Surface tension lab 2012

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    06-May-2015
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Transcript of Surface tension lab 2012

  • 1.First Name: ____________ Last Name: ____________ Student #: ____________ Group: _______ Surface tensionWhat is surface tension?Surface tension is a really amazing thing that happens with some liquids. Its a forcethat acts on the particles at the surface of a liquid. Surface tension makes someliquids form spherical (circle) shapes. Have you ever seen a dewdrop on a leaf in themorning? Have you blown soap bubbles and watched them oat away? Surfacetension makes it happen!Lets think about water surface tension. Water is made of two atoms of hydrogen andone atom of oxygen, HO. The hydrogen atoms have a small positive charge. Theoxygen atoms have a small negative charge. Just like a magnet, positive and negativewant to stick together. Water molecules LOVE to stick to other water molecules!When the molecules stick together very tightly, its like a thin skin forms on thesurface. Its like the skin of a balloon, but much, much thinner.

2. To do:To do: Fill your cup until it is completelyTake out the coins from the full. The water should be perfectly previous experiment and dry them at across the top of the cup!off! Get coins out of your wallet. Fill your cup until it is completely full again.Question:How many coins do you think youGet your paper clips ready!can put in the cup before thewater spills over?Your GOAL!Write your GUESS here:You CAN make a paper-clip oat onwater. How??Could you oat all of your paper clipson the water at the same time?The EXPERIMENT!!Time to try it. Gently start puttingWhat happens to the paper-clips if thecoins in 1 by 1. How many could you surface tension breaks?t?Can the paper clips still oat if theyare wet?How close was your guess to the truenumber??A) Im perfect!B) Meh...Pretty close!C) Wow...I was totally wrong! 3. To do:How close was your guess to the real Get out the penny! amount?Get out your straw! A) Im perfect!B) Meh...Pretty close! Look at your straw. Draw a markC) OMG!...I was waaaay wrong! at .5cm, 1cm, 1.5cm, and at 2cm. If you put your straw in the water and put your nger over the end Lab Work Finished! of the straw, you can pick up water. Practice this a little.Question! How many straw centimeters of water will t on the penny without spilling over?Write your GUESS here:The EXPERIMENT!!Ok, clean up time!Time to try it. Gently start addingwater to the top of your penny How1) Pour the water in the sinks.many centimeters could you t?2) Dry the dishes and coins. 3) Put everything awayproperly.Thank you!!! 4. 1. surface tension__________ 2. liquid__________ 3. force__________ A)K) 4. spherical__________ 5. dewdrop__________B) L) 6. leaf__________ C)M) 7. float away__________ 8. atom__________ D)N) 9. hydrogen__________ E) O) 10. oxygen__________ F) P) 11. molecule__________ 12. positive charge__________ G) Q) 13. negative charge__________ H) R) 14. magnet__________ 15. spill over__________I)S) 16. experiment__________J)T) 17. gently__________ 18. wet__________ 19. tightly__________ 20. amount__________1) What kind of atoms are in water?2) Does a hydrogen atom have a positive charge or a negative charge?3) Why do water molecules stick together?4) What happens on the surface of the water when water molecules stick together?5) What is 1 new thing YOU learned today?