Can something soft like a marshmallow be used to build something strong and stable?Garry Studer/Getty Images/iStockphoto
Let’s Talk Science and the Royal Society of Canada have partnered to provide Globe and Mail readers with relevant coverage about issues that affect us all – from education to the impact of leading-edge scientific discoveries. Let’s Talk Science offers a number of fun activities to get youth engaged in STEM. These hands-on activities encourage active learning and discovery using materials commonly found at home.
There are numerous ways to build strong structures with objects that may appear weak. The idea behind this activity is to recognize that certain shapes are very strong.
Are you willing to give up a sweet treat for the sake of science? Can you engineer a strong and stable structure out of something soft and fluffy?
What You Need
● Container of toothpicks
● Bag of marshmallows
● Various objects, from very light to heavy (books, blocks, containers, etc.)
What to Do Safety first! Throw all used marshmallows away after you are finished building and testing your structure. Do not eat them! Set aside some other ones for eating.
● Using only 20 toothpicks and 10 marshmallows, build a free-standing (standing alone without being attached to or supported by something else) structure that is as tall and as big as possible, that can also support an object.
● Try to have your structure support one object. If it can support this object, try adding another object. How many objects can your structure support?
● Now add another 20 toothpicks and 10 marshmallows to your structure, and see how many objects it can support.
● Keep adding toothpicks and marshmallows, and seeing how many objects it can support. See how big you can make it!
What’s happening?
Certain shapes are very strong! Take the C.N. Tower in Toronto, Ontario, Canada, it is one of the tallest free-standing towers in the world. Its base is actually triangular: there are ribs that go down the length of the tower, but, if you were to look down, and draw a line around the base, it would be a triangle.
Another very strong shape is the cylinder. A single cylinder can be very strong, just not stable. If the base of the C.N. Tower were cylindrical, it would fall over with the first wind gust. However, if you make the base of a structure out of four cylinders, positioned in a square about the base of the building, then it would be extremely strong and stable.
Why does it matter?
All structures, even marshmallow towers, are built to support a certain load. There are two general categories of loads: static loads (that do not change) and dynamic loads (that change).
Within static loads, there are two main subcategories: dead loads and live loads. The dead load of a structure is the weight of the structure itself or anything else physically attached to it. Live loads are subject to change, but the loads are expected to occur during the regular use of a structure, such as cars or trucks passing over a bridge.
Dynamic loads are sudden impacts and can be unexpected. They may exert forces that are out of the ordinary like hurricanes, earthquakes and large waves. Engineers need to consider these dynamic forces and try to design and construct buildings that have the ability to withstand these unexpected loads as well as the expected static loads.
Investigate further
● Try building a new structure using the marshmallows. How many types of structures can you make? Which of them are the strongest? Which ones are not so strong? What shapes work the best?
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