Quiz  /  Surface tension Class 9 MCQ Questions With Answers

  • 1. 
    In this experiment, what was the independent variable?

  • number of drops
  • number of trials
  • the penny
  • type of water (soapy or not)

  • 2. 
    In this experiment, what was the control group?

  • water with soap in it
  • water without soap in it
  • the penny
  • number of drops

  • 3. 
    Look at your data table where you recorded the number of drops that would fit on the penny. Which type of water has a higher average number of drops?

  • Tap Water
  • Soapy Water

  • 4. 
    In this experiment, what was the dependent variable?

  • number of drops
  • number of trials
  • the penny
  • type of water (soapy or not)

  • 5. 
    Surface tension is best described as

  • the ability of water molecules to stick to surfaces.
  • an unequal sharing of electrons between the oxygen and one hydrogen of a water molecule.
  • the ability of water molecules to dissolve many different chemical compounds.
  • a strong attraction between water molecules at the water’s surface.

  • 6. 
    ) If you were to investigate the effect of sugar on the surface tension of water, which approach would be the best way to conduct your experiment?

  • Dissolve sugar in water and drop it on a penny; count the number of drops before it spills over. Use the same sugar water mixture to repeat the experiment for a total of five trials.
  • Put sugar on a penny and drop tap water onto the sugar; count the number of drops before it spills over. Repeat this procedure for a total of five trials.
  • Drop water onto a penny until it forms a thick layer, then drop sugar grains into it until it spills over. Repeat this procedure for a total of five trials
  • Dissolve sugar in water and drop it on a penny; count the number of drops before spills over. Repeat the experiment for a total of five times, mixing a different amount of sugar into the water each time.

  • 7. 
    Read each statement below. Choose the statement that WOULD NOT be a correct hypothesis for a student to write for this experiment.

  • If I add soap to tap water, then more drops will be able to fit on the surface of a penny.
  • If I drop both tap water and soapy water on a penny, then more drops of the tap water will be able to fit.
  • If I count the drops of water that will fit on a penny, then the amount of soap in the water will increase.
  • If I add soap to tap water before dropping it on a penny, then the number of drops that fit on the penny will decrease.

  • 8. 
    Why was it important for you to take the average of several different trials in this lab?

  • in order to practice counting.
  • to make sure a single outlier or mistake doesn’t affect your overall conclusion
  • because this is the dependent variable in the experiment
  • because this is the independent variable in the experiment

  • 9. 
    What is your initial observation in this lab?

  • how many drops of tap water fit on a penny
  • how many drops of soapy water fit on a penny
  • what happens when you add soap to tap water

  • 10. 
    How does soap affect the surface tension of water?

  • Soap increases surface tension, so more soapy drops fit on the penny than drops of regular tap water.
  • Soap decreases surface tension, so more soapy drops fit on the penny than drops of regular tap water.
  • Soap increases surface tension, so fewer soapy drops fit on the penny than drops of regular tap water.
  • Soap decreases surface tension, so fewer soapy drops fit on the penny than drops of regular tap water.
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