Cork is one of the most buoyant natural materials on earth, but just how buoyant is it? In this experiment, our goal is to determine how much weight a wine cork can hold while still floating. Our secondary question is whether natural and agglomerated wine corks have different results.

Age Recommendation: 4+ with adult supervision.

Materials List:

Wine Corks (New or Recycled)
Food Scale
Thumbtacks (heavier metal thumbtacks will require fewer thumbtacks)
Medium or Large Bowl of Water
Notebook
Pen or Pencil

Experiment Protocol

Step 1: Gather materials
Step 2: Create a chart in the notebook to record the results
Step 3: Weigh and record in the chart the starting weight for one wine cork (weigh the natural wine cork and the agglomerate wine cork separately)
Step 4: Place the wine cork in the bowl of water and record observations in the chart
Step 5: Weigh and record the weight of a thumbtack
Step 6: Place the thumbtack in the wine cork
Step 7: Place the wine cork with thumbtack(s) in the bowl of water and record observations in the chart
Step 8: Weigh the wine cork with thumbtack(s) and record the results in the chart

** Repeat Steps 5-8 until the wine cork is completely submerged **

Wine Cork Fully Submurged with Thumbtacks

Step 9: Tally the final weight of the thumbtacks you recorded in your chart. (This is the amount of weight that will sink the wine cork) Subtract the final thumbtack. (This is the amount of weight the wine cork can hold and float).
Step 10: Repeat steps 1-9 for the second wine cork
Step 11: Compare the weight of the thumbtacks to the original weight of the wine cork. Are they more, less, or the same? Are the results different for the natural wine cork and the agglomerate wine cork?
Step 12: Summarize results