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Teacher Toolbox icon Teacher Toolbox - The Purpose of this Reading

This STEM Lab focuses on programming the robot to respond to the conditions it detects. This first reading is intended to introduce the idea of conditionals, boolean (TRUE or FALSE) conditions, and the benefit of including these programming structures within a project. Students should begin to recognize that including conditional programming improves how the robot responds to its environment.

While watching a robot, it might seem to be making decisions about its own behavior but within the programming, it is checking on conditions and taking action appropriately. Students could consider how conditions influence their own informed decisions.
Decision to be made: Should I take an umbrella?
Current condition: It is likely to rain (TRUE).
Decision: Take an umbrella.

Standing at the base of a forked decision path. To the left is an arrow reading False and to the right an arrow reading True.
TRUE and FALSE paths

Decision Making

At their most basic level, programs are written to accomplish simple sequences of behavior. For example, you might want your robot to drive forward and also make some turns to reach a destination. But, what if you want your robot to wait for the right time to start driving forward and complete its route? That would require programming with conditional statements. You would use a conditional statement to define what the "right time to start" is within your project. Maybe the "right time" is after a button is pressed or when a sensor detects a specific level and then it starts driving. When you watch the robot's behavior, it will seem like it is deciding when to start driving but it's because you set the condition for when driving should start.

Conditional statements are powerful programming statements that use a boolean (TRUE or FALSE) condition and allow you to develop projects that have the robot behave differently depending on what it senses.

In the following example, if the Brain Up button is pressed (TRUE) the robot will drive forward. If the Brain Up button is not pressed (FALSE) the robot will stop driving. This shows the robot only driving forward when the Brain Up button is pressed, otherwise the robot stops.

VEXcode IQ project with a When started block and a forever block attached. Inside the forever block is an If then else block that reads If brain Up button pressed then drive forward, else, stop driving.

Extend Your Learning icon Extend Your Learning

To expand this activity, ask your students to pair up into teams and create a sketch of a maze for another team to complete. The maze should require a minimum of three to five conditional statements. For example, continue forward until there is a wall. Then, turn left. The students should write a solution to the maze in flowchart form. Students should then trade mazes with another team who should, in turn, create a solution to the maze in flowchart form. The two teams should then compare answers to see how closely they match.

To relate this activity to online or mobile games, ask your students to describe the goal of their favorite game/app. Then have students create a flowchart that outlines the first ten yes/no or true/false decisions that they follow in their game.