Exploring States of Matter - Gases
Initial Publication Date: September 9, 2009
Summary
In this series of chemistry labs, students will learn the three states of matter: solid, liquid, and gas. How molecules contract or expand as they change state will be modeled. In this series of lessons students will observe the behavior of gases through hands on experiments. Students will have the opportunity to keep lab notes about their observations and questions.
CollapseLearning Goals
This activity is designed for students to strengthen their understanding of the properties of gases. Students will be able to describe a phenomenon that shows evidence of gases.
Context for Use
This activity minimally takes four class periods. It is designed for 4th graders. The first lesson is lecture, demonstration, and role playing. The next three will be guided discovery experiments. Student led experiments generated by questioning/questions during lessons would require more time.
Description and Teaching Materials
Activity Description
Materials: approximately 30 marbles, overhead projector, clear cup or Petri dish
Day 1
Explanation of solids, liquids, gases.
Start with reviewing states of matter. Explain that matter is made up of atoms which often combine to make molecules. Whether matter is a solid, liquid, or gas depends upon how fast the molecules are moving and how far apart the molecules are. Changing how fast the molecules move around changes the state of matter. Heat will change how fast the molecules move around. Pack marbles into the Petri dish and explain that we'll pretend the marbles are molecules of water as a solid. We call this ice. The molecules can't move - they're packed together and will hold their shape. Next, pretend to apply heat to the molecules (take out some marbles). In liquid state, molecules can move past each other. Jiggle the dish with marbles so they roll past each other. The ice would melt and we'd have liquid water. Next, if you apply a lot of heat, the molecules get really excited and start moving around a lot. Jiggle the dish wildly and marbles will fly out (be careful). When something is a gas, the molecules move out and away from each other. They will keep moving out until something stops them. For instance, steam in a bathroom stops at the walls, on the mirror, etc. If you open the door, the steam escapes.
At this point you could ask which students would like to pretend to be molecules as a solid, liquid, and gas. Students would pack tightly together as solid, move around a bit as a liquid, and spread out to all corners of the room as a gas.
Students will draw and label today's lesson in their science notebook. Ask them to share and compare their drawing with a neighbor.
Day 2
Materials: yard stick, two balloons, string, balance scale, straight pin
We can see that gas has weight.
Start the lesson by reviewing what a gas is. Ask for examples of gases that they are familiar with. Note: Be sure to explain the difference between liquid gasoline and the state of matter gas.
Show the students two balloons of the same size. Ask: What's inside? How did it get there? Why doesn't a balloon just inflate by itself? Lead them to the conclusion that there must be the same amount of air forced inside (because the balloons are the same size).
Next, attach each balloon to the end of a yard stick and find the balance point. Remind them that if the balloons are balanced they must be equal in weight. Tell them a student will pop one balloon. Ask them to predict what will happen. (When one balloon is popped, that end of the stick will go up and the full balloon will go down because the air (gas) has escaped the balloon.) Guide students to the understanding that the popped balloon lost some of its weight. Ask students if they can think of any other way to prove air has weight. (one suggestion would be to blow up a balloon fully and one half way, then use the same middle balance point - or use a balance scale).
Students will draw and label today's experiment in their science journals.
Day 3
Materials: 2 balloons, 2 bottles, access to freezer
Heat affects gas molecules.
In this experiment you will have stretched two balloons of the same size over two bottles of the same size. These will be put in the freezer for an hour before class.
Set the two bottles in front of the class and ask what they think is in the bottles. Of course, air, which is a gas is inside. Let the bottles warm up or have students warm the bottles with their hands, or you could shine lights on the bottles. As they warm up the balloons will inflate because the air molecules move faster when warmer. As the balloons expand, ask the students to guess why that is happening. Someone may ask if the balloons will shrink if they go back in the freezer. Try it!
For this journal writing, I would guide them in showing air molecules taking up less space when cold and bouncing around faster when warm.
Day 4
Materials: perfume or other odoriferous product
We smell gas.
Begin lesson by asking how we smell things. Of course our nose is part of it. We have smell receptors in our nose that send messages to our brain. When a molecule of something hits the receptors - we smell something. So actually a very tiny piece - in the form of gas - of the object we're smelling is in our nose. (could be a big YUCK!)
To get an idea of how smell travels open a bottle of perfume at one end of the classroom. Have the students raise their hands when they smell it. Not everyone will smell at the same time. Discuss how the scent travels and how ventilation may be affecting the path of the perfume molecules. You could also time if warm or cold perfume is smelled faster.
Ask students to draw the path of the perfume molecules as they travel through the room.
Materials: approximately 30 marbles, overhead projector, clear cup or Petri dish
Day 1
Explanation of solids, liquids, gases.
Start with reviewing states of matter. Explain that matter is made up of atoms which often combine to make molecules. Whether matter is a solid, liquid, or gas depends upon how fast the molecules are moving and how far apart the molecules are. Changing how fast the molecules move around changes the state of matter. Heat will change how fast the molecules move around. Pack marbles into the Petri dish and explain that we'll pretend the marbles are molecules of water as a solid. We call this ice. The molecules can't move - they're packed together and will hold their shape. Next, pretend to apply heat to the molecules (take out some marbles). In liquid state, molecules can move past each other. Jiggle the dish with marbles so they roll past each other. The ice would melt and we'd have liquid water. Next, if you apply a lot of heat, the molecules get really excited and start moving around a lot. Jiggle the dish wildly and marbles will fly out (be careful). When something is a gas, the molecules move out and away from each other. They will keep moving out until something stops them. For instance, steam in a bathroom stops at the walls, on the mirror, etc. If you open the door, the steam escapes.
At this point you could ask which students would like to pretend to be molecules as a solid, liquid, and gas. Students would pack tightly together as solid, move around a bit as a liquid, and spread out to all corners of the room as a gas.
Students will draw and label today's lesson in their science notebook. Ask them to share and compare their drawing with a neighbor.
Day 2
Materials: yard stick, two balloons, string, balance scale, straight pin
We can see that gas has weight.
Start the lesson by reviewing what a gas is. Ask for examples of gases that they are familiar with. Note: Be sure to explain the difference between liquid gasoline and the state of matter gas.
Show the students two balloons of the same size. Ask: What's inside? How did it get there? Why doesn't a balloon just inflate by itself? Lead them to the conclusion that there must be the same amount of air forced inside (because the balloons are the same size).
Next, attach each balloon to the end of a yard stick and find the balance point. Remind them that if the balloons are balanced they must be equal in weight. Tell them a student will pop one balloon. Ask them to predict what will happen. (When one balloon is popped, that end of the stick will go up and the full balloon will go down because the air (gas) has escaped the balloon.) Guide students to the understanding that the popped balloon lost some of its weight. Ask students if they can think of any other way to prove air has weight. (one suggestion would be to blow up a balloon fully and one half way, then use the same middle balance point - or use a balance scale).
Students will draw and label today's experiment in their science journals.
Day 3
Materials: 2 balloons, 2 bottles, access to freezer
Heat affects gas molecules.
In this experiment you will have stretched two balloons of the same size over two bottles of the same size. These will be put in the freezer for an hour before class.
Set the two bottles in front of the class and ask what they think is in the bottles. Of course, air, which is a gas is inside. Let the bottles warm up or have students warm the bottles with their hands, or you could shine lights on the bottles. As they warm up the balloons will inflate because the air molecules move faster when warmer. As the balloons expand, ask the students to guess why that is happening. Someone may ask if the balloons will shrink if they go back in the freezer. Try it!
For this journal writing, I would guide them in showing air molecules taking up less space when cold and bouncing around faster when warm.
Day 4
Materials: perfume or other odoriferous product
We smell gas.
Begin lesson by asking how we smell things. Of course our nose is part of it. We have smell receptors in our nose that send messages to our brain. When a molecule of something hits the receptors - we smell something. So actually a very tiny piece - in the form of gas - of the object we're smelling is in our nose. (could be a big YUCK!)
To get an idea of how smell travels open a bottle of perfume at one end of the classroom. Have the students raise their hands when they smell it. Not everyone will smell at the same time. Discuss how the scent travels and how ventilation may be affecting the path of the perfume molecules. You could also time if warm or cold perfume is smelled faster.
Ask students to draw the path of the perfume molecules as they travel through the room.
Teaching Notes and Tips
As I mentioned before, be sure to tell students that there is a difference between car gas and the state of matter gas. I have taught these lessons in the past, but now I have added more inquiry or exploratory options to the activities. We have just started to use science journals and I feel documenting these experiments like real scientists will help them review concepts they've learned.
Assessment
Assessment will be ongoing during instruction and questioning. Also, student science journals will be reviewed for completeness.
Standards
Standards
Physical Science: A. Structure of Matter
The student will know that heating and cooling may cause changes to the properties of a substance.
History and Nature of Science: B. Scientific Inquiry
The student will participate in a controlled scientific experiment.
Physical Science: A. Structure of Matter
The student will know that heating and cooling may cause changes to the properties of a substance.
History and Nature of Science: B. Scientific Inquiry
The student will participate in a controlled scientific experiment.