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### Matter and Energy: Air Mail Challenge

#### by Girlstart

The Engineering Design Process is a process that helps engineers solve everyday problems. In this activity, kids concentrate on the third step in the process – designing a prototype. Kids design containers that can carry a fragile package. The container must be lightweight, water proof, buoyant and protect the fragile package inside.

Engineers design and build structures of all types, and as the girls in Girlstart’s After School Program, Club Girlstart, learned matter and energy are important factors to consider in the Design Process. Girls created protective containers out of cups and cotton balls to transport their fragile cargo - a potato chip!

Overview:
Students test and compare the mass and the ability to sink and float of different materials to determine the best material to use in a building a container. Students test the ability of different materials to withstand the force of being dropped on the ground to determine which material will protect a fragile item the best. Students will use the results of their tests to build a prototype of a container that can protect a fragile item when dropped on the ground or in water.

Objectives:

 (5.5A) Classify matter based on physical properties, including mass, magnetism, physical state (solid, liquid, and gas), relative density (sinking and floating), solubility in water, and the ability to conduct or insulate thermal energy or electric energy. (5.2) Scientific investigation and reasoning. The student uses scientific methods during laboratory and outdoor investigations. (4.5A) Measure, compare, and contrast physical properties of matter, including size, mass, volume, states (solid, liquid, and gas), temperature, magnetism, and the ability to sink or float. (4.2) Scientific investigation and reasoning. The student uses scientific inquiry methods during laboratory and outdoor investigations.

Materials:
• Engineer’s Journal
• duct tape
• Pringle’s potato chips or generic brand - several per group
• bubble wrap, cotton balls, and/or packing peanuts
• balance (triple beam or pan balance with weights) – one per group
• plastic cup (9 oz.) – two per group
• foam cup (8.5 oz.; 9 oz. if possible) – two per group
• paper cup (9 oz.) – two per group
• tub of water - one per group; groups may also share
• butcher paper or plastic tarp – one per group
Air Mail Challenge Testing and Results page – 1 per student
Manufacturing Engineer poster
Air Mail Challenge Directions – transparency and/or 1 copy per group
Vocabulary Match – 1 set per group

Vocabulary:

 balance A tool used to measure something’s mass buoyancy The ability of an object to float in a liquid or gas density The property of matter that compares the amount of matter to the space it takes up mass The amount of matter something contains physical properties The characteristics of a substance that can be observed or measured without changing the substance prototype The original model on which a product is based or formed volume The amount of space that an object or substance takes up

Preparation:
• Make a color copy of the Manufacturing Engineer poster.
• Make transparency and copies of Air Mail Challenge Directions.
• Make copies of the Air Mail Challenge Testing and Results page for each student.
• Place butcher paper or plastic tarp over the areas where students will be testing their containers for buoyancy. Fill containers with water for the sink or float test. Provide one for each group or let groups share.
• Make one set of the Vocabulary Match for each group. Cut out the cards and place in plastic bags.

Careers
Manufacturing engineers make things. They design, direct and coordinate the processes and systems for making almost any kind of product – from beginning to end. Manufacturing engineers apply scientific principles in designing and producing quality products. This includes finding ways to improve what they make and packaging planning.

Engage:
1. Show students the design challenge transparency. Explain that they are engineers today, and they have a challenge to complete.

You are a team of manufacturing engineers assigned the challenge of designing a package with the least mass that can be used to transport fragile items from your location to scientists studying a rare animal species on a remote island in the Pacific Ocean. Your package will be flown to the island and dropped from a low altitude to the scientists on the land. Your task is to design, build, and test a prototype of the container. You will use a potato chip to test how well the container can protect a fragile item. Because the container will be dropped from an airplane, the container must withstand the forces and conditions of landing in the water or on land. Your container must also meet the specifications below.

The container must:
• have the lowest mass possible without going over 20 g.
• float on water
• be waterproof
• protect the potato chip from breaking

2. Show students a Pringle’s potato chip. Ask them to describe its physical features such as thin, curved, rough, salty, and crunchy.

3. Hold the potato chip next to your hip and let it drop to the floor. Students describe the potato chip now. For the most dramatic results, hold the chip on its side before dropping it. Ask:

• How have the physical properties, or characteristics, changed? The chip is in smaller pieces and it has different shapes.
• Which physical properties are the same? The chip is still thin, salty, rough, and crunchy.

4. The potato chip represents the fragile items that the airplane will be carrying and dropping down to the scientists on the island. Ask:

• How can you design a container to protect it?
• What qualities must the container have? It must be buoyant and have the ability to float. It must be water proof and withstand the force of hitting the hard ground.

Explore:
1. Explain to students that they will test different materials before deciding which ones to use for their container. Take a quick survey of students to see which materials they would choose for their containers if they had to choose now. Ask the same question after students have conducted their tests to see if they change their thinking.
2. Organize students into groups. Give each group the following materials: plastic cup, foam cup, paper cup, and balance. Point out that each cup has a volume of about 9 oz. this helps create a fair and equal test.
3. Give each student the Air Mail Challenge Testing and Results page to use in recording data.

 mass sink or float Drop test foam cup plastic cup paper cup

4. Conduct the mass test.

• Each group will use the balance to find the mass of each material. Ask:

o What is mass? Mass is the amount of matter that something is made of.
o How do we measure mass? We use a pan or triple-beam balance to measure mass.
o What has more mass, a ping pong ball or a golf ball? The ping pong ball is filled with air, but a golf ball is solid. The golf ball contains more matter, so it has more mass.
o Which cups do you think have the most and least mass? Answers will vary.

• Take a few minutes to review how to use the balance. Ask all groups to measure the mass of a selected cup. Then compare each group’s answer. If a group is off more than several grams, work with them to make sure they are using the balance accurately.
• Students may then find the mass of the remaining cups, and record their answers.

Example:

 mass sink or float Drop test foam cup 2 g plastic cup 9 g paper cup 5 g

5. Conduct the sink or float test.

• Discuss what students think each cup will do when it is placed in water? Ask:

o Why do some things float? Objects that are denser than water will sink. Objects that are less dense than water will float.
o What is density? Density is the amount of matter something has in a given amount of space. If you compare the same amount of water and foam, the water will be denser than the foam. Therefore, the foam will float.

• What does it mean for something to be buoyant? Things that are buoyant float.
• Students place each cup in the water and observe for several seconds. Allow the cups to fill half way with water to compare whether they will sink or float. Students record observations in their data chart.

Example:

 Mass Test Sink of Float Test Drop test foam cup 2 g Does not sink when filled half way with water plastic cup 9 g Does not sink when filled half way with water paper cup 5 g Sinks when filled half way with water

6. Conduct the drop test.

• Explain that students must test to see which material they think will best protect the potato chip when dropped.
• Give each group an additional foam, plastic, and paper cup. Also give groups three potato chips and duct tape. Students will place a chip inside each type of cup and then attach a second cup.
• Demonstrate how to tape the cups together with the chip inside.
• To conduct the drop test students will select one of their containers and hold it at hip level. Students will let the container drop from their hands. Students will gently open the container to see what the chip looks like. Students will record the results.
• Students will conduct the test with each container.

Example:

 Mass Test Sink or Float Test Drop test foam cup 2 g Does not sink when filled half way with water Potato chip did not break plastic cup 9 g Does not sink when filled half way with water Potato chip did not break paper cup 5 g Sinks when filled half way with water Two small pieces broke off.

Explain:
1. Students share their results and discuss which materials they think would make the best containers. Students explain evidence to support their conclusions. Ask?

• What surprised you about the mass of each material? Answers will vary. Students may be surprised with how low of a mass the foam actually has. Explain that even though the foam is thick, it is made up of a large amount of air.
• How well did each cup float? Answers will vary. All the cups float but will sink differently depending on the amount of water that leaks inside.
• Were any cups more buoyant than others? Answers will vary.
• How will you decide which material to use? Answers will vary. Students may decide on foam since it has the lowest mass.
• Why do some materials protect the chip better than others? Some of the materials don’t absorb the force of hitting the floor very well, and the chip may hit the sides of the container hard enough to break. Other materials cushion the chip as it hits the floor, reducing the amount of force applied to the chip.

2. Students discuss with their groups which material they will use for their prototype. Using the results of their testing, each group will explain their choice and the evidence they used in their decision.

Elaborate:
1. Review the requirements of the challenge. Students must design, test, and build a container that will hold and protect the potato chip when dropped from hip and shoulder heights. Containers must be able to stay afloat for at least 30 seconds without allowing water to leak inside. Containers must not exceed 20 g.
2. Based on the data, each group will select the material they think will make the best container for their potato chip. Ask:
• How can you modify your design to ensure the safety of the chip? Students may suggest packing something in the container to help absorb the force of being dropped.
3. Students should discuss other materials they would like to add to ensure the protection of their chip such as cotton balls, packing foam, and bubble wrap.
4. Students modify their designs, predict the overall mass of their new container, and then construct their prototype. Ask:
• How can you protect your chip while making sure the container has the lowest mass possible and does not go over 20 g? Students will have to make some choices about how much packing to include. If they put in as much as possible their container will have too much mass.

 Steps Explain Example Use the selected materials to construct the container. Adding packing materials and duct tape will add to the overall mass. Students must also be careful that materials to do not apply pressure the chip and break it. Students must also be careful in attaching the cups together. If not taped carefully, water will seep into the cup and ruin the chip. Use the selected materials to construct the container. Remember the following: Adding packing materials and duct tape will add to the overall mass. Handle the container carefully to prevent the chip from breaking. Create an airtight seal when attaching the cups together to prevent water from leaking inside. Students test their containers in a tub of water to make sure it can float and will be water proof. Students should test the container for 30 seconds to determine if their design works. Test your group’s container in the tub of water to make sure it can float and will be water proof. Test the container for 30 seconds to determine if the design works. Students conduct the drop test from their knees and then from their shoulders to determine if the container provides enough protection. Students make necessary modifications. Students measure the final mass of their containers. It cannot be greater than 20 g. Conduct the drop test from your knees and then from your shoulders to determine if the container provides enough protection. Then make necessary modifications. Be sure to measure the final mass of your group’s container. It cannot be greater than 20 g.

Evaluate:
1. Each group will demonstrate their container to the class by performing the drop test and sink or float test. Make a class record on the board to show each container’s mass and testing results.
2. Students conduct the drop test. Ask:

• How did you modify your container to protect the potato chip? Answers will vary.
• How did this affect the mass of the container? Adding material increases the mass.

3. Conduct the sink or float test to see how well the container floats. Ask:

• How did you modify your design to make sure the container would float and remain water proof? Answers will vary.
• How did your modifications affect the mass of the container? The more tape you add, the greater the mass of the container.

4. Compare each group’s design and overall mass. Compare how the container with the least mass was able to meet the requirements of the task. Ask:

• What surprised you while conducting this challenge? Answers will vary.

5. Students complete the reflection in their Engineer’s Journal.
6. Students complete the vocabulary math if time.

Options:
1. See how high students can drop their containers without breaking the chip.
2. See how many chips students can pack in their container without any breaking.
3. Each group may earn a score based on how much their chip breaks in the test:

• 50 points – no breaks
• 25 points – cracked but in one piece
• 10 points – broken in two pieces
• 5 points - broken in three pieces
• 2 points – broken in four or more pieces

Resources:
TryEngineering: Ship the Chip
http://www.tryengineering.org/lessons/shipthechip.pdf

___________________________
Girlstart is an award-winning Austin-based non-profit organization dedicated to empowering girls in science, technology, engineering, and math (STEM).

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The views expressed are those of the author and are not necessarily those of Science Friday.

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