Activity

Electric circuits with home-made wires and bulbs

Summary
Clip bulbs and wires from holiday light strings, or make wires from foil and masking tape. Students freely experiment with the lights, wires and batteries, using masking tape to connect them. Students learn how to set up an electric circuit and understand how electricity flows in a circuit. Also good for energy transformations.
Science content
Physics: Energy forms, Conservation of Energy (1, 3, 4, 5)
Physics: Electricity, Electromagnetism (7)
Materials
  • aluminium foil (or use wires clipped from holiday light strings, or use purchased wires)
  • masking tape
  • holiday light bulbs, clipped individually from the strand, and the wire ends stripped (students can learn how to do this) Note: as wire ends get worn, clip and twist again, to make sure thin single wires are not carrying all the current (which will heat up and possibly cause burns)
  • 1.5V batteries
  • wire cutters and wire strippers
Procedure

This is a good free play activity. See the Play-Debrief-Replay method of teaching in the resource.
Note: please read about the short circuit possibility under Phenomena below, and stop them before the battery and wire gets too hot.

Optional: discuss with students what electricity is (a flow of electrons through a wire or something that can allow them to move in it). Ask them to think about this concept as they experiment. Use this concept as phenomena are explained later.

Show students their materials: battery, bulb, wires, clips and tape.

For Ks show them how to build a simple circuit with two wires, a battery and a bulb, and allow all to succeed before adding more components.

For all other students:
Show students how to how make more wires as follows: Tear off a length of foil from the roll. Make lengths of masking tape the width of the foil, and tape them next to each other to fill one side of the foil. Tear between the strips of tape, to make lengths of foil backed with tape.
Alternatively, clip wires from a string of holiday lights, or use purchased wires.

Show students how to make circuits by taping wires and bulbs to the desk, making sure there is a good connection between the metals of each.
Optional: show students how to clip bulbs from holiday lights (and long insulated wires if they wish to use these instead of the foil wires).

Start free play.
(Watch for short circuits: students bridging the ends of the battery with only the wire. The wires and the battery will get hot when a lot of current passes through them. Stop students from holding a short circuit configuration for more than a couple of seconds.)

Once students have experimented for a while ask them to leave their materials, and gather to discuss what they find.
Discuss electricity concepts as students come up with them. Encourage discussion between students about what they found.
Start to use symbols for circuit components.

Phenomena likely to come up, and terminology for them:
Short circuit, when a battery is connected by a wire at both ends, with no bulb. The current can flow fast between the ends of the battery, until the wire and the battery gets hot. Do not let short circuits run for very long.
Lighting the bulb: they will have found that they need to make a circle, containing a battery and a bulb to make the bulb light. Discuss that the electrons flow from one end of the battery (the negative) around the circuit and into the other end of the battery (the positive). If there is no circle, there will be no current and the bulb will not light. Students may experiment with number of batteries and numbers of bulbs.
Series circuit: when the battery and bulbs are all in a line. The energy from the battery is divided between the bulbs, so the brightness of the bulb will depend on how many batteries and bulbs there are.
Blowing a bulb: with a lot of batteries (at least 5) and one bulb the bulb will blow, as too much current flowing through it melted the element and broke the circuit.
Switch: students will find that some bulbs go on and off as they move the wires around. The contact is being broken, which breaks the circuit. Real switches break the circuit in a more controlled manner.
Parallel circuit: when there is more than one path for the current to flow, most simply with two bulbs straddling one battery. The brightness of the bulbs should be the same as when there is just one bulb, as each bulb will draw as much current as one alone when they are in parallel (unlike when they are in series).

Help students come up with new experiments to investigate more deeply (suggest students with similar questions work together).
If they have not already changed numbers of batteries and bulbs, encourage them to do so.
If they have not already made different shapes of circuits (series and parallel), encourage them to do so.

Regroup once more to share discoveries.
Encourage students to continue at home, as the materials are easy to obtain.

Notes

I am replacing the foil-and-tape wires with insulated wires cut from holiday light strands - the insulation means that wires can cross on students' desks without short circuiting.
I initially used clothes pegs to connect the wires and bulbs, but taping them together on a desk makes the circuit layout more clearly laid out, and makes bad connections less likely.

Grades taught
Gr K
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7