Surface Tension

© The Science Duo, LLC

•

Water is a colorless, odorless,
and tasteless liquid at room
temperature

•

It is known as the “universal
solvent” which means it can
dissolve a wide range of
substances

•

Water is able to store a large
amount of heat energy which
helps to regulate Earth’s
climate

•

Water makes up approximately
60% of the adult human body

• The tendency of water molecules to stick

together due to the force of attraction
between them

• Responsible for the formation of spherical-

shaped water droplets

• When water molecules are attracted to each

other, they minimize their surface area by
forming spherical droplets

• Cohesion is the reason why raindrops are

spherical in shape

Cohesion Examples

Dew drops
on leaves

Formation

of raindrops

Water

droplets

Multiple Choice

When water molecules stick easily to other water molecules, this is called what?

• cohesion
• adhesion
• solution
• polar molecule

Multiple Choice

What two elements make up water?

• Helium and oxygen
• Hydrogen and oxygen
• helium and carbon
• oxygen and carbon

Multiple Choice

Which of the following is an example of COHESION?

• water sticking to water

• water sticking to glass

• oil sticking to plastic

• hydrogen sticking to oxygen

• The ability of water molecules to stick to

other surfaces or materials

• Essential in water uptake in plants - allows

water to climb against gravity in narrow
tubes, like in the xylem of plants

• Causes a meniscus to form in a graduated

cylinder as water clings to the glass or
plastic wall

• Causes water to “wet” certain surfaces as

water spreads outs across the surface

​capillary action

Adhesion Examples

Meniscus
formation

“Wetting” of

a surface

Water uptake

in plants

O

H

H

Multiple Choice

Water's ability to stick to glass is

• adhesion

• cohesion

• surface tention

• capillary action

Open Ended

Explain the difference between cohesion and adhesion.

• A measure of how difficult it is to break the

surface of a liquid

• The force that acts on the surface of a liquid

• Water has a high surface tension due to the

cohesive forces between its molecules

• The high surface tension of water allows

small objects to float on its surface (i.e.
small paperclip, leaf, etc.)

Surface Tension Examples

Leaf floating

on water

Insects walking

on water

Water drops
on a penny

Multiple Choice

A measure of how difficult it is to stretch or break the surface of a liquid

• Cohesion

• Adhesion

• Surface Tension

Multiple Choice

An attraction between molecules of different substances

• Cohesion

• Adhesion

• Surface Tension

Multiple Choice

Why does water move from the roots to the leaves of plants?

• Water is pushed by solutes
• Capillary action pulls the water molecules like a chain
• Water is pulled by gravity
• Water’s cohesion causes it to “pull” towards the leaves

Multiple Choice

Attraction between molecules of the same substance

• Cohesion

• Adhesion

• Surface Tension

Multiple Choice

Water droplets take a spherical shape (as pictured) because of ____________

• adhesion
• cohesion
• capillary action
• solubility

Multiple Choice

Which characteristic of water will allow a paperclip to remain floating on water when the paperclip is gently placed on top of the water?

• adhesion
• surface tension
• solvent properties
• nonpolar

Multiple Choice

Water beads up on the surface of a penny because of this property.

• Adhesion
• High Surface Tension
• Universal Solvent
• Changes in Density

Multiple Select

Surface tension is the property of water in which...

• water molecules at the surface tend to stick together.

• water spills easily.

• water tends to be see-through.

•

5 checkpoint questions

•

Discuss each question with a partner

•

Write a complete answer to each
question on your notes page

Identify an
example of

cohesion that you
observe on a daily

basis.

Identify an
example of

adhesion that you
observe on a daily

basis.

Identify an
example of

surface tension
that you observe
on a daily basis.

Explain why a

meniscus forms

when measuring a

liquid in a

graduated cylinder.

Have you ever

“belly-flopped” into
a pool? Explain why
it hurts and makes a

loud sound.