Leaning Tower of Pasta	Build a skyscraper using marshmallows and pasta.
Egg Pitching	Find ways to throw eggs at high speed and not have them break. This exercise shows how car safety belts and air bags can save lives.
Go Fish	Make an electromagnetic fishing pole to catch fish with magnetic personalities!
Geodesic Dome	Build a domed clubhouse using newspaper and see how strong it is.
Product Dissection	Learn what makes things work by taking them apart.
Filtering	Discover how water filtration works and have fun at the same time.
Rocket Transportation	Construct a balloon rocket and use it to carry a paper clip payload.
Homemade Slime	Create a fluid that consists of a very large molecule.

Leaning Tower of Pasta

Canada is home to the tallest free-standing tower in the world: the CN Tower. You probably won't be able to match its 533 metres, but let's see just how sky-high you can get this structure.

Materials:

• spaghetti (uncooked!)

• marshmallows (small)

• measuring tape

• all kinds of balls

Instructions:

There are no step-by-step instructions for this project! You can do whatever you want with the materials. The object is to build a tower as high and as strong as you can using only spaghetti and marshmallows. How much weight will your tower support? Will it hold a ping-pong ball? A golf ball? A tennis ball? A basketball? A cannon ball? Give yourself points as follows:

If your structure holds:

a...	you get...
cannon ball	50
basketball	20
tennis ball	10
golf ball	7
ping-pong ball	5

• Give yourself 1 point for every centimetre of tower height.

• Give yourself an extra 5 points if you finished your tower before you ate all the marshmallows.
  

• Give yourself 5 extra points if your tower is "funky" looking (you'll have to be the judge of this one).
  

• Give yourself 5 extra points if your tower makes your teacher do a "double-take".

• If your tower is able to hold more than one object, you get the points for both.

Ratings
46 and up: You were born to build. You can work on my tree house anytime!
33 to 46: Not bad! With a bit of duct tape, you'll make a first-rate builder.
20 to 33: You'll do. Just don't stand too long under anything you build yourself!
up to 20: Look out! Crash and burn time! Try again, and don't eat all your building supplies this time.

Additional Challenges:

Why not get together with some friends and have a tower-building contest? You can make all kinds of categories: tallest tower, most wind-resistant tower (blow really hard or use a hair dryer), strangest-looking tower, most marshmallow-loaded tower, etc.

Experiment with your materials. Are marshmallows stronger in tension or in compression? What about spaghetti?

Skyscrapers and towers can sway back and forth more than a metre on windy days. High winds can cause motion sickness in people working on the top floors. To brace structures against the wind, engineers design skyscrapers with reinforced cores or stiff external skeletons. Tuned dynamic dampers can also lessen the effects of wind. The huge dampers, which weigh hundreds of tons, offset the wind's force by sliding in the opposite direction to the building. Get out a hair dryer and find out how much wind your tower can take.

Reprinted with permission of YES Mag.

Egg Pitching - learning about seat belts and air bags

Design ways to cushion an egg that is thrown through the air. Using the theories behind air bags in automobiles, find the best way to protect it from impact so you can throw it faster and further.

Discussion

Moving objects have momentum. Newton's First Law of Motion says that unless an outside force acts on an object, the object will continue to move at its present speed and direction. Automobiles consist of several objects, including the vehicle itself, the passengers inside and any other loose objects in the vehicle. Unless the objects inside the car are restrained they will continue moving at whatever speed the car is travelling even if the car is stopped by a crash.

Changing or stopping an object's momentum requires a force acting over a period of time. If momentum changes instantly, as in a car crash, the force is very, very great! If the momentum can be changed over a period of time, even a fraction of a second, much less force needs to be applied with less damage or injury.

In a head-on collision, if a passenger flies into the dashboard of a car, their momentum is instantly stopped, and serious injury is often the result. If the passenger is restrained by a seatbelt, their momentum is reduced more gradually by the constant and smaller force of the belt acting over a longer period of time. Seatbelts can reduce the impact to a passenger to one-fifth of the impact suffered by the body of the car.

Passive restraint laws, combined with an interest in air bags have made vehicle safety a selling feature on automobiles. An air bag is made of a coated fabric and is stored in a module mounted on the steering wheel. Crash sensors, which activate upon impact at speeds of 10-15 miles per hour, are mounted in several locations on the car chassis.

In a crash, the sensors ignite a chemical, sodium azide, which releases harmless nitrogen gas to instantly inflate the bag. As the driver or passenger is thrown into the bag, it applies a restraining force. Even though this entire process happens in only 1/25th of a second, the added time is enough to prevent serious injury.

Air bags are not intended to replace seat belts. They are part of a supplemental restraint system. Seat belts are still necessary because air bags only work in front-end collisions of more than 10 miles per hour. Only a seat belt can help in side impacts, rear-end collisions, side swipes and secondary impacts.

Here are some things to talk about:

How does an air bag resemble a parachute? How is it different?
Is it possible to invent a springy car that would absorb the impact of accidents by itself?
Why can't air bags help when a car is rear-ended?

Materials:

• four to six raw eggs
• flat bed sheet (twin size works best!)
• two broom stick handles or dowels
• needle
• thread

Turn under the bottom edge of the sheet about 10 cm. Sew the flap up and insert the broom stick handles into the top cuff and the one you have just sewn.

Have four classmates hold the corners of the sheet out horizontal to the ground.
Have a fifth student take aim, wind up and pitch the egg up and over onto the sheet.

Experiment with different speeds and distances to see how far and how fast you can throw the egg without breaking it.

Discussion:

What happens to the egg's momentum? What would happen if you were dropping the egg on a concrete floor?

How could you cushion the egg itself? Would that transfer the momentum of the egg?

Would a parachute attached to the egg provide enough cushion to keep it from breaking? How high could you drop an egg attached to a parachute?

Does the size of the sheet make a difference in your experiments? What if you pulled the sheet taut?

See if you can find other examples of impact protection devices. Where are they most common? Why do you use pads for gymnastics? What about helmets and knee pads? Do they transfer momentum?

Courtesy of Newton's Apple

Go Fish

You can build an electromagnetic fishing pole and catch some fish with magnetic personalities!

Discussion:

Engineers use magnets in motors, audio speakers and medical equipment, just to name a few uses.
Magnets are useful because they generate a force called a magnetic field. You've seen the effect of a magnetic field when watching a magnet attract, or pull, an object.

Magnets have a north and a south pole. The same kind of poles push each other apart and different poles attract or pull each other together.

Metals are made up of groups of atoms. If these groups are lined up in the right way, a magnetic field is produced.

Electricity flowing through a wire has the ability to line up the groups of atoms in metals, creating a magnetic field, and turning the metal into an electromagnet.

In this activity, students will make an electromagnet with wood and wires. The more times the wire is wrapped around the nail, the stronger the magnetic field becomes. An electromagnet acts just like a permanent magnet except an electromagnet is turned on and off by starting or stopping the flow of electricity through the wire.

Materials:

• piece of wood 12" long, 1/2" x 3/4"
• two wires (41" and 2") with the ends stripped: one end stripped to 1" and the other to 1/2"
• one 2 1/2" nail
• D-size battery
• electrical tape
• two 1/2"-screws
• paper clips

Instructions:

Put two screws into the wood, one 3" and one 4" from one end. Leave about 1/4" of each screw exposed. Drill a hole 1/2" from the opposite end. The hole should allow two wires to pass through.

Place the battery on the wood, near the screws. Fasten the battery to the wood using the electrical tape.

Leave 7" of wire from the short stripped end of the wire. Start wrapping the wire tightly around the nail, starting from the head of the nail. Stop wrapping the wire around the nail when about 13" of wire is left to the long stripped end of the wire.

Pull the 7" long piece of wire through the hole. Tape the bare wire to the battery.

Pull the 13" end of the wire through the hole. Wrap the bare end of the wire, starting at the yellow insulation, around the bottom-most screw twice. Make a loop at the end of the bare piece of wire. Wrap the small wire around the top screw twice then tape the other end to the battery. Touching and holding the loop to the top-most screw will cause electricity to flow through the wire. Make sure the connections to the battery are good.

Scatter the paper clips, grab your fishing pole and go fish!

Courtesy of National Engineers Week (U.S.)

Geodesic Club House

The word geodesic comes from two Greek words which mean "earth dividing". Geodesic domes are made of interlocking geometric shapes-often triangles. Because loads are spread over many triangles, these domes are especially strong. Often made of aluminum bars and plexiglass, they're also light compared to ordinary domes.

Geodesic domes were popularized by an American inventor named Buckminster Fuller (1895-1983). Look for the distinctive Bucky-ball shape in museums, greenhouses, alternative housing, and science centres.

Materials:

• newspaper

• doweling or broom handle

• tape

• marker pen

• stapler (and staples)

• measuring tape

Note

Like a real engineer, you will probably need to rely on teamwork to get this project finished. Why? Because the dome tends to flop over unless it's supported, and stapling is a bit tricky unless you get help holding all the newspaper tubes together.

Using a piece of doweling makes stronger tubes that are harder to staple. Using a broom handle makes slightly weaker tubes that are easier to staple.

Instructions:

Making the beams (Note: to save time, the beams can be prepared before the classroom visit.)

Open up a sheet of newspaper. Roll the newspaper around the doweling diagonally from one corner to the other.

Cut a piece of tape and stick it to something (preferably not your head) for a minute. Hold the newspaper tube in one hand and gently pull out the dowel with your other hand. If you rolled the newspaper really tightly, you may need to wiggle and twist the dowel a bit. Use the piece of tape to keep the newspaper tube together.

Cut the tube to length. (Note: The ends of the tube are not very stiff. To make a stronger tube, make the tube the correct length by cutting some off both ends.) You need a total of 35 newspaper tubes measuring 71 cm and 30 tubes measuring 66 cm. So get busy rolling, measuring, and cutting. Keep the two lengths separated.

Use the marker pen to put a mark on the longer newspaper tubes. Now you'll be able to tell the two lengths apart easily. From now on, we will call the marked tubes As, the unmarked tubes Bs.
Constructing the dome:
Arrange 10 As in a circle.

Overlap the ends of two tubes by 2 cm and staple together. Repeat this to form the base of the dome.

Lay alternating pairs of As and Bs radiating out from the central circle.

Pick up two of the As and form a triangle with them and one of the As from the circle. Staple the joints firmly.

Do the same thing with the rest of the tube pairs. You should end up with a circle of triangles poking into the air. Tall triangles should alternate with short triangles.

Connect the triangles by stapling a row of Bs across the top.

Every point where four Bs come together, staple on another B pointing straight up.

Brace the Bs by using two As, one attached to each adjacent joint.

Connect the tubes by stapling a row of As across the top.

Finish the dome by adding the last five Bs. These tubes come from the five joints and meet in the middle.
Reprinted with permission of YES Mag

Product Dissection

This exercise, done in teams of two or three students is designed to give students an opportunity to take a machine or device apart. It allows students to see, first-hand the connections between science and engineering and helps them to understand the impact that engineers have on the lives of people.

Materials (per team):

• machine or device for disassembly (see below)

• screwdriver

• magnet to collect screws

• large piece of newsprint or flip chart paper

The device you select should:

• allow you to take it apart with simple tools

• be of a size that 3 to 5 students can work on it (not so small that one needs a magnifying glass to see, or so large that it is difficult to move and hold)

• have at least four, but not more than 30 mechanical components (springs, bearings, gears) inside

• have an electrical aspect to it (optional)

• cost less than $10 and allow students to see that even an inexpensive device contains a large amount of engineering

• be in working order

• need no detailed disassembly instructions

Possible devices under $10 include:

wind-up toys (cars, animals), VCR tape (to be compared with a cassette tape), shaver (a variety of
disposable shavers), ball point pen, electrical outlet, disposable camera, mechanical pencil, electrical switch, flashlight.

Other possibilities include:

clock, power or manual drill, food scale, fishing reel, electric razor, bathroom scale, pencil sharpener, toaster, telephone, lawn sprinkler.

Before Your Session:

Line up some help. Although you could effectively run the exercise yourself, the experience will be more personal if you have a couple of assistants. For a class of 30 students, two assistants plus the instructor works well.

You and your assistants should become expert in taking apart and reassembling the device.

If some aspect is particularly tricky, consider creating a handout on that part of the procedure.

Discuss the exercise with the teacher to determine class size, how to divide the class into groups, and how the exercise might fit into the curriculum.

Instructions:

Introduce yourself and your assistants, mentioning any products with which you have been involved in your work (take no more than 5 minutes).

Divide the class into teams of two to three students each.

Distribute the products to be dissected; ideally all teams should work on the same type of device, but you could have half the teams dissect one brand, and the other half, a second brand or type.

Have the students take about five minutes to "play" with their device, writing down answers to the following questions:

What does the device do?
How many parts are inside?
What scientific principles were used in making this machine?
How many engineers do you think were involved in making it?
What types of engineers were involved?

Have the teams spend no more than 25 minutes taking the device apart and putting it back together. Warn the teams when their work period is half over that they should begin to put the machine back together. As the students are disassembling, you and your assistants should be walking around the room offering suggestions or asking questions about what they are seeing. How have their answers changed?

Have the students stop working and have one member of each team orally present the team's answers. Record the answers on the blackboard or paper. You could leave the devices in the classroom for further exploration or complete reassembly.

Courtesy of National Engineers Week (U.S.)

Filtering - Slow and Steady Wins the Race

Did you ever wonder where all the water goes after you take a bath, brush your teeth, wash clothes or flush the toilet? Do we recycle that water and use it again? We do! Most of the water we use very day in so many different ways eventually finds its way to a water treatment plant where it is filtered, cleaned and put into a river or stream. This water flows to the ocean where it evaporates and rains down to eventually be used again.

One common way to help purify water is to use a filter. Most large purification plants use some form of filtering. Certain filtering systems work better than others. Let's see what works best for you!

Materials (per team): one paper towel 10 cotton balls small gravel (aquarium-size 120 ml cup) sand (about 120 ml) 250 ml of water, three 360 ml plastic foam cups one sharpened pencil three clear reusable plastic cups soil (about 360 ml) bowl masking tape crayon

Warning: Do not drink the water even if it looks clear. It has not been purified and is not safe to drink.

Instructions:

Use the point of a pencil to make a small hole (about the diameter of the end of the point) in the centre of the bottom of the three foam cups. With the masking tape and crayon, label the cups A, B and C.

Put the cotton balls in Cup A. Press them down into the bottom of the cup. This is Filter A.

In Cup B, pour in about 120 ml of sand and then about 120 ml of gravel so that the gravel is on top of the sand. This is Filter B.

In Cup C, push a paper towel down into the cup so that it touches the bottom. Tape the extra paper towel to the outside of the cup. This is Filter C.

Put 120 ml of soil into a bowl. Add 250 ml of water and stir until the water is dirty. Hold Filter A over a clear glass or plastic cup. Slowly pour the dirty water into Filter A. Observe the water as it drips into the cup below. Is the filtered water dirtier or cleaner than you expected?

Make another bowl of dirty water as you did before. Hold Filter B over another clear cup while you pour the dirty water slowly into Filter B.

Observe the filtered water as it drips into the cup. Compare the water from Filter B with the water from Filter A. Which filter made the water clearer? Do you think one filter works better than the other?

Make another bowl of dirty water. Holding Filter C over another clear cup, slowly pour the dirty water into Filter C. How does the water dripping out of Filter C compare with the water from the other two filters?

Discussion:

Which filter worked best? Which filter took the longest time for the water to drip through? Do you think that the time it takes for water to run trough a filer has anything to do with how clean the water will come out? Why?

Additional Challenge:

By combining the materials you just used, try to make a filter that allows the water to run through quickly but that cleans the water very well.

Reprinted with permission, WonderScience, November 1990, American Chemical Society

Rocket Transportation

Construct a balloon rocket and use it to carry a paper clip payload.

Discussion

Engineers and scientists have met many challenges to reach outer space with various spacecraft. The mass of a rocket can make the difference between a successful flight and a rocket that just sits on a launch pad. As a basic principle of rocket flight, a rocket will leave the ground when the engine produces a thrust that is greater than the total mass of the vehicle.

Large rockets, able to carry a spacecraft into space, have serious weight problems. To reach space and proper orbital velocities, a great deal of propellant is needed: therefore, the tanks, engines and associated hardware become larger. Up to a point, bigger rockets fly farther than smaller rockets, but when they become too large their structures weigh them down too much.

One solution is to attach small rockets atop the big ones. When the large rockets exhaust their fuel supply, the rocket case drops behind and the remaining rocket fires. Much higher altitudes can be achieved this way. This technique of building a rocket is called staging.

Materials

• large long balloons (several per student group)

• fishing line

• straws

• small paper clips

• tape

• clothes pins

• scales

Instructions:
(This activity works best with student teams of three or four.)

1. Attach a fishing line to the ceiling or as high on the wall as possible. Try attaching a paper clip to a fishing line and hooking it on to the light or ceiling tile braces. Make one drop with the fishing line to the floor or table top per group. Note: The line may be marked off in metric units with a marker to aid students in determining the height traveled.
    

2. Blow up the balloon and hold it shut with a clothes pin. You will remove the clip before launch.
    

3. Use the paper cup as a payload bay to carry the weights. Attach the cup to the balloon using tape. Encourage students to think of creative locations to attach the cup to the balloon.
    

4. Attach the straw to the side of your rocket using the tape. Be sure the straw runs lengthwise along the balloon. This will be your guide and attachment to your fishing line.
    

5. Thread the fishing line through the straws. Launch is now possible simply by removing the clothes pin. Note: The fishing line should be taut for the rocket to travel successfully up the line, and the clipped balloon nozzle must be untwisted before release.
    

6. After trying their rocket, have students predict how much weight they can lift to the ceiling.
   Allow students to change their design in any way that might increase the rocket's lifting ability between each try (e.g., adding additional balloons, changing locations of the payload bay, etc.)

Discussion:

Have students compare what they have learned about balloons and rockets and compare results of their experiments. Why is the balloon forced along the string?

Additional challenges:

Can you eliminate the paper cup from the rocket and have it still carry paper clips?

If each balloon costs one million dollars and you need to lift 100 paper clips, how much money would you need to spend? How could you cut costs?

Without attaching the paper cup as a payload carrier, have the students measure the distance the balloon travels along the string in a horizontal, vertical and 45-degree angle using metric units. Discuss the differences.

Courtesy of National Engineers Week (U.S.)
Activity provided by NASA

Homemade Slime

Materials:

• 120 ml. bottle white glue such as Elmer's

• 500 ml distilled water

• Food colouring or liquid tempera paint (any colour)

• Borax powder (can be found where laundry detergent is sold)

• Large jar

• Measuring cup, measuring spoon

• Mixing bowl (ceramic, glass or metal), mixing spoon

Instructions:

Pour glue into jar; fill empty glue bottle with distilled water and add to jar. Stir. Add 7 to 10 drops food colouring or 15 to 30 ml liquid tempera paint. Stir well.

Pour 250 ml distilled water in mixing bowl. Add 5 ml to 15 ml borax powder (the more concentrated the borax, the more viscous the mixture). Stir well until borax dissolves.

Slowly pour glue mixture into borax mixture, stirring constantly.

Remove the resulting slime from bowl and knead until it feels dry. Some water will remain in bowl. Store slime in tightly closed plastic bag in refrigerator.

Discussion:

What are the physical properties of slime? Knead, stretch, bounce, pour the slime. Cut it with scissors. Pour it into a pan and hit it with your fist. What happens when you leave the slime on a flat surface?

Slime is an example of a non-Newtonian fluid which does not act according to Newton's laws of fluid
behaviour. Newtonian fluids change viscosity (thickness or resistance to flowing) as a result of temperature changes. Non-Newtonian fluids such as slime can have their viscosity changed by applying force.

A polymer is a long, chainlike molecule formed by linking together smaller molecules called monomers. The combination of molecular length and flexibility gives polymers many useful and unique properties, such as elasticity and high viscosity.

Polymers can occur naturally and are also manufactured to produce many useful products. Examples of naturally occurring polymers are starch and wool. Synthetic polymers include plastics (polyethylene), vinyl (polyvinyl chloride), acrylics (polymethylmethacrylate), nylons (polystyrene) and polyesters.

In this slime, the glue (polyvinyl acetate) is a polymer. The borax (sodium tetraborate) acts as a crosslinking agent for the polymer molecules, creating even larger molecules. The resulting mixture, the slime, becomes even more viscous.

Safety tips:

Keep slime away from clothing and other surfaces which can be damaged by it, such as furniture and carpets. Slime is not edible! Wash hands after use.

To dispose of the slime, put in garbage. Never pour down drain or toilet.

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