Structures Physics Grade 6/7

What is the coolest structure you can think of?

Brainstorm: What are some things we think about when we design and build something?

 Function  Efficiency  How it looks (aesthetics)  Effect on the environment  Cost  Safety  Legal concerns  How long it will last  How long it will take to build  Individual likes and dislikes

Load: A force acting on a structure

Building Challenge  With a partner create a bridge that spans 15 cm and can support a toy car (live load).  Materials:  Straws  Aluminum Foil  Tape

Technological Problem Solving  Scientists and engineers don’t just stop when they fail.  They figure out the problem and think of ways to solve it. They then try out their ideas, and if they fail again they try something else.  This is technological problem solving!  How could you improve your bridge?

Classifying Structures  Solid  Frame  Shell

Solid Structures  A solid structure is an object that uses solid construction to support loads.

Frame Structures  A frame structure is a network of parts that supports a load.

Shell Structures  A shell structure is a hollow structure with a curved shape providing high strength and rigidity.

Build an example of each of the 3 types of structures…solid, shell, frame. Be creative!!

Forces  The push or pull on an object.

Forces have magnitude and direction..  Magnitude= size or strength of a force  Direction= left, right, up, or down  **Forces are represented by arrows in diagrams.  A thicker arrow means the force is greater.

Air  Activity 1: Air Takes Up Space  1. Fill a ziploc bag with air by opening it and pulling it through the air.  2. Quickly close and seal the bag.  3. Look at the bag of air. Poke the bag; push down on the bag (gently); and open the bag and smell the air. Record your observations in your notebook.

Air  Activity 2: Air Has Pressure  1. Place the metre stick on your desk so that it extends 20 cm over the edge of the desk.  2. Place a sheet of newspaper on top of the metre stick on the desk.  3. Smooth out the newspaper, removing as much air as possible between the table and the newspaper.  4. Quickly push down on the end of the metre stick. What happens?

Air  Activity 3: Air Has Mass  1. Blow up two balloons, so that they are about the same size.  2. Tie a piece of string to each of the balloons.  3. Stick a piece of masking tape on the side of one of the balloons.  4. Tie one balloon to each end of a metre stick (10 cm from each end).  5. Tie a piece of string to the centre of the metre stick. Move the string until the metre stick is balanced. Carefully tape the string to the metre stick so it won’t move. Secure the metre stick to a desk so it stays balanced.  6. Pop the balloon with the tape on it, using a pin. Observe what happens?

All about air!  Air is a combination of gases, mainly oxygen (20%), and nitrogen (78%).  Air is colourless and odourless.  Air is all around us.  Air takes up space.  Air has mass.  Air has pressure.

External Forces  External Forces: a force acting on something from the outside.  Gravity  Applied Force  Natural Disasters (ie. earthquake)

Internal Forces  Internal Forces: a force acting within an object, between two different parts. Force TensionPulling Apart TorsionTwisting ShearPush and/or pull in opposite directions (rip/tear) CompressionPress/ Squeeze

Build a Bridge  Create a bridge that spans at least 15 cm, using the materials provided.  Materials  50 popsicle sticks  20 toothpicks  Glue gun and 2 sticks of glue  Once your bridge is built, you will draw a force from the bucket to test the strength of your bridge. Roll dice to see what force will act on your bridge. So yes, your bridge needs to be able to withstand all forces!

Forces Affecting Flight

Building an Airplane  Build an airplane to fly the longest distance by folding paper.

Movie on Flight

Quiz  Based on grade level.

Stability  Structures need to be stable and balanced when forces act on them.  Structures will be more stable if…  1. They have a low centre of gravity.  2. They have wide base support.

Centre of Gravity  The point at which an object’s mass is equally balanced in all directions.  Try This:  1. Balance a metre stick using 1 finger.  2. Now try using 1 hand.  3. Now try with both hands.  What do you notice during this activity?

Symmetry  An exact reflection on opposite sides of a line, dividing an object in half.  Symmetry is important for the aesthetics of a structure (ie. how visually appealing it is).  Which building would you prefer to live in?

Structural Failure  Bridge Collapse vs. Plane Crash  Tacoma Bridge Collapse (1940): d=10 d=10  Tawian Plan Crash (2015):

Structure Safety  How could this “failure” be improved? What new technology exists to make structures safer?

Quiz/ Exit Ticket  Grade-level

Impacts on the Environment  What impacts do the building of structures have on the environment?  407  Pickering Airport  New Shopping Mall  New Subdivisions  New Schools

Inquiry- Based/ Review  Question box, etc.

Unit Assignment

Unit Test