Investigating Static Forces
in Nature:
The Mystery of the Gecko
Physical Science
Lesson 5
What Types of Forces Can Hold Objects
Together?
What Types of Forces Can Hold Objects
Together?
1
© 2009 McREL
What Sticks?
You will be working at several stations using an
assortment of materials to test and record some
ways that objects adhere to a plastic
transparency.
Try the suggested procedure described at each
station first before exploring on your own.
What Types of Forces Can Hold Objects
Together?
2
© 2009 McREL
What Sticks?
Station Materials
1
Magnets,
Paperclips,
Plastic
Transparency
2
Suction Cups,
Plastic
Transparency
3
Fur or Wool,
Balloon, and
Plastic
Transparency
Which Objects
Stick Together?
What Types of Forces Can Hold Objects
Together?
How Do
They Stick
Adhesion
Method
3
© 2009 McREL
What Sticks?
Station Materials
4
Beaker of
Water, Paper
Towel, Plastic
Transparency
5
Washers,
Velcro®,
Plastic
Transparency
6
Transparent
Tape and
Plastic
Transparency
7
Additional
Station
Which Objects
Stick Together?
What Types of Forces Can Hold Objects
Together?
How Do They
Stick
Adhesion
Method
4
© 2009 McREL
Variables
1. Choose one of the pair of objects that stuck
together during your exploration. Describe
factors (variables) that affect how well those
two objects stick together.
2. Describe an adhesive in your own words.
What are the properties that make it work?
3. Which factors or variables are testable and
which are not?
What Types of Forces Can Hold Objects
Together?
5
© 2009 McREL
Observations
4. Describe how you made observations in
today’s lesson.
a. What senses/tools did you use?
b. What observations were at the visible scale?
c. What dominant forces did you observe?
d. What are other forces that you observed that
may be at the invisible scale?
What Types of Forces Can Hold Objects
Together?
6
© 2009 McREL
Adhesion Methods
Method
Definition
Drawing
Example
Gecko Y/N
Why/ Why
Not?
Friction
Air
Pressure
Microinterlocking
Magnetic
Static
Electricity
Capillary
Wet
Adhesion
Electrical
What Types of Forces Can Hold Objects
Together?
7
© 2009 McREL
Making Connections
1. Describe one or two ideas that you learned
during this lesson.
2. How do things stick together?
3. Which of these methods can be eliminated as
an explanation for why the gecko can stick to
a ceiling?
4. What should we explore next?
What Types of Forces Can Hold Objects
Together?
8
© 2009 McREL
Flow Chart
1. How Can a Gecko
Walk on a Ceiling?
Scale: Visible
Dominant Force: Gravity
Tools: Eye
5. What Types of Forces
Can Hold Objects
Together?
Scale: Visible/Invisible
Dominant Force: Gravity
Tools: Eyes and Hands
2. What Do We Mean
When We Speak
About Surfaces in
Contact?
Scale: Visible
Force: Gravity
Tools: Eyes
6.
How MUCH Force Is
Needed to Make an
Object Stick? What
Factors Affect the
STRENGTH of Force
Acting?
What Types of Forces Can Hold Objects
Together?
3. What Are Your Ideas
About Small Sizes?
Scale: Visible/Invisible
Dominant Force: Varies
Tools: Eyes, Instruments
7. How Do We Measure
Forces at the Nano
Level?
4.
What Do We Learn
When We Look
More Closely?
Scale: Invisible
Dominant Force:
Extremely Small,
Large in Number
Tools: Special instruments
(scanning tunneling
microscope)
8. How Can a Gecko
Walk on a Ceiling?
9
© 2009 McREL