Hooked on Science: Pinecone hygrometer

Use a pine cone to test the air's humidity.

Materials

• Two pine cones
• Warm water
• Two widemouth Mason jars

Instructions

STEP 1: Fill one of the Mason jars with warm water.

STEP 2: Place one of the pine cones in the Mason jar with warm water.

STEP 3: Place the other pine cone in the Mason jar without the warm water, wait 15 minutes and observe.

Explanation

The pine cone in the Mason jar with warm water closes, while the pine cone in the Mason jar without the warm water stays open. Pine cones act as a natural hygrometer, which measures the amount of moisture in the atmosphere. Pine cones contain seeds, which are transported by the wind. Pine cones open their scales to disperse the seeds when the air is dry and close their scales when the air is moist, which keeps the seeds dry. Therefore, when a pine cone closes its scales, it's indicating a higher humidity, while a pine cone with open scales, indicates a lower humidity.