First Name: ____________ Last Name: ____________ Student #: ____________ Group: _______

Surface tensionWhat is surface tension?

Surface tension is a really amazing thing that happens with some liquids. It’s a force that acts on the particles at the surface of a liquid. Surface tension makes some liquids form spherical (circle) shapes. Have you ever seen a dewdrop on a leaf in the morning? Have you blown soap bubbles and watched them float away? Surface tension makes it happen!

Let’s think about water surface tension. Water is made of two atoms of hydrogen and one atom of oxygen, H₂O. The hydrogen atoms have a small positive charge. The oxygen atoms have a small negative charge. Just like a magnet, positive and negative want to stick together. Water molecules LOVE to stick to other water molecules!

When the molecules stick together very tightly, it’s like a thin “skin” forms on the surface. It’s like the skin of a balloon, but much, much thinner.

To do: Take out the coins from the previous experiment and dry them off!

Fill your cup until it is completely full again.

Get your paper clips ready!

Your GOAL!

You CAN make a paper-clip float on water. How??

Could you float all of your paper clips on the water at the same time?

What happens to the paper-clips if the surface tension breaks?

Can the paper clips still float if they are wet?

To do: Fill your cup until it is completely full. The water should be perfectly flat across the top of the cup!

Get coins out of your wallet.

Question: How many coins do you think you can put in the cup before the water spills over?

Write your GUESS here:

The EXPERIMENT!!

Time to try it. Gently start putting coins in 1 by 1. How many could you fit?

How close was your guess to the true number??

A) I’m perfect!B) Meh...Pretty close!C) Wow...I was totally wrong!

To do: Get out the penny!

Get out your straw!

Look at your straw. Draw a mark at .5cm, 1cm, 1.5cm, and at 2cm. If you put your straw in the water and put your finger over the end of the straw, you can pick up water. Practice this a little.

Question! How many “straw centimeters” of water will fit on the penny without spilling over?Write your GUESS here:

The EXPERIMENT!!

Time to try it. Gently start adding water to the top of your penny How many centimeters could you fit?

How close was your guess to the real amount?

A) I’m perfect!B) Meh...Pretty close!C) OMG!...I was waaaay wrong!

Ok, clean up time!

1) Pour the water in the sinks.

2) Dry the dishes and coins.

3) Put everything away properly.

Thank you!!!

Lab Work Finished!

1. surface tension__________2. liquid__________3. force__________4. spherical__________5. dewdrop__________6. leaf__________7. float away__________8. atom__________9. hydrogen__________10. oxygen__________11. molecule__________12. positive charge__________13. negative charge__________14. magnet__________15. spill over__________16. experiment__________17. gently__________18. wet__________19. tightly__________20. amount__________

A)漂う

B)力

C)水素

D)液体

E)葉っぱ

F)負電荷

G)球状の

H)優しく

I)原子

J)実験

K)表面張力

L)濡れている

M)酸素

N)分子

O)こぼれる

P)しっかり

Q)露の玉

R)量

S)正電荷

T)磁石

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?