Lab Report 3-24-09

Elise Gonzales! Ms. Hawthorne(: Science March 24, 2009 How many drops or water can fit on a penny? Take a Guess: How many drops of water can fit on one side of a penny: 16 Control Group: What did you keep the same? Water & penny Independent Variable: What did you change? What were you using? eye dropper Dependent Variable: What were you measuring? amount of water drops Materials: penny eye dropper cup water paper towels Procedure: Step 1: Rinse a penny in tap water and dry completely. Step 2: Place the penny on a paper towel. Step 3: Fill a dropper with water & practice dropping one drop at a time into the cup. Step 4: Hold the dropper vertically about one centimeter above the penny in order to place drops of water on the penny one by one. (One centimeter is about the size of your pinky nail) *Sometimes a steady hand can make more drops fit on the penny. A bump of the table can reduce the drops. We should do a few tests to get an average to see how many drops fit on a penny. Step 5: Record the number of drops for that trial in the table. Step 6: Repeat for all trials & find the average number of drops. Data: Test 1 18

Test 2 15

Test 3 28

Test 4 32

Average 23

Analyze & Conclude: 1. My Hypothesis is close to being correct. 2. Surface Tension is the property of water that allowed the water to remain on the penny. 3. No, the drops didn’t stay separated as they dropped on the penny, because the molecules are pulling on each other. 4. No, the water wasn’t flat on the penny because the pulling forces the surface into a curved shape.