Caves and Sinkholes

What You'll Learn

Sinkholes form when underground limestone dissolves, leaving a cavity that collapses. They are common in areas with karst topography where water slowly dissolves the bedrock.

Key Words

evaporation
condensation

Materials Needed

water
plastic tray
magnifying glass

Safety First

Do not taste any materials.
Wear safety goggles when mixing liquids.

Steps

Step 1 — Read

Look at the vocabulary words and write a definition for each in your own words.

Step 2 — Do

Test rock hardness using Mohs scale: try scratching rocks with your fingernail, a penny, and a nail. Rank them from softest to hardest.

Step 3 — Observe

Compare the before and after states.

Step 4 — Record

Write your conclusion: did the results match your hypothesis? What would you change next time?

Check Your Understanding

Question 1

1 of 3

What causes ocean tides?