Question

data analysis

1. write a sentence that explains how soap affects the surface tension of water based on the results of your experiment
2. identify the independent (manipulated) variable and the dependent (responding) variable in your penny experiment
3. what was the control in the penny experiment? what is the purpose of this control?
4. what other questions can you develop (and even test) about surface tension. write at least two follow - up questions that could be tested using the penny technique.
5. consider the experimental question and how it relates to a water strider. what happens to water striders on lakes that have been contaminated with soap? make a claim to answer this question and support your claim with evidence from the experiment you conducted.

Explanation:

Step1: Answer question 1

Soap reduces the surface - tension of water.

Step2: Answer question 2

Independent variable: presence or absence of soap; Dependent variable: surface - tension related property (e.g., number of drops on penny).

Step3: Answer question 3

The control is the penny experiment without soap. Its purpose is to provide a baseline for comparison to see the effect of soap.

Step4: Answer question 4

1. How does the type of soap affect surface - tension? 2. Does the concentration of soap solution change the surface - tension more significantly?

Step5: Answer question 5

Claim: Water striders have difficulty walking on soapy water. Evidence: Soap reduces water surface - tension, and water striders rely on high surface - tension to stay afloat.

Answer:

1. Soap reduces the surface - tension of water.
2. Independent variable: presence or absence of soap; Dependent variable: surface - tension related property (e.g., number of drops on penny).
3. Control: penny experiment without soap; Purpose: provide a baseline for comparison.
4. How does the type of soap affect surface - tension? Does the concentration of soap solution change the surface - tension more significantly?
5. Claim: Water striders have difficulty walking on soapy water. Evidence: Soap reduces water surface - tension, and water striders rely on high surface - tension to stay afloat.