Name: ______Date: ______
Unit 1B. 2- Surface Tension and Density Demonstrations Period: ______
Activity 1:
1. Predict how many drops will go on the penny before it overflows. Write down the prediction number in the data table below.
2. Place the penny on a tray with a small piece of paper towel under the penny to facilitate observation of when the water overflows the penny.
3. Use a dropper to carefully place water drops, one at a time, on a penny.
4. Observe the number of drops that can be added before the water flows off.
5. Try again! See if you can get more drops on the penny the second time around.
6. Repeat steps 1-5 using a type of alcohol.
Water (H2O) / AlcoholPrediction
Trial #1
Trial #2
7. Draw the shape of the water and the penny right before it spilled over.
8. Which could hold more drops of liquid, the water or the alcohol?
9. Explain why to question 8.
Activity 2:
1. Obtain a paperclip, a beaker of water, and a strip of paper towel from your teacher.
2. Using those 3 objects try to paper clip to float on top of the water.
3. What method did you use?
4. Why did the paperclip float in the water?
Activity 3:
1. Write the equation for density below:
2. Find the mass of 20 mL of water. Record the mass below:
3. Determine the density of water. Show all work.
4. In the foul-water investigation (pg. 10), you observe that coffee grounds settled to the bottom of the water sample, whereas oil floated to the top. Explain this observation in terms of relative densities of coffee grinds, water, and oil.
5. How does the density of ice compare to that of liquid water? What evidence can you cite to support your answer. **Hint: Use everyday experiences to answer these questions*** What would happen to rivers and lakes (and fish)in colder climates if the relative densities of ice and liquid water were reversed?
6. Suppose you were given a small cube of copper metal. What measurements would you need to make to determine its density? How would you make these measurements in the laboratory?