Toothpick Towers

Build Toothpick Towers

Build the tallest tower that can withstand an earthquake and learn how engineers use the strength of different shapes to design structures that can withstand the demanding elements.

What you need: 

• Toothpicks (be careful, the ends of toothpicks can be quite sharp). 

• Something for your toothpicks to stick into and help hold your tower together – mini marshmallows, gum drops, plasticine or modelling clay, or Styrofoam balls all work.  

• Flat table or surface to build your tower on. 

Supplies for Toothpick Tower

What you do: 

1. Make shapes by inserting your toothpicks into your Styrofoam balls, marshmallows, gum drops or clay. Whatever you choose to stick your toothpicks into will be the corners of your shapes. Make a two-dimensional triangle using three toothpicks and three corners, and a two-dimensional square using four toothpicks, and four corners. 

Triangle

Square

2. Test the strength of your shapes. Press down on your square. What happens? Does the shape still hold together or does is bend and twist? Do the same for your triangle. What happens? Which shape do you think is stronger? What shape do you think would be best to use to build a strong tower? 

Test the Triangle

Test the Square

3.A cube is a three-dimensional shape that has six sides, like a game die. Build your square into a cube by adding a vertical toothpick to each corner, and then complete the remaining squares on each side of your cube.  

4.Test the strength of your cube by pressing down on it like we did before. What happens? Is the shape stronger now? Does it hold its shape, or does it bend and twist? 

Cube

5. A tetrahedron is a three-dimensional triangle that has four sides. Build your triangle into a tetrahedron by adding a vertical toothpick into each corner, and then gather the three points of the toothpicks together in the centre and add the final corner. 

6.Test the strength of your tetrahedron by pressing down on it like we did before. What happens? Is the shape stronger now? 

Tetrahedron

7. What other shapes could you build and test to see which is the strongest? See the shapes below for some other shapes to try. 

Now that we have an idea what shapes are strongest, we must design our tower. You can either draw your design, or just start building your idea to see what works and what does not. 

For this challenge, design and build a tower that can: 

1. Be a freestanding structure – meaning it can stand on its own without you holding it up or sticking it to the flat surface you are working on.  

2. Try and only use 25 toothpicks. 

3. Build it as tall as you can. 

If something you design does not work, try again with a new idea. Don’t give up! Science is all about trying out new ideas and asking questions. 

Tower Made With Cubes

Tower Made With Tetrahedrons

Explanation 

An engineer is a person who designs and builds complex products, machines, systems, or structures. Engineers want to know how and why things work. They have scientific training that they use to make practical things. (National Geographic). 

Structural engineers must consider many factors when designing a structure such as what is the purpose of the structure, where is it going to be, what kind of ground will it be built on, what kind of weather will it be faced with, what materials will be best to use and many other considerations. 

Throughout this challenge, you participated in a similar engineering design process.  

Engineering Design Process

What is a freestanding structure? 

Freestanding means that it doesn’t need another structure to support it. Most houses are freestanding structures. The tallest freestanding structure in Canada is the CN Tower in Toronto. It was completed in 1976 and is 553.3 metres high. The tallest freestanding structure in the world is the Burj Khalifa completed in 2009.  It is 829.9meters high located in Dubai, United Arab Emirates.  

CN Tower, Toronto, Canada

Burj Khalifa, Dubai, UAE

Important terms:  

• Buckling: When a material bends under compression. 

• Compression: When a force pushes materials together. 

• Elasticity: The property of a material to bend or deflect, and then return to its original shape. 

• Force: Any influence that tends to accelerate an object; a push or a pull. 

• Load: The weight which a building or structure must carry. 

• Dead Load: The weight of the building itself plus all permanent fixtures; it does not change. 

• Live Load: Weight of the objects which move in, out, or shift in the building (people, furniture, etc.); it is constantly changing. 

• Plasticity: The property of a material in which it does not return to its original form after a bend or deflection. 

• Shear: When a force slides material against one another. 

• Tension: When a force pulls materials apart. 

 Taking it further 

• Once you have a tower design that is free standing you can measure how tall it is.  

• Gently shake the flat surface you are working on to simulate an earthquake or a windstorm. Does your tower still stand? What can make it stronger?  

• What can you place on top of your tower to test its strength? A book? A soup can?  

• How sturdy and tall can you make your tower using 50 toothpicks, or 100?  

• Keep designing and trying new towers.  

• What other structures can you build? 

• What would you need to consider if you were to build a bridge? 

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Pasta Bridges

Build Pasta Bridges

Building a bridge that can withstand the elements requires some creative thinking, careful planning, and testing. Design and build the strongest bridge you can with uncooked pasta.  

What you need:

• Two pie plates turned upside down. These will act as the gap your bridge will try to cross. Any two items of the same height will also work 

• Uncooked spaghetti - as much as you need (depends upon how long you want your bridge to be!)

• Plasticine or modelling clay 

• Hot glue gun (Have an adult help you with this!) 

• Elastic bands 

• Ruler 

• Tape 

• Weights or toy cars to test the strength of your bridge 

• Several pieces of paper  

• Something to write with 

What you do:

• A bridge is a structure that crosses over an open area, such as a river or mountain valley. Before we build our pasta bridge, let’s test some basic ideas. 

• Place your items that are the same height on a flat surface and measure the distance between them. A suggested distance is about 30 cm. If you are using pie plates, be sure to place them on the surface so the bottom is facing up.  

• Cut a strip of paper about 7 cm across, and a bit longer than the distance you measured between your two items. 

• Place the strip of paper on top of the two items. Place your toy car on the paper to test to see if your simple paper bridge can hold the weight of the toy. What happens? Most likely, your strip of paper was not strong enough to hold the weight of the toy car and your toy car fell. What can we do to make this bridge stronger? 

• Engineers create strong bridges by combining different types of structures together such as beams, arches, trusses and suspensions. In the explanation section below, there are some examples of each type of these structures. We are going to test three of these structure types in paper first before we get to work building our pasta bridge. 

• Using some paper and a pen or pencil make a simple chart like the one below: 

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Bridge Structure	What Happened?
---------------------	---------------------
Beam
Arch
Truss
Combination

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• For beams, try making a paper tube the same height as your pie plates and place it the middle of the distance between the pie plates. Now, place that strip of paper we did the first test with on top of the beams. Test your beam bridge with your toy car. What happens? Record what happens in the chart you made. What happens if you use two beams, or three? Test and record your results in the chart. 

• To test an arch, take another strip of paper about the same size as the first one and try to curve it into a half circle.  You could also use a paper cup on its side. Place your paper arch between the pie plates, and your first strip of paper on top of your arch. What happens? Record what happens in the chart you made. What if you used multiple smaller arches? Test and record your results in the chart.

• To test trusses, take another piece of paper and fold down the top about 3 cm down. Turn the paper over and fold down again another 3cm. Repeat folding back and forth until you have folded your way to the end of the paper. You should have something that looks like this: 

• Put your folded piece of paper in between the pie plates, and your test strip of paper on top of the folded paper. What happens? Record your results in your chart. 

• Now try some combinations of these structures. Test an arch with trusses, or an arch of beams. Keep testing your car on each combination you come up with and record your results in the chart. 

• Now that we know a little about what makes a bridge strong, let’s design our pasta bridge. Draw out your design on a piece of paper. Don’t forget to include what we have learned so far about the different types of structures engineers use in their bridge designs.  

• Build your pasta bridge design. You can use a hot glue gun if there is an adult around to help you, or you can use elastic bands, tape, or modelling clay to construct your pasta bridge.  

• Once complete, don’t forget to test the strength of your bridge and record your results. How can you change your design to make your bridge even stronger? 

Explanation: 

• Bridges have been built for thousands of years using a range of different materials such as rocks, mud, lumber, metal, concrete, and even glass. The strength of a bridge is determined by its structure, not the materials it is made of. 

• Engineers create strong bridges by combining different types of structures together such as beams, arches, trusses and suspensions. 

• Here are some examples of different structures engineers use when designing their bridges: 

BEAMS 

Beam bridges use pillars dug deep into the ground or foundation to support the weight of the bridge on top of the pillars. 

ARCHES 

Arch bridges use an arch underneath the pathway to support the weight of the bridge, and also allows people and vehicles to pass under the bridge. 

TRUSSES 

Truss bridges use multiple triangles and walls to give a bridge strength.

SUSPENSIONS 

Suspension bridges use cables between the deck of the bridge and towers along the bridge to help hold the weight of the bridge.

An engineer is a person who designs and builds complex products, machines, systems, or structures. Engineers want to know how and why things work. They have scientific training that they use to make practical things. (National Geographic). 

Structural engineers must consider many factors when designing a structure such as what is the purpose of the structure, where is it going to be, what kind of ground will it be built on, what kind of weather will it be faced with, what materials will be best to use and many other considerations. 

Throughout this challenge, you participated in a similar engineering design process. 

Important terms:  

• Buckling: When a material bends under compression. 

• Compression: When a force pushes materials together. 

• Elasticity: The property of a material to bend or deflect, and then return to its original shape. 

• Force: Any influence that tends to accelerate an object; a push or a pull. 

• Load: The weight which a building or structure must carry. 

• Dead Load: The weight of the building itself plus all permanent fixtures; does not change. 

• Live Load: Weight of the objects which move in, out, or shift in the building (people, furniture, etc.); constantly changing. 

• Plasticity: The property of a material in which it does not return to its original form after a bend or deflection. 

• Shear: When a force slides material against one another. 

• Tension: When a force pulls materials apart. 

 Taking it further: 

• Try building a bridge out of paper and tape and see if your bridge can hold the weight of 100 pennies. 

• Try testing how suspension structures work. 

• Take a walk around your neighbourhood and see if you find any bridges. Draw the different structures that you see that make the bridge strong. 

• How much weight can your bridge hold? 

• What is the longest bridge you could build? 

• Can your bridge survive a windstorm or an earthquake? How could you test that? 

• Try building a cantilever bridge as shown below. 

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Mission Parachute Drop

Mission Parachute Drop

Here is a summertime twist on the classic egg drop engineering challenge. Instead of protecting an egg with a parachute you design and create one that will prevent a water balloon from bursting when dropped to the ground using only the supplies listed. 

What you need:

• 1 piece of paper (tissue paper or newspaper) 

• String (no more than 100 cm)  

• 6 straws or wooden popsicle sticks 

• 25 toothpicks 

• Plastic garbage bag  

• Aluminum foil (1 piece) 

• Masking tape 

• Small balloon 

• Water 

• Scissors

What you do:

• Research images of parachutes. How to they look when falling? What makes them expand? What forces are utilized when the parachute drops? How can a person or object be protected as they land?  

• Your challenge is to make a parachute with the water balloon as cargo. You will need to make your parachute land slowly and fall to the ground safely. 

• Gather materials: use only the materials listed to make it more challenging. From the images you saw and the supplies available sketch out the design of the parachute.  

• Cut a large piece from the plastic garbage bag. Make your own design, either round, square or octagon. This is the canopy.

• Cut small holes around the edges of the canopy so the string can be attached. Secure the holes with a bit of tape. 

• Attached the string to each hole. Add more tape to make sure that the string will not pull through the plastic.  

• Create a basket or holder for the water balloon from the straws, popsicle sticks, and toothpicks. Cover any sharp edges with aluminum foil, plastic and tape. Make sure the balloon can fit safely and securely.  

• Fill the balloon with water keeping it small enough to fit safely into the basket you created.  

• Test your parachute: Find an outdoor location in which you can stand on a surface that elevates you about one metre from the ground. Places such as the top of a deck, the ladder of a slide, or from a picnic table. Be sure to ask an adult for help with climbing.  Make sure that the water balloon is secure and safe in the basket. Count down and release the balloon and parachute.  

• Observe the results. Was your parachute built to safely land the water balloon on the ground? What things would you change? If the parachute was dropped from an airplane, would it survive the drop? Make changes and modification to the parachute and try it again!   

How it works: 

• Everything including air is made of matter. You may not always feel it, but air is always pushing on you. Think about a time you rode your bike fast or had a window open when the car was moving, did you feel the air on you? This is called air resistance or drag. Drag is the force that is felt when a solid object moves through air. When designing a parachute, you want there to be a lot of drag on the object that is falling so that it slows down, reducing its speed and making it land soft.  

• The design of a parachute is important. Most parachutes are round, and dome shaped but some are made rectangular. The rectangular parachutes have many cells for air to get caught in and slow the object as it falls.  

Taking it further:

Test the gravitational force: try dropping two objects that weigh different amounts, such as a rock and a feather, to the ground and observe how they fall. Galileo conducted this experiment a long time ago, by dropping a feather and a rock from a tower. He wanted to know if the weight of an object affects how fast it will fall.  When you did this experiment did you notice that the rock landed first.  It was not because it was heavier but because of its shape. Just like a parachute a feather shape causes it to float down using as much drag as possible in landing.  

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Dr. Kara Loos Shares Her Knowledge About COVID-19

This interview is part of a series explaining the COVID-19 pandemic. Please consider starting at Part 1: What is a virus or check out the whole series by clicking the button below.

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About Dr. Kara Loos

Dr. Kara Loos is a genomics research associate from the Institute for Microbial Systems and Society (MISS) at the University of Regina. She has been a part of the team conducting research and testing on SARS-CoV-2.

About the Interview

In this interview, Dr. Kara Loos answered some of the most frequently asked questions about viruses in general, corona viruses, the COVID-19 pandemic, and the future of research in microbiology.

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Science Says: Wear A Mask

This is Part 4 of a series explaining the COVID-19 pandemic. Please consider starting at Part 1: What is a virus or check out the whole series by clicking the button below.

A Brief History of Mask Usage

Today it’s common knowledge that microorganisms such as bacteria and viruses may cause disease in plants and animals (including humans). But a few centuries ago, the causes of infectious diseases and their methods of transmission were not known. Here is a brief summary of how our understanding of disease transmission has evolved and how science proved that something as simple as wearing a mask helps to prevent the spread of disease.

17th Century

Many of the top scientists of the era believed that disease was carried by bad smells or “miasmas”. As a result, their strategy to avoid spreading disease revolved around the avoidance of bad smells.

The first masks appeared during the later waves of the bubonic plague. A French doctor, Charles de Lorme, designed a special suit for physicians treating plague patients. It consisted of a large leather tunic, gloves, boots, a hat, and a mask in the shape of a bird’s beak that contained aromatic herbs.

Plague Doctor, Rome, Circa 1656 via Wikipedia

Even if the doctors of that time did not know the actual cause of disease transmission, this attire played a part in protecting them from the plague. The leather protected them from disease-carrying fleas, the gloves prevented direct contact with patients, and the herbs in the nose had antiseptic properties, thus neutralizing bacteria passing directly from one individual to another.

19th Century

In the mid-19th century, French chemist and microbiologist Louis Pasteur showed that fermentation and putrefaction are caused by organisms in the air. Later in the 19th century, scientists including Pasteur, Lister, and Koch proposed theories that living organisms called germs were responsible for causing and spreading disease.

“Germ theory, in medicine, the theory that certain diseases are caused by the invasion of the body by microorganisms, organisms too small to be seen except through a microscope.”

-Britannica.com

This theory revolutionized the human understanding of infectious diseases and toppled the miasma theory. In 1870 John Tyndall, an Irish physicist, presented a paper to the Royal Institution in London in which he demonstrated that dust in the air could contain germs and disease and that a cotton-wool respirator could filter them out. Applying his research, he developed a much-improved gas mask for firefighters.

“If a physician wishes to hold back from the lungs of his patient, or from his own, the germs by which contagious disease is said to be propagated, he will employ a cotton wool respirator … Such respirators must, I think, come into general use as defense against contagion.”

-John Tyndall, On Haze And Dust

20th Century

During the early 20th century, various types of cloth masks (made of cotton, gauze, and other fabrics) were used in US hospitals to protect healthcare workers from diphtheria and scarlet fever. Wu Lien-teh, a public-health specialist from Malaya, was investigating a pneumonic plague that had broken out in northern China. He developed a mask from layers of gauze enveloped in cotton, with ties so that it could be hung on the ears. This was the prototype from which the masks currently used in medicine today evolved.

During the 1918 Spanish influenza pandemic, masks made of various layers of cotton were widely used by healthcare workers and the general public. Gauze masks were used during the second Manchurian plague epidemic in 1920–1921 and a pneumonic plague epidemic in Los Angeles in 1924; resulting in a decrease of infection rates among healthcare workers.

During the 1930s and 1940s, gauze and cloth masks were used by healthcare workers to protect themselves from tuberculosis. In the middle of the 20th century, after disposable medical masks had been developed, the use of cloth masks decreased; however, cloth mask use is still widespread in many countries in Asia.

Modern Masks And How they Work

How Can Cloth Masks Prevent the Spread of Disease?

When we breathe, talk, cough, sneeze, or sing, we emit droplets across a range of sizes, and these particles may contain viruses. Putting on a cloth mask can trap these droplets and prevent the virus from spreading to other people.

Cloth is a woven material, with threads intersecting each other in a pattern. It’s true that there are gaps between the threads and that these gaps are larger than the width of a single virus. Sometimes people are lead to believe that the virus is able to simply sail through a mask, but this isn’t true.

.Although the size of a single virus is smaller than the size of the gaps between the individual fabric threads of the mask, the size of the droplets that contain viruses could be bigger than these gaps. In addition, even though there are gaps between the threads in cloth, the individual threads are wider than the gaps. In addition, each thread has microfilaments or imperfections that project into the gap, further providing an obstruction. Finally, a good mask has multiple layers (Health Canada recommends masks with 3 layers) for extra protection.

It’s also worth noting that the droplets containing the virus don’t move in a straight line - they move and swirl in the air which makes them aligning with and passing through a tiny hole very unlikely. And, as droplets are not living things they can’t change direction to go around the fibers or move to avoid obstacles in their path.

Don’t be concerned about an individual gap in the weave of a fabric - instead, think of the entire mask with multiple layers and how everything works together to act as a filter.

Source: Center For Disease Control

Source: The Conversation

What Is An ‘N95’ Mask?

An N95 mask is technically a respirator. In order to use the term N95, the mask (respirator) must be certified by NIOSH - the National Institute for Occupational Safety and Health. During the COVID-19 pandemic we have begun to think of them in association with the medical field, but N95 respirators are used as protection in a number of non-medical fields ranging from autobody repair to construction, welding, and more.

The name N95 is actually a description of the capabilities of the respirator. The ‘N’ means that the respirator is not resistant to oil, and the 95 means that they filter 95% of 0.3 micron and larger materials. There are even multiple types of N95 respirators - including those intended specifically for surgical use and those with or without breathing vent holes.

N95 Respirators utilize capture or filtration to remove airborne particles as described below:

• The particles that come in direct contact with the fiber cannot pass through the filter

• Larger particles have too much inertia and thus can’t follow the airstream as it is diverted around the filter.

• Small particles are easily moved and deviated by air molecules, making it likely that they come into contact with a filter fiber.

• For the particles that are neither small enough nor large enough to be captured by any of the methods described above, N95 respirators utilize a type of electrical charge. The charge on the fiber filter attracts the oppositely charged particle, stopping all oppositely charged particles from passing through the filter regardless of their size.

In all cases, once a particle comes in contact with a filter fiber, it is removed from the airstream and strongly held by molecular attractive forces. It is very difficult for such particles to be removed once they are collected.

What’s The Point If Masks Are Not 100% Efficient Or If Other People Don’t Wear Masks?

When it comes to viral science, numbers count. It is true that if everyone in a community wears a mask, the probability of infections drops drastically. The studies clearly show that the more people there are wearing masks, the less the disease will spread.

That is because wearing a mask helps not only the wearer from coming in contact with the virus, but also helps prevent an infected person from spreading the virus. In other words, they offer two-way protection: when breathing in and when breathing out.

Avoiding Misinformation And Memes

There is a lot of incorrect and misleading information available on the internet, and sometimes that information is shared by friends or family members; sometimes even people that we trust.

Just because someone shares incorrect information, that doesn’t mean that they are a bad person - it just means that they’ve made a mistake. Unfortunately, it’s not always easy to tell when a piece of information is wrong. The most convincing, and dangerous, forms of misinformation are those that appeal to our “common sense” or that seem logical when first viewed.

For example, look at this meme often seen on Facebook:

Don’t Be Fooled By Misinformation!

At first look, it appears to make sense: why do I need to wear such a complicated mask when using spray paint, but cloth masks with images of Baby Yoda are enough to protect me from COVID-19?

The answer, also explained above, is simply that while the gaps in a cloth mask may be larger than the size of a single SARS-CoV-2 virus, the virus spreads in liquid droplets. A single layer of cloth might not be great against a single virus, but a multi-layer cloth mask, as recommended by Health Canada, has been proven to be effective against droplets containing the SARS-CoV-2 virus.

Other common pieces of misinformation about masks are that face masks can cause other health problems (not true) or that if you wear a mask you don’t need to practice social distancing (you still do).

Sometimes misinformation comes from a misunderstanding of a scientific article, from old information, or a single report or study that might have errors in it. It’s always a good idea to search for multiple reputable sources of information when trying to confirm a piece of information or advice that you hear.

Wearing a mask is a simple thing that you can do to help protect yourself and others from COVID-19. The more things you can do (masking up, social distancing, staying home when possible) the more protection you afford to yourself and those around you, including the people that you love.

How To Choose The Right Mask

Here are a few things to consider when selecting a mask:

• Wear a mask that fits snugly on your face

• Put on the mask such that it covers both mouth and nose at all times

• Choose a mask with two or more layers of breathable fabric

• Use only masks without exhalation valves or vents because they may not prevent you from spreading COVID-19

For more details and the latest updates on mask recommendations, please visit:

Health Canada: https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/prevention-risks/about-non-medical-masks-face-coverings.html

World Health Organization: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks

Center For Disease Control: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html

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