1. Types of Structures
1.1. Solid: Strong structures that are often large masses. It is made up of sturdy materials such as concrete which can result in a very stable and long-lasting structure.
1.1.1. A Book
1.1.1.1. Books are very strong, no matter if they are hard or soft covers. Books with hard covers are good because they aren't easily bent.
1.1.2. Bricks
1.1.2.1. These solid structures are able to make other structures. They're heavy enough to withstand all kinds of weather.
1.2. Frame: They support a building or structure by creating a base that holds up the rest. A frame structure may seem fragile, but they are built to hold up the large or small mass on top of it. In some cases, some structures may just have the frame.
1.2.1. The Eiffel Tower
1.2.1.1. The Eiffel Tower is a frame structure that is very stable even though it is very large and tall. There is no "membrane" stretched over it, but it is a good example of how strong a frame structure can be
1.2.2. Tent
1.2.2.1. The frame of the tent would be the metal bars that would support the fabric that is over it. Frames are not as easily broken as one might think at first; in this case, the bars are the only things keeping the tent from collapsing.
1.3. Shell: These structures are curved shaped and hollow like a bike helmet. An advantage of a shell structure is that, though it is light, it is still a very strong and stable structure.
1.3.1. Igloo
1.3.1.1. An igloo is a shell structure because it is, in most cases, round. It is also hollow inside yet it can still withstand strong wind.
1.3.2. Helmet
1.3.2.1. It is hollow to allow your head to fit in, but is still sturdy enough to protect you. from something like falling on to the ground.
1.4. Combination: Made from a variety of structures like shell, solid and frame structures.
1.4.1. A Desk
1.4.1.1. The legs of the desk are the solid structures, while the actual desk is a shell structure. This is because there is a hollow opening that stores things.
1.4.2. Car
1.4.2.1. It uses a frame structure to hold it up; with solid structures inside such as the car seats.
1.5. Overall, these are just different types of structures; but, what's really important is whether they can support their own weight and more. If a table couldn't hold some heavy objects, it would break and collapse.
2. Types of Loads
2.1. Static Loads: They are split/composed of two components.
2.1.1. Dead Load: It is a force that does not change. For example, a certain structure may have something attached to it that cannot be taken off; and so the dead weight will always affect it.
2.1.1.1. Gears and other features on a bicycle
2.1.1.1.1. Gears that are attached to bicycles are putting weight on it.
2.1.1.2. The Bicycle Itself
2.1.1.2.1. Dead weight could also just be the weight of the object itself; caused by gravity
2.1.2. Live load: This type of load is only temporary; an example is a human. They put weight on a structure with gravity and their weight, that is why two people can affect the same structure differently. One person may have a smaller or larger mass; so they'll weigh differently.
2.1.2.1. People in a Subway
2.1.2.1.1. An example of live load is the people walking in and out of the subway. They may be a load while on the subway, but as they leave, their weight no longer affects it.
2.1.2.2. Groceries
2.1.2.2.1. Groceries of different weights are live loads; there may be heavy objects inside such as potatoes, or lighter objects such as grapes.
2.2. Dynamic Loads: Indirect forces such as wind that affect how the structure moves and reacts.
2.2.1. Wind
2.2.1.1. Wind is a dynamic load that could affect an object or building by pushing against it.
2.2.2. Water
2.2.2.1. Water can move a structure and can affect with a certain amount of force. The force could be strong enough to destroy or damage something like a building
3. Application of Forces
3.1. The point of application is where you apply a certain amount of force to an object. Where you apply the force affects the structure differently
3.1.1. Punching the punching bag with a high magnitude (a lot of force), directly.
3.1.2. Kicking a ball requires a high magnitude for a stronger force, and will go different ways depending on where you apply the force.
3.2. The plane of application is the angle a force affects to the structure.
3.2.1. Hitting from the front, 90 degrees.
3.2.2. Hitting a tennis ball from different angles.
3.3. Three boxes on top of each other. The point of application could be the bottom, while if the top box was hit, it would cause different damage. The angle of application could be 45 degrees, but the structure would react differently if it was 90 degrees.
3.3.1. Pushing the boxes from the top
3.3.2. Pushing the boxes from the middle
3.4. The direction could be pushing or pulling, it's the way forces pass through the object. You could push an object to the right, or pull it to the left; or the other way around.
3.4.1. The boxes are being pushed away
3.4.2. Pulling something towards you
4. Purpose, Form and Function
4.1. The purpose of a structure is what it is used for. They could transport people or goods, give shelter ,etc.
4.1.1. Vehicles are used to transport.
4.1.2. Kitchen stoves, microwaves and toasters are used to prepare food.
4.2. Form is the kind of structure it is and the way it is built depending on the purpose or function.
4.2.1. A car is designed the way it is to perform its tasks.
4.2.2. A cell phone is built to be portable yet useful.
4.3. Function is how a structure works and what depends how the actual structure looks like.
4.3.1. Engines make sure that the vehicle works and takes up space.
4.3.2. Wheels play a part in a structure and what it is used for.
5. Internal Forces
5.1. Torsion: Internal forces of twisting acting in an object. A result of applied this force, it may be broken if you use more forces.
5.1.1. Torsion makes a material to turn around and around which could make it narrower at the center.
5.2. Compression: An internal force that make many pressure to acting in an object. Then inside the object the particles will move closer together.
5.2.1. Compression on an object causes it to become more compressed or closer together due to the weight on top.
5.3. Shear: Forces acting in an object. Such as when you pushes/pulls the object into opposite directions, as a usually result it will rips or tears of the object.
5.3.1. Breaking something with the force called shear.
5.4. Tension: An internal force. If I use many forces to pulling the particles of an object apart. As a result it will broken into two parts.
5.4.1. This force means to pull something from two sides, causing the material to stretch or break.
6. External Forces
6.1. Gravity: It's a non-contact force. When you play with a ball, the ball dropped on the ground. There have the gravity between there. It attract the ball towards the ground. objects will fall at the same time with the exception of a feather even with different masses.
6.1.1. Gravity pulls things down.
6.2. There are many examples of the external force in the real world. Like the wind and earthquakes. Cause the forces like these are act on buildings. (The force in the direction opposite to gravity is also the external force.)
6.2.1. A push is to make an object go farther from you while a pull is making an object come coser.
6.3. Applied forces: When you sleeping on a bed, gravity pulls down on you. But you are not fall, because the bed applies a force on you. The downward force equals the upward force of the magnitude. So the person who is sleeping on the bed didn't fall down.
6.3.1. Another example, pushing or puling a door depending which side you are on.
6.4. Overall, an external force is a push or a pull.
7. Center of Gravity
7.1. Structures tend to be more stable if its center of gravity is low, rather than high. The reason behind this is, if your center of gravity is lower, it is closer to the ground; therefore, it is more stable and less likely to topple over.
7.2. You know that an object or structure has a low center of gravity if the base is more broad and heavy. Structures that are smaller at the base will tend to be very wobbly and fall down.
7.3. If we didn't have center of gravity. We would not be stable when walking or running.
7.4. A pyramid is a good example of a structure with a wide base and low center of gravity. Its base has a larger, wider base compared to the narrow top., ensuring that it is very stable.
7.5. This glass would be easy to tip over because its center of gravity is higher up.
8. Part 2: River Dams
8.1. Purpose: River dams are used to make sure that floods are stopped and to reserve water to store and be distributed and given to other locations. They are also used as a source of water to generate energy. It divides large bodies of water from smaller ones.
8.1.1. Another example of a river dam.
8.2. Form: Its form is tall and is built with strong materials so it doesn't break from the water.
8.2.1. Made sure to be able to withstand water.
8.3. Function: the dam takes the energy and force from the water and turns it into electricity. It stops tides of water from flooding.
8.3.1. Hydro energy
8.4. River dams are solid structures using strong materials to withstand the water.
8.4.1. Solid structure
8.5. Some ways external forces can affect the dam is firstly, the water pushing against it. Another way is just the structure itself, with gravity pushing down on it.
8.5.1. Internal forces that can affect dams are: compression from the structure itself. If a dam is not strong enough, it could be affected by shear, being broken apart, because of the water.
8.6. A river dam doesn't very many different kinds of loads; but, a live load it carries is mostly water, while the dead load is itself. The dynamic load could be the water as well since it is still affecting it, like the wind.
8.6.1. The dam itself is the dead load.
8.7. The center of gravity is often the bottom since it has a larger mass and is wider there to keep it stable so it isn't easily broken. If a river dam had a higher center of gravity, the structure would likely collapse from the force of water that it has to keep separated.
8.7.1. River dams with a larger base are stronger.