steel 90 million joules $225/cubic meter 300 cubic meters
Concrete 50 million joules $180/cubic meter 800 cubic meters

Note: The Strength represents how much energy the material can absorb PER WAVE before it structurally fails. The Amount Needed column represents how much material needed to supply the stated strength. For example, a wall of 2,000 cubic meters of wood can absorb a maximum of 4 million joules from each wave that hits it.

6. One of the highest waves in recorded history for this site was 5 meters high. This wave occurred during an exceptionally large storm. Would this information change your design? If so, explain.

7. The following links may be of assistance for research: NOAA pictures of shoreline types; NOAA Beach Nourishment.

8. Using all of this information, create a bid for a design for the seawall project described in the Problem Statement.

Your team must create a 10 minute presentation on the seawall design and submit the bid to the Project Manager (teacher).

When preparing your project, your group might also want to consider if the project will be cost effective, possible alternatives, tourism dollars, etc.

Any mix of materials is allowable, but remember that your bid and presentation will be judged according to:

calculations
structural integrity
projected longevity
aesthetics
environmental concerns
cost

Additional Activity

(Thanks to Christopher Young, a Robert Noyce Teacher Scholar at the University of Rochester)

Erosion Comic Strips: Choose one agent of erosion, and allow students to create a comic strip (handout) that shows the cause of the erosion, the results of the erosion, and the effect this has on humans. (combining art with science, using alternate literacy practices, valuing
creativity)

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