ALEX Lesson Plan


Observing the Invisible

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  This lesson provided by:  
Author:Kathy Perkins
System: Tuscaloosa City
School: Tuscaloosa City Board Of Education
The event this resource created for:ASTA
  General Lesson Information  
Lesson Plan ID: 34783


Observing the Invisible


Matter is made of particles too small to be seen.  But if we can’t see these particles, how do we know they exist?  In this lesson, students will plan and carry out investigations with air and simple solutions to provide evidence that all types of matter are made of tiny particles that are invisible to the human eye.

This lesson results from a collaboration between the Alabama State Department of Education and ASTA.

 Associated Standards and Objectives 
Content Standard(s):
SC2015 (2015)
Grade: 5
1 ) Plan and carry out investigations (e.g., adding air to expand a basketball, compressing air in a syringe, dissolving sugar in water, evaporating salt water) to provide evidence that matter is made of particles too small to be seen.

NAEP Framework
NAEP Statement::
P4.3: Matter exists in several different states; the most common states are solid, liquid, and gas. Each state of matter has unique properties. For instance, gases are easily compressed while solids and liquids are not. The shape of a solid is independent of its container; liquids and gases take the shape of their containers.

NAEP Statement::
P4.4: Some objects are composed of a single substance; others are composed of more than one substance.

NAEP Statement::
P8.1: Properties of solids, liquids, and gases are explained by a model of matter that is composed of tiny particles in motion.

Unpacked Content
Scientific And Engineering Practices:
Planning and Carrying out Investigations
Crosscutting Concepts: Scale, Proportion, and Quantity
Disciplinary Core Idea: Matter and Its Interactions
Evidence Of Student Attainment:
  • Provide evidence based on investigation results that matter is made of particles too small to be seen.
Teacher Vocabulary:
  • Investigation
  • Variable
  • Data
  • Hypothesis
  • Conclusion
  • Matter
  • Describe
  • Observe
  • Evidence
  • Immensely
  • Bulk matter
  • Particle
Students know:
  • Matter is made of particles too small to be seen Matter too small to be seen still exists and may be detected by other means.
  • Gasses are made of matter particles that are too small to see, and are moving freely around in space (this can explain many observations, including the inflation and the shape of the balloon, and the effects of air on larger particles or objects).
  • The behavior of a collection of many tiny particles of matter and observable phenomena involving bulk matter (e.g., an expanding balloon, evaporating liquids, substances that dissolve in a solvent, effects of wind).
  • There is a relationship between bulk matter and tiny particles that cannot be seen.
Students are able to:
  • Identify the phenomenon under investigation.
  • Identify evidence that addresses the purpose of the investigation.
  • Collaboratively plan the investigation.
  • Collect and analyze the data.
Students understand that:
  • Natural objects exist from the very small to the immensely large.
AMSTI Resources:
AMSTI Module:
Matter and Interactions

Alabama Alternate Achievement Standards
AAS Standard:
SCI.AAS.5.1- Recognize that matter is made of particles too small to be seen.

Local/National Standards:


Primary Learning Objective(s):

The students will investigate different materials to observe their properties and construct an argument from evidence that matter is made of particles too small to be seen.

Additional Learning Objective(s):

The students will:

  • plan and document investigations.
  • write an explanation using evidence to support a claim.
 Preparation Information 

Total Duration:

61 to 90 Minutes

Materials and Resources:

  • Can of aerosol air freshener
  • Dr. Art’s Guide to Science, by Art Sussman; ISBN 0‐7879‐8326‐8
  • Square sticky notes in two colors
  • Chart paper or marker board
  • Marker
  • Ice
  • Electric skillet
  • Balloons
  • Drinking straws
  • Tape
  • Paper
  • Cardboard
  • Empty water bottles
  • Plastic bags (any type - Ziploc, grocery, newspaper, produce, etc.)

Materials for each group of four students (used in Explore portion of lesson):

  • 200+ ml graduated cylinder or clear plastic 2-cup measuring cup
  • 1 cup or 100 ml warm water
  • ¼ cup or 25 ml sugar
  • Spoon
  • 3 – 4 Small solid objects such as marbles, dice, or crayons

Technology Resources Needed:

Computer with Internet access connected to a projector for showing videos


Teachers should understand basic principles about particle movement in various states of matter.  Dr. Art’s Guide to Science (p. 52-57) provides an excellent explanation.  Additional information can also be found at Chem.Purdue.Edu.


Engage (5 – 10 minutes):

Stand at the front of the classroom and spray air freshener into the air.  Have students describe what they see to a partner. (The droplets go into the air, begin falling, and then disappear.  Some students may say that the air freshener falls to the floor.  Rather than challenging this idea, continue with the demonstration so students can figure out what happens for themselves.) 

Ask students to raise their hands when they smell the air freshener.  (Students at the front of the classroom will smell it first, and then others will begin to sense it as the air freshener diffuses throughout the room.)  Have partners discuss why they think everyone did not smell the air freshener at the same time and how they were able to smell it at all since you did not spray it directly on them.  How did the air freshener reach the back of the room without being seen?

Shake the can of air freshener and ask “Is the air freshener a liquid or a gas?”  What causes the liquid to change form?  Is it still the same substance when it changes from a liquid to a gas?  How do you know? 

Tell students they will explore different types of matter to find evidence that it is there, even if they cannot see it, because it is made of particles too small to be seen.  Then students will prove that matter is made of particles too small to be seen using evidence from their investigations.

Explore (10 - 15 minutes):

Divide students into groups of four and distribute materials to each group.  Have each group measure 1 cup warm water in a 2-cup measuring cup (or 100 ml warm water in a graduated cylinder).  Drop the solid objects in the water and observe what happens (the water level rises).  Ask students why this happens (the objects displace the water).  Remove the objects from the water, making sure that no water is spilled or refilling the cup/graduated cylinder to the previous level.

Tell students that they will now mix ¼ cup sugar into the cup of water.  Have them predict what will happen to the water level.  Distribute one color of sticky notes.  Have students write their names on the notes and use them to make a class prediction graph on chart paper (see sample graph in attachment section).  Students will predict whether they think the water level will decrease, stay the same, increase slightly, or increase by ¼ cup.  Have students discuss the reasoning behind their predictions.

Have students dissolve ¼ cup sugar into the cup of water and observe what happens to the water level.  Give students a second color of sticky note for them to write their names on and post on the class graph showing what they observed.  Have students discuss the following questions in their small groups:

  • Why didn’t the water level rise by ¼ cup when we added ¼ cup sugar?
  • Where did the sugar go?  How is that possible?

Explain (15 -20 minutes):

View and discuss slideshow about particles.

Read the explanation of particles on pages 52‐57 in Dr. Art’s Guide to ScienceIn this explanation, the author compares the particles of solids, liquids, and gasses to dance partners at a party.  The same number of dancers (particles) are present at each point, but the size of the dance floor (phase of matter) determines how much the dancers can move and what types of bonds they form.  As you read this explanation, demonstrate the three phases of matter by doing a demonstration with ice.

Show students an ice cube and ask what it is made out of (water).  Put the ice cube in an electric skillet and begin heating it.  Allow it to melt as you read the portion of Dr. Art’s story about liquids.  Tell students to observe how the water spreads out once it has melted.  Continue reading about gasses as the water begins to boil and change to water vapor.  Students will observe steam rising, but then the water seems to disappear.  Where has the water gone?  How can we prove that the water is still in the air? (Hold your hand or the lid of the skillet over the water and feel or see the vapor condense back into water.)  Remind students that even though the water particles may spread out so much that they are no longer visible, they are still present.

Elaborate (25 - 30 minutes):

Students will use air to complete an engineering design challenge to prove that matter is made of particles too small to be seen.  

Show students Zoom 1.5-minute video from PBS.   In this video, children use air to lift a heavy table.  Discuss how this proves that matter is made of particles too small to be seen.  (Even though we cannot see air in the plastic bags, it must be there to be able to lift the table.)

Tell students they will plan and conduct investigations that also prove the existence of tiny invisible particles.  Provide access to the following materials: balloons, straws, tape, paper, cardboard, empty water bottles, and plastic bags.  Students may work individually or in pairs to create something with the materials that shows the existence of air.  Their investigations may be as simple as releasing an inflated balloon to see it zip across the room as air is released, or as complex as a cardboard car powered by air.  Have students use the planning guide from the attachments section (“Proving Matter is Made of Tiny Particles Using the Engineering Design Process”) to plan, implement, and explain their investigations. Students must construct a device consisting of at least two parts that can be used to demonstrate the existence of particles too small to be seen, present their devices to the class, and explain how this device proves these invisible particles exist.

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Assessment Strategies

Observe students throughout the lesson and evaluate their explanations of their investigations using this rubric.

Have students present their devices to the class, explaining how they constructed their devices.  Then have students demonstrate what the device does and explain how the device proves the existence of particles too small to be seen.  Students should also share any modifications they made to their plan to improve the device using the engineering design process and discuss what they learned throughout this process.


  • Give students two syringes and tubing to attach the syringes.  (A Hydraulics Kit containing these materials can be purchased from Hobby Lobby, or this STEM kit is available for free to Civil Air Patrol Educator Members.)  Have students use the syringes to compress air, and then repeat the investigation with water to show the differences in particle density between gasses and liquids.
  • Make air cannons or stomp rockets to show how moving air can move objects.   Click here for  Design Squad directions to make an air cannon that shoots pom-poms. 


  • Group students needing assistance with peer tutors, and have them complete the engineering challenge with a partner.
  • Preview or review content with this 3:49 minute “Crash Course” video about particles.
  • Perform additional investigations from this resource guide.
  • Add additional prompts to the planning guide before printing (lines for writing or suggestions for structures that could be made with the supplied materials) or complete the planning guide together in a small group.

View the Special Education resources for instructional guidance in providing modifications and adaptations for students with significant cognitive disabilities who qualify for the Alabama Alternate Assessment.