Practice Down. Danger. Dial. to stay safe around power lines and learn how to shuffle 10 metres to safety. Imagining a school bus as a guide, students will estimate, and measure 10 metres while learning that 10 metres is a safe distance to move away from a fallen or hazardous power line.
Assess students’ ability to shuffle 10 metres away from a downed power line, and estimate approximately 10 metre distance
Power lines are conductive meaning the electrical current runs through them with the least resistance. However if something makes contact with a live power line like a tree, kite, or ladder, the electrical current may flow to the ground. The place where the current touches the ground is the highest voltage and from that point the electrical current spreads out in irregular concentric circles. The voltage or electrical intensity decreases as it moves further from the source. A safe distance from the source of contact, like a downed power line, is 10 metres or more.
Electricity has the ability to find its way through touch to get to the ground. If a kite gets tangled in a power line, the electrical current could travel through the kite and you to reach the ground. Birds do not get zapped when standing on a power line, however they would if they straddled two power lines, or touch their beak to the ground while standing on the power line.
If there is a power line on the ground, you need to move away from the source (where it touches the ground). However electricity has the ability to move through your body as you step away from the source of electricity. As electrical current flows through the ground the voltage decreases in concentric rings or ripples as you move further from the source. So, if you move away by lifting one foot, the change in voltage between the concentric rings can travel up one leg and down the other. Instead by keeping your legs together and shuffling your feet, the electrical current will stay in the ground. 10 metres is the safe distance calculated based on the voltage in the power lines here in B.C.