The aim of this easy experiment is to determine which battery terminal is positive.
Things Required:
Aluminium foil
D-cell battery
Potato
2 paper clips
2 pennies
Steel wool
Masking tape
Scissors
1 push tack
Directions:
Cut a piece of aluminium foil 24 inches × 12 inches (60 cm × 30 cm). Fold the aluminium piece in half lengthwise five times to form a thin strip 24 inches (60 cm) long. Cut the aluminium strip in half to form two 24 inches (30 cm) strips.
Rub the pennies with the steel wool to clean them. Wrap the free ends of the aluminium strips around the pennies. Leave about half of each penny exposed. Secure the tape to the pennies with paper clips.
Ask an adult to cut the potato in half. Insert the edge of the pennies about 1/2 inch (1 cm) apart into the sliced part of the potato, being careful to keep the aluminium strips attached.
Use the tack to mark the position of the penny connected to the positive end of the battery.
Remove the pennies after one hour. Examine the holes made by the pennies.
This Is What Happens:
The hole around the penny connected to the metal tape leading to the positive terminal is green.
Science Behind It:
Connecting the penny to the positive pole of the battery gives the copper in the penny a positive charge. When the positively charged copper particles combine with negative particles in the potato, a green copper compound is formed. You can use this experiment to identify the positive terminal of any battery.
