Name of Activity | Detective Electrical Engineering |

Author | Hannah Garfield & Kirsten Jorgensen |

Keywords | detective, electrical, circuits, mystery, squishy circuits, short circuit, light bulb, museum |

Subject | Non-LEGO |

Grade Level | 4, 5 |

Time | 1 Hour Total |

Brief Description | 1st lesson in “Detective Engineer/Intro to Engineering Unit”
In this lesson the students will learn the basic concepts of circuits and what electrical engineers design. |

Lesson Objectives: | – understanding basic circuit – understanding short circuit – idea of what electrical engineers design |

Materials Needed: | – white board/black board and markers/chalk – play dough (1 tub per group) – 9 volt batteries (1 per group) – LED lights that work with squishy circuits (1 per group, but probably bring more) |

Procedure | Detective story: There was a break-in at the Museum of Science. Something valuable stolen or whatever you want to say (more details about break-in so it sounds believable). You (students) have been hired as the detective engineer on the case. You need to solve the crime using your engineering skills. Upon arriving at the crime scene you cannot see anything since the bomb/explosion/etc. disrupted the museum’s lighting system and all of the lights are off. Ask students what type of engineer they need to be to solve this step of the crime. (Eventually they get to electrical.) Discussion with students about what electrical engineers design. Introduce the basic idea of a circuit – idea that electrons are flowing through circuit to make light illuminate, for example. Break students into groups of 2 and distribute squishy circuit materials. Allow students some time to play on their own with trying to get the light to light up. After 5- 10 min or so, bring class back together and discuss what’s working and what isn’t. Draw a battery, clearly indicating + and – ends, and a light bulb, also with clear + and – ends, on the board. Ask for volunteers to complete the circuit and ask them/the class why they connected wires to what and where, etc. Someone will most likely draw a short circuit and if not draw one yourself. Ask students if this circuit would light up the bulb and why or why not. Students can also come up and in a different color illustrate where they think they electrons are going if that helps them understand/get their point across. Allow students to return to their groups and try to make the light bulb light up again. With about 10-15 min left of class, bring students back together. Have a complex-ish circuit (made of only batteries, wires, and light bulbs) drawn on the board. Intentionally draw some short circuits, some wires that don’t connect to anything, etc. Tell students that this is the museum’s lighting circuit system and ask them to tell you what’s wrong with it and why. Students solve the broken circuit and the lights go on in the museum! End of class. |

Extensions: | If students get the bulb to light up early, give them additional light bulbs to try to make those light up as well and/or design a switch (and have them figure out what that is). |

Umbrella Unit/Curriculum (if applicable) | Detective Engineer: Intro to Different Types of Engineering |

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Nazifa Sarawat and I used this activity as part of our detective engineering unit during Fall 2015 at JQS.

Instead of just talking about electrons and how they work in a circuit, we played a little game where the students were “electrons” in a circuit, and had to do jumping jacks when they reached a “resistor.” This illustrated the concept of electrons, current, and resistance, giving them the basic understanding that resistors can be used to reduce the current (speed) of electrons in a circuit. It was fun to get up and moving around instead of lecturing them on this concept, which can be very challenging for fifth grade.

We also mentioned conductivity, and discussed how some materials are better at transporting electrons than others. They came up with several conductive materials and insulating materials on their own that they were already familiar with. We led into distributing the play-doh by asking them if they thought it was conductive, and afterward discussed how salt in the play-doh affected its conductivity. For groups that finished early, we challenged them to investigate the conductivity of fruit, and gave out apples and bananas. They quickly discovered that they were conductive, so we discussed this as well.

We extended our study of electricity to a second week, in which we used snap circuits instead of squishy circuits. This week, we connected more to the storyline, suggesting that it was very dark at the crime scene, and it was really hot in the chasm where the van der Graaff generator had been removed. To help the officials investigating the scene, students designed circuits which would help light the area and circulate the air using fans. Many students figured out parallel circuitry would help light the bulb brighter and get more speed out of the fan. We briefly discussed this phenomenon and why it works at the end of class.