In order to find out about the ideas that students have about gases, I interviewed 3 students about their ideas of gases and their properties.  The questions will be asked such that they allow students to express their ideas about the misconceptions below.  The questions that I asked concerning these misconceptions are in italics.  The students' responses are in noted as student 1, student 2, student 3.  I found these misconceptions on the following web page: http://www.amasci.com/miscon/opphys.html, which is titled Science Hobbyist Misconceptions.  In addition, I also found similar misconceptions such as numbers  4 and 6 in the Making Sense of Secondary Science:  Research Into Children's Ideas book.

Students' Misconceptions about Gases

Interview and Responses

1.  Heating air only makes it hotter.
What happens when air is heated?

Student 1:  It moves around a lot and it expands.
Student 2:  It expands.
Student 3:  Expands.
 

2.  When a gas expands the particles get larger.
Expansion of matter is due to expansion of particles rather than to increased particle spacing.
Why do gas particles expand?

Student 1:  Because they are too small to fit into a confined area and they expand to fit into bigger areas whenever they can.
Student 2:  Because they attract heat.
Student 3:  Because they do.

How does the spacing of particles change when they expand?

Student 1:  They space farther and father apart as they expand.
Student 2:  I don't know.
Student 3:  Wider space between each particle.
 

What do the gas molecules look like before they are heated and after they are heated?

Student 1:  Before they are heated, they move around a little bit and they are not very compressed.  When they are heated, they move around and expand more.
Student 2:  They are small at first and then they increase in size as they are heated.
Student 3:  The gas molecules are small and then they get large.
 

From the information that I obtained from these responses, I concluded that most students know that a gas expands when it is heated.  Yet, it is clear from the responses that most of the students believed that the molecules increased in size when they were heated.  In fact, this is not true and is discussed in the the temperature node.  In addition, it is discussed in the lesson concerning temperature.

3.  There cannot be any pressure around us, since we cannot feel it.
Does air exert pressure?  Why?

Student 1:  Yes, because air can be compressed into a contained area and it changes pressure, if there is too much air in the container it will explode because there is too much pressure.
Student 2:  No, it just doesn't.
Student 3:  Yes, but I'm not sure why.
 

From the responses to this question, it is apparent that not all students feel that there is air pressure.  As a result, I have developed lessons, that involves students looking at these following phenomena, How does the egg in the Egg In the Bottle Demonstration?, and The Crushing Can Demonstration-Why does the can collapse?  to realize that air does exert pressure!

4.  Gases do not have mass.
Do gases have mass?  If so, how much?

Student 1:  Yes, the total mass of all the particles of the gas put together.
Student 2:  Yes, but you would have to count the number of gas particles to know how much.  (How would you count them).  I'm not sure.
Student 3:  Yes, I do not know.

This misconception is discussed in the moles page.
5.  Air and oxygen are the same gas.
What is air?

Student 1:  Many molecules of the oxygen gas in our atmosphere.
Student 2:  Air is something that you cannot see.
Student 3:  What we breathe.

What is oxygen?

Student 1:  A gas that has an atomic mass of 16.00g.
Student 2:  The air that we use to breathe.
Student 3:  Again why you breathe.

How are air and oxygen different?

Student 1:  Air is two particles of oxygen and not one.
Student 2:  I'm not sure.
Student 3:  Air contains different elements, oxygen is an element.

After I reviewed this misconception and the responses, I concluded that students may not be sure why air is different from oxygen.  As a result, I have addressed this in the gases page so that students will not confuse air with oxygen.

6.  Helium and hot air are the same gas.
What is helium?

Student 1:  A gas that is much lighter than air and oxygen.
Student 2:  Air in balloons that float.
Student 3:  A gas that makes your voice squeak when you inhale it.

Is helium hot air?
Student 1:  Yes.
Student 2:  No.
Student 3:  No.

Although this can be a common misconception, students should realize that hot air is not helium.  As a result, this misconception will be addressed in the focus lesson and in the How do hot air balloons work? phenomena page.  From a discussion that I had a with the students, it seems that they may confuse helium with hot air because they know that it rises when placed in a balloon.  They seemed to confuse low densitygases with gas particles that are expanding.  As a result, this idea should be discussed in the because when students discuss in the How do hot air balloons work? page.

Reflection of Literature

After looking at these responses, I realized that students have a lot of the same conceptions as the general student population.  Although it is interesting to know what misconceptions students may have before teaching lesson, it takes a lot of good teaching to change these misconceptions into more accurate conceptions.  According to Diver, "Children develop ideas about natural phenomena before they are taught science in school" (DIver, 1).  As a result, I think that although students have constructed some knowledge about gases, it is easier to teach about science if we use daily phenomena.  As a result, I have chosen to include 5 different types of phenomena that concern gases in my series of lessons page.
 

In addition to interviewing students, I researched the following articles to learn more about what students think about gases and their properties.

In this article, the authors states that in order for students to learn about gases and gas laws, teachers need to teach about the properties of gases by teaching students such that they gain conceptual understanding (Huann-shang et.al).  As a result, my series of lessons are structured so that students learn about gases through a conceptual understanding before they learn about gases through the algorithmic approach by using the ideal gas law.  Although I tried to refrain from incorporating a lot of math concepts in this unit plan, the reality is that at the high school level, students should know how do solve gas problems by using the gas laws and their conceptual understanding of gases.

As I was constructing this project, I consulted my cooperative teacher about what misconceptions students had about gases.  In response, she stated that although it is important for students to have a conceptual understanding about gases, she also stated that it is important that students know what the variables mean and how all the gas laws such as Gay Lussac's Law, Charles' Law, Avogadro's Law, and Boyle's Law can all be derived from ideal gas law.  As a result, the ideal gas law page involves the introduction of variables and how Boyle's Law can be derived from the ideal gas law.

I found this article to be one of the most helpful when I was constructing the The Crushing Can Demonstration-Why does the can collapse?, phenomena page.  According to this article, many students try to explain this phenomena by relying on the gas laws instead of using their conceptual understanding of how gases behave.  As a result, students fail to realize that there two main points that needed to be discussed to explain why this phenomena works.  As result of this information, I have constructed this phenomena page such that it allows students to apply their observations to the properties of gases which will help them to understand why this demonstration works.

In this article, the inaccurate explanation of the Egg in the Bottle is discussed.  As a result, I referred to this article and made sure that I had the correct explanation as to why the Egg in the Bottle Demonstration works.

The Assessment of Students and Teachers' Understanding of Gas Laws
Huann-shyang Lin, Hsiu-ju Cheng, and Frances Lawrenz
Department of Chemistry, National Kaohsiung Normal University, 116 Ho-ping 1st Road, Kaohsiung, Taiwan
 

Using a Computer Animation to Improve Students' Conceptual Understanding of a Can-Crushing Demonstration
Michael J. Sanger, Amy J. Phelps, and Jason Fienhold
Department of Chemistry, University of Northern Iowa, Cedar Falls, IA

The Egg in the Bottle Revisited:Air Pressure and Amontons' Law
Louis H. Adcock
Department of Chemistry, University of North Carolina at Wilmington, Wilmington NC

Driver, R. et al.  Making Sense of Secondary Science:  Research Into Children's Idea.  New York:  Routledge.