Grade 7 Chapter 4 Test Date

The chapter 4 Test will be on Tuesday May 28.

A study guide will follow shortly.

Grade 7 Notes for section 4.2

Forces That Can Act on Structures

• Structures constantly experience forces; they must be designed to withstand the forces they will face (Force: any push or pull)
• If the structure isn’t strong enough it may experience structural failure.
• If the structure is too strong, time and resources may have been wasted.

Internal and External Forces

• External force: acts on an object from outside the object; e.g., wind, gravity, earthquakes
• Gravity
• is a natural force of attraction
• acts on all structures all the time
• pulls structures towards Earth’s centre

• other external forces
• a person on a ladder
• pulling a drawer open
• sitting on a chair
• cars on a bridge

• Internal force: one part of a structure acting on another part of a structure; e.g.,
• tension in stretched cables on a bridge
• compression by the weight of a roof on the walls

Describing Forces

To describe forces, engineers use three main things:

• The force’s:
• Magnitude (strength)
• The size of force compared to the size and weight of object
• Direction
• Where the force is coming from
• The point and plane of its application
• Point of application: the exact location where the force meets the structure
• Plane of application: the side of the structure affected by the force

External Forces and Loads

Every structure supports a load

• Total load: the sum of all the static and dynamic loads
• Static load: the effect of gravity on a structure (the weight of the structure itself) also called dead load
• Dynamic load: the force that moves or changes while active on the structure
• Called “dynamic” because they change their magnitude, direction, and point and plane of application.
• Wind is considered a dynamic load because its magnitude can change

E.g., a bridge: The static load is the weight of the bridge itself (dead load).

The dynamic load is the weight of the moving cars across the bridge (also called live load).

DRAW PICTURE OF TRUCK ON BRIDGE WITH LABELS HERE

Internal Forces

• Can be classified as:
• Compression – a force that squeezes or presses something together
• Tension – a force that stretches apart to expand or lengthen
• Shear – a force that pushes in opposite directions
• Torsion – a force that twists
• Bending – A force that acts to bend a component putting one side of the part in tension and the opposite side in compression

The forces occur within the human body as well since the human body is a structure; e.g., when a skater twists, torsion occurs within her body.

Designing for Forces

Engineers have to consider all these forces when designing structures, e.g., they have to consider the load of the snow on a bridge in addition to the truck.

Engineers design structures to withstand a hundred year storm, a large storm that occurs once in a hundred years.

Grade 7 Forces Activities

Internal Forces

1. Watch this brief video outlining the 5 internal forces. Please note there is no sound!

http://www.youtube.com/watch?v=8IN544ZKzmQ


2. Check out this link to work with the 5 internal forces

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


External Forces

1. Click this link to read about and test out external forces or loads

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


Materials

Do some experiments to test out which building materials are the best. Based on cost, strength, and weight; which building material do you think is best? Hint: read about the pros and cons!

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


Shape

Experiment with different shapes to see which ones are strongest. What makes the one shape so strong?

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


Fun stuff when you are done! Check out wonderville!

http://www.wonderville.ca/asset/forces-of-wonder

When complete, read about Bridge Basics and complete the Bridge Challenge!

http://www.pbs.org/wgbh/buildingbig/bridge/index.html

Grade 6 Biodiversity Unit Review

Grade 6 Biodiversity Unit Review

• Characteristics of Vertebrates (know the 5 classes)
• Fish
• Amphibians
• Reptiles
• Birds
• Mammals

• Food webs
• Carnivore
• Herbivore
• Omnivore
• Producer

• Benefits of biodiversity
• Clothing
• Recreation
• Medicine
• Food
• Household

• Threats to biodiversity
• Endangered
• An endangered species is a species of organisms facing a very high risk of extinction.
• Extirpated
• Local extinction, or extirpation, is the condition of a species (or other taxon) which ceases to exist in the chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions.
  
• Threatened
• Threatened species are any species (including animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.
• Extinct
• no longer in existence; that has ended or died out
• Special concern
• a species is of special concern because of characteristics that make it particularly sensitive to human activities or natural events

• Bioinvasion
• What is it?
• Impact of bioinvasion on biodiversity

• Monoculture Farming
• What is it?
• Pros
• Cons

• Benefits of wetlands
• Ducks unlimited website

http://www.ducks.ca/learn-about-wetlands/why-i-care/

Grade 7 Heat Technologies Task

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Heat Technologies Task

Please submit this task neatly typed.

Part 1

Read section 12.1 and 12.2 and define the

following terms:

• Heat pollution
• Heat island
• Natural greenhouse effect
• Enhanced greenhouse effect
• Greenhouse gases
• Global warming

Part 2

Read section 12.3 and answer the following questions:

1. Define “climate change”
2. Identify and explain 3 negative effects of climate change.
3. Identify and explain one positive effect of climate change.
4. List 3 ways that normal people (like you!) can help reduce climate change.

Part 3

a)      Select one of the following ways people can reduce the financial and environmental costs of home energy use

                                                              i.      A home that uses geothermal heating

                                                            ii.      A home that uses solar energy to heat water

                                                          iii.      A home that includes a green roof

b)      Research the financial and environmental benefits of this technology

c)      Create a poster educating people about it. Please be sure that your poster:

a.      Is on an 8.5x11 piece of paper

b.      Is neatly drawn, coloured, and laid out effectively

c.       Demonstrates a strong effort

d.      Shares relevant and accurate information

e.      Persuades people to help the planet

Grade 6 Poster Due Date and Biodiversity Test Date

Poster Due Date: Tuesday May 14

Final Biodiversity Test Date; Friday May 10

A study guide will be posted.

Grade 6 Wetlands Conservation Poster OR Benefits of Biodiversity Poster

The town of Willowdale is considering building a shopping centre on top of the local wetland in Earl Bales Park. You are part of a conservation effort to stop the destruction of this wetland.

Your task is to create a small poster to educate the public about the importance of wetlands. Use the following link to Ducks Unlimited Canada to learn more about wetlands:

http://www.ducks.ca/learn-about-wetlands/what-wetland/

You may do more of your own research if you like.

You will be assessed on the following:

1. Knowledge of Wetlands: At least 5 important facts about wetlands are included on your poster

2. Effort: Evidence of a strong effort are visible; e.g., the poster is neat and well organized, care was taken to make straight lines with a ruler, etc.

3. Balance of Features:

• There are images as well as text
• colour is used effectively
• font sizes are varied; e.g., larger font for titles, smaller fonts for additional reading about wetlands on the poster

YOUR SECOND OPTION

You may choose to do option 2 which is a poster adverstising the benefits of biodiversity.

For this poster, you are to select an area in which people benefit from biodiversity; the five areas are:

Clothing
Medicine
Food
Recreation
Household

1. Do some research relating to products that people use in your chosen area. You can begin your research here:

http://www.biodiversity-products.com/

2. Select a product or a series of products and research how we can thank biodiversity for their existence.

3. Create a poster explain why it is important to maintain biodiveristy for the benefit of society.

You will be assessed on the following:

1. Knowledge of How Product is Related to Biodiversity: The poster clearly explains how the product relates to biodiversity and how society benefits from this product.

2. Effort: Evidence of a strong effort are visible; e.g., the poster is neat and well organized, care was taken to make straight lines with a ruler, etc.

3. Balance of Features:

• There are images as well as text
• colour is used effectively
• font sizes are varied; e.g., larger font for titles, smaller fonts for additional reading about wetlands on the poster