Biology 1.04.docx - Controlled variables new penny dropper Procedure First I will put the pennies on a clean flat surface I fill the dropper with the

# Biology 1.04.docx - Controlled variables new penny dropper...

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Biology: Brian Cernoch Title: Surface tension property of water compared to soapy water Question: How adding soap to water changes the surface tension. I am going to use two different substances, water, and soapy water, to compare surface tension. I will observe which substance will spill over first and which substance will hold most drops on the penny. We know that one of water’s properties is a surface tension demonstrated by molecules bonding together and staying together. Adding soap to the water should disturb these bonds and cause more spillage or overflow. Hypothesis: What will happen when we drop different substances on the surfaces of the penny with the head facing up? I would assume that water because of its strong bonds between molecules will stay together the longest before spillage occurs. The soapy water might spill over sooner. Variables: Independent variables: water, soapy water, Dependent variables: amount of droplets of given substance

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Unformatted text preview: Controlled variables: new penny, dropper Procedure: First I will put the pennies on a clean flat surface. I fill the dropper with the different substances and start individually dropping them on the surface of the penny and count how many drops will stay on the penny for each substance. I will repeat the same experiment about 3 times for each substance, since it is somewhat hard to control the size of the drops. Data: Drops of Tap Water: Trial 1:9Trial 2:20 Trial 3:20 Average: 19.666 Drops of Soapy Water: Trial 1: 10Trial 2:9 Trial 3:9 Average 9.33 Conclusion and analysis: I found out that the added soap to the water reduced the surface tension because there were fewer droplets that would stay on top of the penny before spilling over. From this finding I can conclude that plain water has the greater surface tension for these 2 substances....
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