Structures
We are learning how we can make structures strong and stable.
Structures are things that are built to support a load or hold something.
-Stuctures need to be STABLE so that they do not fall over when there is force on them. If something is stable, it means it balances and does not fall over.
-Shorter and wider structures are more stable than tall and narrow ones.
We can make structures more stable by adding weight to the base. (Think about the tube experiment!)
For example, the CN Tower is very high and narrow, but it is made stable by a huge concrete block that supports it underground.
-Structures need to be STRONG so that they do no break when their is force on them. If something is strong, it means it will not be broken by a force.
-Triangle shapes can be added in structures to make them stronger.
Using stronger materials also makes structures stronger. We can also make layers with our materials to make a structure stronger. (Think about the straw cube experiment!)
Human-built structures, like schools, homes, skyscrapers, statues... etc. are built for a purpose (reason).
For example, an apartment building is built so that people can have shelter.
Human-built structures can impact the environment in different ways:
Negative impacts-
-grass and farmland is destroyed
- the trucks that transport materials for building structures can pollute the air
- materials for building structures are sometimes taken out of the environment, for example from mines
Positive Impacts-
- some structures provide us with shelter and entertainment
- some structures bring money for the economy (ex. shopping malls)
- some structures provide us with electricity (ex. windmills give us windpower)
Animals built structures as well! They build structures for one of three reasons:
1. To create a protected home
2. To trap prey for food
3. To communicate to other animals of the same species
Some examples of animal structures include:
- beehives
- beaver dams
- bird's nests
For example, an apartment building is built so that people can have shelter.
Human-built structures can impact the environment in different ways:
Negative impacts-
-grass and farmland is destroyed
- the trucks that transport materials for building structures can pollute the air
- materials for building structures are sometimes taken out of the environment, for example from mines
Positive Impacts-
- some structures provide us with shelter and entertainment
- some structures bring money for the economy (ex. shopping malls)
- some structures provide us with electricity (ex. windmills give us windpower)
Animals built structures as well! They build structures for one of three reasons:
1. To create a protected home
2. To trap prey for food
3. To communicate to other animals of the same species
Some examples of animal structures include:
- beehives
- beaver dams
- bird's nests
FORCES that cause tension or compression to a structure can cause a DEFORMATION to a structure. This means that the structures will change because of the force. When planning to build a structure, we need to think about the forces that will act on the structure and then choose materials and use techniques that will help the structure not get a deformation.
COMPRESSION is a pushing FORCE. For example, if we smush a ball of clay down, or together in our hands, the ball of clay is in compression.
TENSION is a type of FORCE. It is a pulling force. For example, in a tug-of-war game, the rope is in tension.
Adding struts and ties to a structure can make the building more stable because:
Struts resist compression. This means that they make it so a load or force will not PUSH the structure down.
Ties resist tension. This means that they make it so a load or force will not allow the structure to be PULLED apart.
COMPRESSION is a pushing FORCE. For example, if we smush a ball of clay down, or together in our hands, the ball of clay is in compression.
TENSION is a type of FORCE. It is a pulling force. For example, in a tug-of-war game, the rope is in tension.
Adding struts and ties to a structure can make the building more stable because:
Struts resist compression. This means that they make it so a load or force will not PUSH the structure down.
Ties resist tension. This means that they make it so a load or force will not allow the structure to be PULLED apart.
Forces Review
Unit 2: Strong and Stable Structures
Important vocabulary for this unit:
Structure: a framework that supports a load. Structures can be human-built or animal built. Examples: a house, a skyscraper, a play structure, a table, a bird's nest, a beaver dam, etc. Anything that is built and made of different parts.
1. Draw examples of some different structures that you already know.
Load: the weight that a structure needs to hold. Examples: a building needs to hold all of the people and things inside of it. A play structure needs to hold the children that will play on it.
Building: a building is a type of structure. A building is a type of structure where people live, work, or store things. Examples: A school, an apartment building, a hospital... these are all examples of buildings.
2. Look on online or around you community for different structures. Choose one type of building that you like! Identify the load that this building needs to be able to hold. Remember, a load is not just one thing! Structures need to be built and be able to support everything inside of them, and also their own weight.
3. Draw a picture of the building. Label the following parts of the building:
- floor
- roof
- walls
- windows
- doors
3. Draw a picture of the building. Label the following parts of the building:
- floor
- roof
- walls
- windows
- doors
Forces in Nature Research
1. Click on the button below and watch some different videos.
2. Choose one force in nature from this list:
- earthquake
- avalanches
- landslides
- erosion
- tsunamis
- hurricanes (typhoons)
- tornadoes
- earthquake
- avalanches
- landslides
- erosion
- tsunamis
- hurricanes (typhoons)
- tornadoes
3. Use the videos below and your own research to complete the Forces in Nature Research Paper.
Earthquakes:
Avalanches:
Landslides:
Erosion:
Tsunamis:
Hurricanes:
Tornadoes:
Unit 1: Forces Causing Movement
We are learning about pushes and pulls.
- all forces are either a push or a pull
- can you think of some examples of a pushing force? a pulling force?
- can you think of some examples of a pushing force? a pulling force?
We are learning about the effects of forces.
Forces can cause an object to...
- start moving
- stop moving
- speed up
- slow down
- change direction
- change shape
- start moving
- stop moving
- speed up
- slow down
- change direction
- change shape
We are learning about different types of forces.
1. Gravity
- gravity is always a pulling force
- gravity pulls everything on the Earth towards the Earth
- when we jump up, we are pulled down by the force of gravity
- when we throw a ball, the ball will come down because of the force of gravity
- gravity is always a pulling force
- gravity pulls everything on the Earth towards the Earth
- when we jump up, we are pulled down by the force of gravity
- when we throw a ball, the ball will come down because of the force of gravity
2. Magnetic Force
- it can be a pushing or a pulling force
- magnets attract (pull) objects
- if you place the same poles (NN or SS) of two magnets next to one another, they will repel (push away) from each other
- it can be a pushing or a pulling force
- magnets attract (pull) objects
- if you place the same poles (NN or SS) of two magnets next to one another, they will repel (push away) from each other
3. Muscular Force
- we use muscular force to push and pull objects, to make them move or to make them stop, or to make them speed up or slow down
- our muscles pull on our bones which causes us to move
- we use muscular force to push and pull objects, to make them move or to make them stop, or to make them speed up or slow down
- our muscles pull on our bones which causes us to move
4. Electrostatic Force
- this can be a pushing or a pulling force
- when 2 objects have the same charge, they push away from each other
- when 2 objects have different charges, they are attracted to each other (pull together
- For example, if I rub a balloon on my sweater, I give it a a charge, so it will stick to (pull towards) an uncharged wall
- lightning is an example of electrostatic force
5. Friction
- friction in a pushing force. It is the force of two objects pushing or rubbing together
- friction in a pushing force. It is the force of two objects pushing or rubbing together