Building Structures - Gr.3 Science - HOME



Teacher: Grade/ Subject: Grade 3 ScienceUnit: Building with a variety of materials Topic: cantilever, truss, intro to final bridge projectsDate: Length of Lesson: GLO: 3-3 investigate a practical problem, and develop a possible solutionSpecific Learning Outcomes: SLE 5 – identify the intended purpose and use of structures to be built, and explain how knowing the intended purpose and use helps guide decisions regarding materials and design. Learning Objectives:Students will learn about cantilever and truss bridges. Students will consider their previous knowledge while planning a bridge project. Students will work cooperatively with a partner. MaterialsNotebook presentation 5 dictionaries Okay so we are almost done learning about all the different kinds of bridges. Today we are going to quickly look at the last 2, and then we are going to move along into the introduction of your final bridge building assignment. Can anyone think back to what kind of bridges we still haven’t covered? Cantilever and truss. Go through the slides, explain the science behind them, demonstrate cantilever. (Basically it is like 2 diving boards facing each other that are connected in the middle. The piers that are holding up the ‘diving boards’ hold all the weight.)A cantilever bridge consists of a beam jutting form each side of a body of water. the beam is supported by concrete blocks or abutments. the two beams meet in the middle. if the bridge needs to be longer, a third piece or span is added between them. the beams of the cantilever bridge balance on a column in the center of each arch. It works like 2 big diving boards facing each other. Quick Demo - 5 books. - two standing up, 2 laid across so it is like two big Ts standing by each other, place the last book on top to join the two Ts.Explain truss – We don’t need to demonstrate this kind of bridge because we have already looked at trusses and we know that it makes structures stronger. Well it turns out that most bridges incorporate trusses in their design somewhere along the line. You can make a beam stronger by pairing it with a truss somewhere. Look at the pictures of bridges – some of these have arch-like patterns. Some of these are just popsicle sticks or straws. Held together with tape, glue, or pipe cleaners. 44437302476500Demonstrate – show them the bridge games. That I found – tell them that one is an app (Bridge Constructor FREE) but here are pictures of how it works. ), The other one is an online game – go to the link and demonstrate one, have them give you suggestions as you play. Just a straight beam isn’t strong enough. It helps if you Can support it to the abutments. You Can build it up like a truss. Attach diagonals to make it stronger. Need to consider COST in this game. I'm out of wood! think about the “joining” spots. Those are weak spots. Need to be connected at those spots! Cargo Bridge Introducing the final assignment 3 billy goats gruff YOUTUBE – video. 3 min 4583430-126492000Your town is hiring us to build a strong bridge for the Billy Goat farm. Our goal is to try and build one that can hold all 3 types of goats! (100 g, 500g, 1000g) – put little plastercine heads and tails on the weights so that they look like goats. Explain the money – each group is color coded. You only have 20 bridge bucks and 3 tape taxes. Tomorrow we will have the materials sorted into price ranges. (I had students bring in items from home and I categorized them into their “worth”) Some heavy-duty things will cost you like 5 bucks, but you might be able to buy more cheap stuff instead that are only 1 buck a bundle… have to be thinking about the cost and doing the math as you go! We will draw for colors to see who gets the first pick at the store. Do your first round of shopping, and then the next group can come buy. One person should be the banker who keeps track of the money and DOESN’T LOSE IT! Today is a planning day. Explain the handouts. Then show them their partners. Let them get to work! Can view the materials that we have so far. Any big requests for something we should try to get?Handouts – title page, review page, assignment, day 1 = plan your materials, your style of bridge, and draw a picture of what you think will work well. DifferentiationStudents have been paired according to who we think they will work well with.AssessmentThe students should have that first handout filled out. Are they working well together and being productive? – scale of 1-3, 1 = fighting, doing separate work, etc. 3 = engaged, working together, compromising. FINAL BRIDGE PROJECT: “BILLY GOAT FARM” 139065058483500BRIDGESNAME: ___________Team colour: __________________BRIDGE REVIEWBRIDGE TYPE & PICTUREDESCRIPTIONBeam BridgeA beam bridge is the simplest and most inexpensive kind of bridge. They were also some of the earliest and simplest ones to be used. Beam bridges consist of a horizontal beam supported at each end by piers. The weight of the beam pushes straight down on the piers. The farther apart its piers, the weaker the beam becomes. Arch BridgeThe arch bridges are used to span a deep gap. They are one of the cheaper bridges to build. The weight transfers down the sides of the arch and the abutments (the sides) keep the shape of the arch. Arches that are pieced together have a keystone at the top that hold the shape of the arch.Suspension BridgeUsed to span the longest distances. One of the more expensive bridges to build. The weight is held up by the big cables which are attached to the abutments at the shore. The cables are thread through the top of the piers instead of being directly attached to the piers.Cable-Stay BridgeOne of the modern types of bridges. All of the weight is directly held up by the piers and the cables in the middle. Covered BridgeCovered bridges were used back in the days of horses and buggies. They usually have a strong beam, walls that have trusses in them, and a pointed roof. They were useful so that the bridges would be more safe in bad weather, and so that bridges wouldn’t need to be fixed as often. These bridges are usually not very long, but we have the longest on in New Brunswick Canada. Cantilever BridgeThis bridge is like two long diving boards that are facing each other and then connected in the middle. The piers near the ends and the abutments at the shore hold the weight. The middle part is not as strong. These bridges are good because they don’t need the piers in the middle, so boats can still go through the middle. Truss BridgeTruss bridges come in all shapes and sizes. They usually have one strong beam and then they are help up with a series of triangles which are very strong. The triangles help to distribute the weight of vehicles. Many other types of bridges also have triangular trusses in their designs. My Name: _________________________________________________My Partner’s name(s): __________________________________________Our Team color is: ______________________________________________Goals:Coaldale ‘Billy Goat Farm’ needs you to build a bridge so that their goats stop getting gobbled up by the mean troll. You must:Build a bridge that can span a 40cm gap. Keep track of your money and choose materials to build your bridge. (Limited to 20 Bridge Bucks and 3 Tape Tax cards.)Construct a bridge using those materials. Find ways to fasten the materials. Test to see if your bridge can hold up all 3 sizes of goats (100 g, 500g, 1000g.)Fill out the construction paperwork as you go! Learn to cooperate and work well with your coworkers while building the bridge. 1st day of planning:Type of bridge we might want to build: ________________________________Type of materials we might want to use: ____________________________________________________________________________________________.How we plan to hold (or fasten) our bridge together: _____________________-6477003663960 ____________________________________________________________. Drawing of what you think your bridge will look like: TESTING DAY QuestionYesNoOur bridge spanned a 40 cm gap.Our bridge held the lightest goat.Our bridge held the medium goat.Our bridge held the heaviest goat.Our bridge was built with extra money or tape left over.I am happy with our bridge.My favorite part about our bridge was: _________________________________________________________________________________________________________________________________________________________________________.What would you do differently if you were to do this assignment again? __________________________________________________________________ ___________________________________________________________________________________________________________________________________. ................
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