Please Bring in 2 Nickels!

We are doing an activity this week that requires 2 nickels (five cent coins) that you will be able to bring home afterwards.

Jib Building Worksheets

The package of planning and reflection worksheets are due the day following your jib testing date. Most groups have completed testing and already submitted their package for assessment.

If you have not submitted your package, please do do tomorrow.

Bangladesh Building Challenge

At this point you are working on

STEP 1 - Initiating and Planning and STEP 2 - Investigate 


For STEP 1 - Complete the Initiating and Planning section on the back of the Bangladesh Building Challenge worksheet. You will need to describe the situation and identify the problem that needs to be solved. A diagram is recommended.

For STEP 2 - You will have started working on this step in the computer lab this week. You are to brainstorm 4 different tower crane jib designs. Each design should be sketched in the space provide on the "Investigate" worksheet you received in class.

You should use 2 different colours to identify where the internal forces of tension and compression are in action on your sketch.

BOTH OF THESE SHEETS ARE TO BE COMPLETED FOR YOUR NEXT SCIENCE CLASS!

Don't Forget!

Review the reasons why the Tacoma Narrows Bridge collapsed!

I hope you all have already started to review the material! :)

Designing for Safety Worksheets Answers

Designing for Safety

In this section, you will learn about some of the way in which designers plan safety into structures and the factors they consider when designing and monitoring them.

No one can design a structure to be 100% failure proof. The materials may wear down over time. A person may use it incorrectly and break it. Unexpected forces might come into play

Engineers use the techniques of risk management to reduce the risk of failure as much as possible.

They deal with known risks in one of three ways:

Ignore the risk

Avoid the risk

Design for the risk

When a risk unlikely to occur, it can be ignored. E.g., an elephant sitting on a classroom chair.

Building a bridge with no supports in the water is a way to avoid the risk of boats colliding with the bridge supports.

When designers design for risk they often over-compensate for the various risks. They often make the structure stronger than really needs to be; e.g., stronger bridge supports in the water in case of a boat collision.

They also build in back-up and warning systems that may use sensors.

Designing for Loads

When designing a structure, the designers must calculate the load it will support. They design the chair to support more than itself plus the biggest occasional load. Some structures have warning notices about the maximum load they are designed to support, e.g., an elevator.

The Ontario Building code gives minimum standards for all aspects of building, including load bearing design and materials. This assures the public of a certain level of safety.

The Ontario Fire code is a law in Ontario that states that every home in Ontario must have working smoke alarms on every floor and outside all sleeping areas. Properly installed working alarms can warn people to get out of a burning building. This reduces the number of fire-related injuries and deaths.

Designing for Efficiency

Something described as “efficient” operates well without a waste of time, effort, or expense. E.g., if two students build bridges that support the same load, the bridge that uses the least amount of materials (usually by weight) is considered more efficient.

Sensors

A sensor is any device that can detect or measure real-world conditions. Different sensors can detect heat, lights, pressure, or sound, as well as changes in the amounts of these things.

Make a list of sensors found in your home:

Smoke alarm

Carbon-dioxide alarm

Thermostat

Motion sensing lights

Motion sensor alarm

Chapter 4 Test Study Guide

The following key terms and concepts should be reviewed prior to the test on:

Wednesday October 28th.

Section 4.1 Classification of Structures

1. Form and function
2. Ergonomic design
3. The 3 way to classify structures: form, function, construction
4. The 3 structural forms: frame, solid, shell (many structures are combination structures)

Section 4.2 Forces That Can Act on Structures

5. Internal forces: tension, compression, shear, torsion, (bending - combining tension and compression)
6. External forces: gravity, wind, cars, etc.
7. Describing forces: magnitude, direction, point and plane of application
8. Loads: total load, static load, dynamic load
9. Designing for forces: structures must support total load, a 100-year storm

Section 4.3 Designing for Safety

10. Risk Management:ignore the risk, avoid the risk, design for the risk
11. Designing for Loads: Engineers design for the more than the largest possible load
12. Designing for Safety: Ontario Building Code, Ontario Fire Code
13.Designing for Efficiency: What makes a structure efficient?
14. Sensors: Where are they used? How do they make people safe?

Practice Activities for Forces

Forces Lab

http://www.pbs.org/wgbh/buildingbig/lab/forces.html

Loads Lab

http://www.pbs.org/wgbh/buildingbig/lab/loads.html