Search the California Content Standards

Standard:
Iteratively design and develop computational artifacts for practical intent, personal expression, or to address a societal issue by using events to initiate instructions.

Descriptive Statement:
In this context, relevant computational artifacts can include programs, mobile apps, or web apps. Events can be user-initiated, such as a button press, or system-initiated, such as a timer firing. For example, students might create a tool for drawing on a canvas by first implementing a button to set the color of the pen. Alternatively, students might create a game where many events control instructions executed (e.g., when a score climbs above a threshold, a congratulatory sound is played; when a user clicks on an object, the object is loaded into a basket; when a user clicks on an arrow key, the player object is moved around the screen).

Standard:
Describe ways in which abstractions hide the underlying implementation details of computing systems to simplify user experiences.

Descriptive Statement:
An abstraction is a representation of an idea or phenomenon that hides details irrelevant to the question at hand. Computing systems, both stand alone and embedded in products, are often integrated with other systems to simplify user experiences. For example, students could identify geolocation hardware embedded in a smartphone and describe how this simplifies the users experience since the user does not have to enter her own location on the phone. Alternatively, students might select an embedded device such as a car stereo, identify the types of data (e.g., radio station presets, volume level) and procedures (e.g., increase volume, store/recall saved station, mute) it includes, and explain how the implementation details are hidden from the user.

Standard:
Describe issues that impact network functionality.

Descriptive Statement:
Many different organizations, including educational, governmental, private businesses, and private households rely on networks to function adequately in order to engage in online commerce and activity. Quality of Service (QoS) refers to the capability of a network to provide better service to selected network traffic over various technologies from the perspective of the consumer. Students define and discuss performance measures that impact network functionality, such as latency, bandwidth, throughput, jitter, and error rate. For example, students could use online network simulators to explore how performance measures impact network functionality and describe impacts when various changes in the network occur. Alternatively, students could describe how pauses in television interviews conducted over satellite telephones are impacted by networking factors such as latency and jitter.

Standard:
Describe the design characteristics of the Internet.

Descriptive Statement:
The Internet connects devices and networks all over the world. Large-scale coordination occurs among many different machines across multiple paths every time a web page is opened or an image is viewed online. Through the domain name system (DNS), devices on the Internet can look up Internet Protocol (IP) addresses, allowing end-to-end communication between devices. The design decisions that direct the coordination among systems composing the Internet also allow for scalability and reliability. Students factor historical, cultural, and economic decisions in their explanations of the Internet. For example, students could explain how hierarchy in the DNS supports scalability and reliability. Alternatively, students could describe how the redundancy of routing between two nodes on the Internet increases reliability and scales as the Internet grows.

Standard:
Demonstrate the flow of execution of a recursive algorithm.

Descriptive Statement:
Recursion is a powerful problem-solving approach where the problem solution is built on solutions of smaller instances of the same problem. A base case, which returns a result without referencing itself, must be defined, otherwise infinite recursion will occur. Students represent a sequence of calls to a recursive algorithm and show how the process resolves to a solution. For example, students could draw a diagram to illustrate flow of execution by keeping track of parameter and returned values for each recursive call. Alternatively, students could create a video showing the passing of arguments as the recursive algorithm runs.

Standard:
Illustrate ways computing systems implement logic through hardware components.

Descriptive Statement:
Computing systems use processors (e.g., a central processing unit or CPU) to execute program instructions. Processors are composed of components that implement the logical or computational operations required by the instructions. AND, OR, and NOT are examples of logic gates. Adders are examples of higher-leveled circuits built using low-level logic gates. Students illustrate how modern computing devices are made up of smaller and simpler components which implement the logic underlying the functionality of a computer processor. At this level, knowledge of how logic gates are constructed is not expected. For example, students could construct truth tables, draw logic circuit diagrams, or use an online logic circuit simulator. Students could explore the interaction of the CPU, RAM, and I/O by labeling a diagram of the von Neumann architecture. Alternatively, students could design higher-level circuits using low-level logic gates (e.g., adders).

Standard:
Examine the scalability and reliability of networks, by describing the relationship between routers, switches, servers, topology, and addressing.

Descriptive Statement:
Choice of network topology is determined, in part, by how many devices can be supported and the character of communication needs between devices. Each device is assigned an address that uniquely identifies it on the network. Routers function by comparing addresses to determine how information on the network should reach its desgination. Switches compare addresses to determine which computers will receive information. Students explore and explain how network performance degrades when various factors affect the network. For example, students could use online network simulators to describe how network performance changes when the number of devices increases. Alternatively, students could visualize and describe changes to the distribution of network traffic when a router on the network fails.

Standard:
Explain how the characteristics of the Internet influence the systems developed on it.

Descriptive Statement:
The design of the Internet includes hierarchy and redundancy to help it scale reliably. An end-to-end architecture means that key functions are placed at endpoints in the network (i.e., an Internet user's computer and the server hosting a website) rather than in the middle of the network. Open standards for transmitting information across the Internet help fuel its growth. This design philosophy impacts systems and technologies that integrate with the Internet. Students explain how Internet-based systems depend on these characteristics. For example, students could explain how having common, standard protocols enable products and services from different developers to communicate. Alternatively, students could describe how the end-to-end architecture and redundancy in routing enables Internet users to access information and services even if part of the network is down; the information can still be routed from one end to another through a different path.