This document outlines how the activity might be linked to the NGSS as part of a classroom lesson.
This activity should only be conducted by an individual who is experienced working with electricity. Science Discipline(s) Physical Science Topics
- Physical properties
- Light transmission
- Energy Transitions
- Mechanical Pencil Lead (0.5mm and 0.7mm graphite)
- 8 D cell batteries
- Electrical Tape
- Insulated metal wire (battery to pencil lead, length as needed)
- Alligator Clamps (4x)
- Alligator clamp stand (optional)
- Heat/Electrical insulating gloves
- 1 Clear Glass Jar
- Attach 1 alligator clamp to each end of a length of wire. (Repeat 2x)
- Attach the 0.5 mm pencil lead to the alligator clamps in such a manner that it is sturdy, and will not move during the experiment, preferably use a stand, however, they can also be taped to the edge of a table such that the graphite will not burn anything when it gets hot.
- Don safety gloves, and attach ONE of the 2 wires to the battery/electrical source.
- After making sure that the graphite is in a safe position, and the audience is aware that it will soon get very hot, and be an exposed bare wire, attach the other wire to the battery/electrical source.
- The pencil lead should light up. Depending on the diameter of the lead, it may take a short amount of time so begin glowing, wait 5-10 seconds before resetting the experiment.
- When finished, DISCONNECT THE BATTERY, and then with thermally protective gloves, remove the pencil lead. It is hot and should be treated as such.
- Why did the lead glow?
- How could you test the effect of voltage and current (e.g., the number of batteries) on how brightly the lead glowed?
- What kinds of energy transfer is taking place (there’s more than 1)?
- Why was the thicker lead dimmer?