- \n
- 1 tape measure \n
- 1 20' (6 m) length of fishing line (20-50 g weight) \n
- 20 balloons \n
- 1 straw \n
- 10 sheets of blank paper \n
- masking tape \n
- 1 quart-sized plastic storage bag \n

**Rockets** and rocket-propelled **flight** have been in use for more than 2,000 years. People in ancient China used gunpowder to make fireworks and rockets. In the past 300 years, people have gained a** scientific understanding** of how rockets work. Now with advanced technology, **aerospace engineers** make rockets fly farther, faster, higher and more accurately. Our understanding of how rockets work arises from Sir Isaac Newton's three** laws of motion**. It is important for engineers to understand Newton's laws because they not only describe how rockets work, but they also explain how things move and stay in place!

Procedures Overview

\nStudents use an air-powered rocket that travels along a string to learn about Newton's laws of motion. The goal is for groups to propel their rockets as far as possible on a \"tank\" of fuel (in this case, air). In doing this, students determine a relationship between the amount of fuel (air) and the distance the rocket travels.

\nProcedure

\n- \n
- Show students the fishing line. Explain the engineering challenge: To propel a rocket along fishing line that is suspended between two chairs. They have three tries: using a small tank of air, a medium tank of air, and finally, a large tank of air using a single balloon. \n
- Show students the plastic bag, and tell them that their balloon must always fit inside the bag. \n
- Divide the class into student pairs. Give each group a sheet of paper and one balloon. Have students practice blowing up the balloons to determine how much air to add to represent small, medium and large \"tanks\" of air. \n
- Instruct students to blow up their balloons, reminding them that it is sometimes difficult to blow up a balloon the very first time. \n
- While students are blowing up their balloons, thread the fishing line through the straw. Tape the straw to a short side of the plastic bag. (Note: Do NOT tape to either of the long sides.) \n
- Tie one end of the fishing line to a chair; tie the other end of the line to a second chair. (If chairs are not available or do not work well, tape the fishing line to two desk tops, using enough tape to securely hold the line stretched taut.) \n
- Align the bag at one end of the string with the the
*closed*side of the bag towards the center of the string length. \n - When groups are ready to test their rockets, they come to the testing site (the fishing line) one at a time. They test their rockets in the following order: small tank of air, medium and large. \n
- Holding the neck of the blown-up balloon, place it in the storage bag. Let go of the balloon. \n
- Using a tape measure, measure the distance the rocket travels. \n
- On a blank sheet of paper, groups record the distance their rockets traveled, under column headings of
*Small, Medium, Large*--indicating their \"tanks\" of air. \n - If time permits, five minutes before the end time, clean up activity supplies and discuss Newton's three laws of motion: \n

Law #1: Objects at rest will stay at rest, and objects in motion will stay in motion in a straight line unless they are acted upon by an unbalanced force. (law of inertia)

\nLaw #2: Force is equal to mass multiplied by acceleration *( F = ma).*

Law #3: For every action, there is always an opposite and equal reaction.

", "Attachments": [], "WrapUp": "- \n
- What propelled your rocket along the string? \n
- What would happen to your rocket if you launched it without it being attached to the string? \n
- How would having the fishing line at an incline affect the performance of your rocket? \n
*For older students:*How was each of Newton's three laws demonstrated in this activity? \n

- ruler
- 4 paper cups
- marker
- paper
- scissors
- pencil, with eraser end
- push pin
- stapler/staples
- miscellaneous cardboard pieces

An **anemometer** is an instrument that measures **wind speed**. Knowing wind speed is important in a variety of situations: at airports (this real-time data helps pilots fly safely); for weather prediction (data is collected on sea buoys, marine vessels, ports and land in order to inform the public); for public safety and efficiency (railroads install wind alarms that report route conditions because high wind gusts cause loss of train power and derailments, and can blow over empty freight cars). Wind alarms also **monitor **conditions near industrial cranes, exposed roofs or other situations in which high winds can be hazardous. Engineers use data collected from anemometers to design and plan the location of **wind turbines** (huge windmill-like devices that collect wind as an energy source). The direction and strength of the wind is dependent on local terrain, height and other factors. Anemometers can tell us where the wind is the strongest in a specific area. Today, students build and use anemometers to determine the best place for a wind turbine.

Procedures Overview

Students work in pairs to build anemometers and use them to measure wind speed. Then they take measurements in various locations outside to determine the best place for a wind turbine. \r\n\t\t\t\t

Procedure

- Divide the class into student pairs and hand out supplies.
- Instruct groups to color the outside of one of their cups. This is the cup students watch so that they can count the number of rotations their anemometer makes.\r\n
- Have students cut two equally sized strips of cardboard: around 1 in. (2.5 cm) wide x 10-12 in. (25-30 cm) long.\r\n
- Instruct students to place their two strips of cardboard perpendicular to each other, forming a plus sign; use a ruler to find and mark the center of each strip and overlay the two centers so that their anemometer is
**symmetrical**. Then, have them carefully staple the strips together near the center of the strip (tell them*not*to put a staple directly in the center). This makes the anemometer frame. - Next, students staple a cup, turned sideways, to each end of the frame, making sure the cups all face the same direction (see the image).\r\n
- Have students press the push pin through the
*center*of the frame and into the pencil eraser (see the image).\r\n - Students test their anemometers by blowing on the cups to see if they turn easily. \r\n

Measuring Air Speed

- Have each team pick five places outside that they want to test. (Note: It is okay if multiple groups pick the same location; avoid areas that are protected from wind, such as covered entries and under picnic tables.)\r\n
- Take students outside and tell the groups to count the number of times their anemometers rotates in 30 seconds.
- Assign roles: One person in each group is the
*Counter,*who counts 30 seconds by using the method of saying: 1 one-thousand, 2 one-thousand, 3 one-thousand, etc. The other person is the*Recorder,*who counts and records the number of rotations of the cups.\r\n - Tell students that after they move to one of their selected spots, the Counter holds the anemometer high and begins counting after saying "3, 2, 1, go!" The Recorder counts the rotations by watching the colored cup as it spins by. After 30 seconds, students stop counting and the Recorder reports the total number of rotations.\r\n
- On a blank sheet of paper, the Recorder writes the number 1 (for the first anemometer location), and writes the number of rotations made by the anemometer.\r\n
- Have groups move to their next selected locations and repeat the above steps two times. They conduct the above steps for each of their remaining locations.\r\n
- After all of the recordings, return to the classroom. Have students multiply their rotations by 2 to get the total rotations per minute.\r\n
- Have students compare and discuss their results. If time permits, have them draw a map of the outside area on the classroom board with wind speeds noted, so as to determine the locations where the wind speeds are the fastest. \r\n

- Did any of your classmates record the wind speed in the same place as your group? Did they get the same results? Why or why not?
- Looking at the results, where would be the best place to locate a wind turbine? Why or why not?
- Did some anemometers work better than others? What was different about them?

Each group needs:

\n- \n
- 20 plastic drinking straws \n
- masking tape \n
- scissors \n
- 1 sheet of paper \n
- pencil or marker \n

For the class to share:

\n- \n
- measuring stick or ruler \n
- various hardcover and softcover books to use as weights \n
- 2 desks or tables of equal height from the floor, to serve as the testing station \n
- scale, one that can weigh a minimum of 3 lbs. (~1.4 kg) \n

The most common type of bridge is a **beam bridge**—a structure made of horizontal, rigid beams whose ends rest on two columns. The **load** of the bridge is supported by the **columns**. Load refers to the bridge’s own weight that needs to be supported, as well as any weight that is added to the bridge such as cars, trucks and people. A **truss bridge** is a type of beam bridge that has **triangular** units to distribute the load and support the bridge.

Overview

\nYour engineering challenge is to design and build a bridge that can span a gap while holding as much weight as possible. Your materials are straws and tape, and your bridge must meet the design constraints.

\nBridge Design and Construction

\n- \n
- Organize the students into groups of three. \n
- Hand out paper and a writing utensil to each group. \n
- Show students some images of truss bridges (or show the images provided in this write-up). \n
- Inform students of the following design constraints: \n

- \n
- bridge must be at least 10 inches (25 cm) in length and able to span an 8-inch (20-cm) gap \n
- bridge must be able to securely hold gradually added weight placed in its center until it fails (begins to bend) \n
- bridge must incorporate a truss design \n
- bridge must be made of 20 (or fewer) straws \n
- groups may not receive any replacement straws \n
- bridge may not be taped to the desk \n

- \n

- \n
- Direct groups to brainstorm design ideas for their bridges and record and sketch their ideas on the paper (5-7 minutes). Advise students to carefully plan out their bridges before cutting the straws since they will not receive any replacement materials. \n
- After every group member has presented his/her ideas, have groups each decide on one bridge to build. \n
- Give teams 30 minutes to create their bridges. \n
**Tip:**It may be difficult for small hands to figure out the taping of straws that are at add odd angles to each other. Circulate the room to assist students with any construction challenges they encounter. \n

Bridge Testing

\n- \n
- Make a testing station by placing two desks (or tables) approximately 8 inches (20 cm) apart. \n
- One-by-one, help each group test its bridge: \n

- \n
- Place the bridge across the gap between the two desks, positioning it with equal lengths of bridge ends resting on each desk (see Figure 1). \n
- Slowly place one book on top of the bridge. \n
- Continue to add books until the bridge fails or noticeably begins to bend (do not add so much weight that the bridges are ruined). \n

- \n

- \n
- Direct students to weigh the books that were successfully supported before the bridge collapsed. This means removing from the stack of books the last book, the one that caused the bridge to collapse. \n
- Write the group’s total weight on the classroom board. \n

- \n

- \n
- If time permits, have students make improvements to their bridges and retest. \n
- As a class, examine the class data, and ask and discuss the Thought Questions. \n

- \n
- Which bridge design held the most weight? \n
- Which part of your bridge gave out first? Why? \n
- How would you improve your bridge design? \n
- How would you change your design if you had to span a 20-inch (51-cm) gap using the same materials? \n

Each group needs:

\n- \n
- 1 sheet of paper \n
- 1 writing utensil \n
- 1 small DC motor \n
- 1 rubber band \n
- scotch tape \n
- stiff ruler \n
- cylindrical-shaped cork, at least 2 cm or ¾-inch in diameter \n
- 4 paperclips \n
- 4 index cards \n
- scissors \n

For the class to share:

\n- \n
- alligator clips \n
- DC voltmeter \n
- hair dryer or electric fan (wind source) \n

Engineers design **wind turbines** to transform wind energy into electrical energy, providing a **renewable** and economical alternative to conventional power plants in some locations. Wind is considered a clean energy source because wind turbines do not cause air or water pollution since no fuel is burned.

Overview

\nStudents build small wind turbines to generate the maximum amount of voltage from a constant wind source.

\nProcedure

\n- \n
- Ask students what they know about wind energy and wind turbines. Then present and discuss the Introduction content. \n
- Organize the students into groups of two. \n
- Direct the teams to discuss factors they think would affect the performance of a wind turbine (such as wind strength, direction and elevation; animals, etc.). Then, briefly have each group share its thoughts with the class. \n
- Tell students that their engineering challenge is to build wind turbines that generate the most electrical energy. While the motor setup is the same for all groups, teams can design and build the propellers however they wish. \n

- \n
- Demonstrate the motor setup to the class (as follows, see Figure 1). \n

- \n
- Use a rubber band to securely attach the motor to one end of the ruler, leaving the motor shaft sticking over the end of the ruler \n
- Adjust the voltmeter settings so that the rotating dial is on 20V, the black wire comes out of the COM port, and the red wire comes out of the VOMA port. Use alligator clips to connect the voltmeter to the motor. \n
- Push the cork onto the motor shaft. \n
- Turn the cork and show students that turning the cork causes a voltage reading to appear on the voltmeter. \n

- \n

- \n
- Show students the hair dryer (or fan) that serves as the wind source. Remind them that the engineering challenge is to generate as much electrical energy as possible—that is, the highest possible voltage reading on the voltmeter. \n
- Show each group the supplies available to use for their propeller designs: 4 paperclips, 4 index cards, scissors, and tape. \n
- Give each group a pen/pencil and a piece of paper. \n
- Direct the teams to brainstorm ideas for how they want to build their propellers, and sketch all generated ideas.As students brainstorm (3-5 minutes), pass out the supplies to each group. \n
- While students are building their propellers, set up a classroom testing station, such as a desk where students can place their turbines so that the propellers hang off the desk edge. \n
- When students are ready to test their designs, hold the hair dryer (or place the fan) about a foot away from the turbine. Have one teammate hold the turbine in place while the other monitors the voltmeter, taking note of the highest voltage reading. Have students record all their results (voltmeter measurements) on the back of their design papers (Test 1, Test 2, Test 3, etc.). \n
- Give students 20 minutes to test and modify their turbines. Then have each group approach the testing station and conduct a final test with its best design effort. The turbine propeller design that obtains the highest voltage reading is the winning team. \n

- \n
- Which design(s) worked the best? Why? \n
- Would these designs have worked if the wind was coming from a different direction? \n

Each group needs:

\n- \n
- poster board, 24 x 24 inches (60 x 60 cm) \n
- large paper plate \n
- small paper plate \n
- 2 pencils \n
- scissors \n
- dark-colored marker \n
- 2 rubber bands \n
- stopwatch \n
- piece of paper \n
- 12 pennies or washers \n
- masking tape, 3 or 4 12-inch (30-cm) lengths \n

Engineers need to understand the concepts associated with **circular motion** and **angular momentum** as they design equipment, systems and products with spinning components. **Aerospace engineers** design satellites to spin as they orbit around the Earth so that they do not tumble out of control. **Automotive** **engineers** design car parts to spin in specific ways so that they do not come apart at high speeds. **Mechanical engineers** design generators, washers, dryers, fans and other machines so that they are **balanced** as they spin. Even a forward pass in a football game is more effective and stable when the ball is thrown with the ideal spin.

Overview

\nStudents build and experiment with different spinner designs to determine which design features create the most effective spinners.

\nProcedure

\n- \n
- Present and discuss the introduction content with students. Ask them to come up with a few more examples of engineering designs in which rotation is important. (If students are stumped, prompt them with examples such as wind turbines/blades, amusement park rides, spinning computer and mechanical parts, etc.). \n
- Ask students if any of them ever played with spinners or tops when they were younger. Review how spinners work (you grasp the spinner so its point is down and give it a good twirl with your hand and wrist) and what features spinners have in common (a point on the bottom to spin on, a place at the top to grasp it to spin, a specific shape [round], etc.). \n
- Organize students into groups of two and hand out the supplies. \n
- Direct students on how to make and test a spinner: \n

- \n
- Trace one of the paper plates onto the poster board with a pencil, and cut out the drawn circle. \n
- Use a dark-colored marker to draw a large dot at any point along the circle. (Later, this dot will help us count how many times the spinner goes around.) \n
- Poke a pencil into the middle of the poster board circle (refer to Figure 1), leaving at least part of the pencil poked through. Then, secure the circle firmly in place by wrapping rubber bands around the pencil, one above and one below the paper circle. \n
- Practice spinning the spinner on the pencil tip. Watch the colored dot to count the number of rotations the spinner makes. \n
- Using a stopwatch, have groups spin their spinners for 10 seconds, recording on paper the number of spins. \n
- Run at least three trials with the spinner to get an average spin value. \n

- \n

- \n
- Next, repeat step 4, trying many variations, such as: \n

- \n
- Moving the circle up several inches higher on the pencil. \n
- Making a new circle and pushing the pencil through the circle at a point away from its center. \n
- Taping six pennies or washers on the circle (balanced or not—let students figure out if balancing makes a difference). \n

- \n

- \n
- With what they have learned from the previous spinners and tests, have groups make new spinners with the engineering challenge to create a spinner that makes the most spins in 10 seconds. \n
- Encourage students to perform many trials, adjusting the following: \n

- \n
- Size/shape of the poster board \n
- Height of the circle on the pencil \n
- Location of pennies/washers on the poster board \n
- How fast they spin the pencil \n

- \n

- \n
- As a class, have teams describe their final spinner designs, including the number of spins they were able to achieve in 10 seconds, as well as why they think their spinner designs did/did not work well. \n

- \n
- Which design(s) worked the best? Why? \n
- Which design(s) did not work? Why not? \n
- How might changing the pencil length affect your results? \n

Each group needs:

- 2 sheets of graph paper
- 14 Necco™ wafers
- empty soda can
- 1 hardback book
- 1 digital scale (to be shared)

What is pressure? **Pressure** is defined as the amount of **force** applied per unit area or as the **ratio** of force to area (P = F/A). The pressure an object exerts can be calculated if its **weight** (the force of **gravity** on an object) and the contact surface area are known. For a given force (or weight), the pressure it applies increases as the contact area decreases. Engineers must understand air pressure because it affects the way in which **air pollution** travels through the air. Especially in highly populated areas, engineers work with local communities to understand their unique weather and atmospheric conditions, and suggest changes to keep the air quality at a safe level for breathing. They also create new prevention technologies that address air pollution at the **source**. \r\n\t\t\t\t

Procedures Overview

Students develop an understanding of air pressure by using candy wafers to model altitude changes and by comparing its magnitude to gravitational force per unit area. Students also observe changes in pressure with an aluminum can experiment.

Pressure

- Divide the class into teams of two students each.
- Pass out the books, graph paper and soda cans to groups.
- Ask students to hold a book flat on their hands. Then, ask them to try to balance the side of the book on their palms. Ask them which way of holding the book seems to be heavier, or pushes more on their hands. (The side should seem heavier.)
- Have students, one group at a time, take their book and weigh it on the scale while laying flat. Then, have them turn it on its smallest side and weigh it. Ask students why the book weighs the same, but seems to push more on their hands when they are balancing it on its side. Explain to them that this is pressure (force per area).
- Instruct students to record the weight of their books on their graph paper.
- Students next calculate the pressure for the two configurations of the book. To do this, they outline the book on a sheet of graph paper in each configuration (flat and on its side).
- Then they calculate the area by counting the squares on the graph paper. Then they divide the weight of the book by the area, which gives them the pressure the book is exerting on the table/paper in pounds per square inch (psi). (Tip: It may help to provide an example on the board and/or help students with the division.)
- To understand this, students should see an example of how spreading weight decreases the pressure on an object. Have groups balance their book on top of an empty can. Then, have them carefully stand on the book, keeping their weight centered over the can (their teammates can help them balance by holding their hands). The empty can should support their weight.
- Now, have students remove the book and try to stand on the can—the can should crumple under this higher pressure (pressure that is not distributed).

Pressure and Altitude

- Ask students if/how they think air pressure changes with altitude. (Yes, it decreases as altitude increases.)
- Hand out Necco wafers to students and have each group make a stack of all their wafers. Explain that air pressure in Washington, DC (sea level) is ~14.7 psi, while in Denver, CO, it is ~12.4 psi. Use the wafers to demonstrate that the table under the bottom wafer (with 14 wafers on top), it is the equivalent of sea level.
- Have them point out where Denver would be in their model of the atmosphere (that is, in their stack of Necco wafers).
- Ask students to describe in their own words how air pressure changes with altitude. (The air pressure at sea level is the highest, because at that point all the air [wafers] is pressing on everything. So, as you go up in altitude, the air pressure is less.)
- Have students help clean up the wafers by eating them.

- What makes up the pressure we feel from the air? Why doesn't this pressure crush us?
- In terms of pressure, explain why sharp knives cut better then dull ones.