Prove It!
Title: "Prove It " -- Which Direction Does Hot and Cold Air Go?
Subject: Science
Grade Level: 1st/2nd -- April
Teacher of Lesson: Gina Chung
Approximate Time: 45 minutes
Background Information
To introduce the concept of how hot air rises and cold air sinks, the students will be read to from an investigative science book. Motivate the students by letting them know it can be proven and that they can even visually see it. This activity will also be modeled by the teacher as the whole class observes. As the students are becoming more familiar with making observations, they can write down their descriptions of what they see, as it is being done. As it will be difficult to do the experiment repeatedly in the classroom, children should be encouraged to watch extra carefully. If they need more time to observe, the activity may be extended over a period of days for the students to look at all the movements of the water. Again, the students will be investigating the beginning concepts of air pressure.
Objectives
- Students will summarize what they know about the concept of hot air rising and cold air falling from the investigative science book.
- Students will further understand the concept by observing an experiment and proving it through a visual experience.
- Students will predict what happens when they reverse the experiment.
Materials
- investigative science book -- Flash, Crash, Rumble, and Roll, by Franklyn M. Branley
- large see-through tub
- hot and cold water
- small bottle
- food coloring
- science observations worksheet/journal
Procedures
Anticipatory Set: Earlier in the day, read the story to the whole class, discussing some of the concepts they learn. Discuss what air pressure might be. Have students think of different types of pressure. Show a balloon without air in it, then blow it up. Press on it to show pressure. Discuss some other analogies of pressure and real-life situations of hot air rising, cold air sinking. [hot air balloons, hotter on the top bed of a bunk bed, toes get colder than their heads...]
- Before they begin to observe, they should answer the first question of what they understand about the concept already. (Explain in your own words what happens on page 9 and 10 of Flash, Crash, Rumble, and Roll. Do you know this to be true? PROVE IT!!)
- Work at a table where all the students can observe. Fill the clear tub halfway with warm water. Fill the small bottle with cold water and then add a few drops of food coloring.
- Have one of the students place a thumb over the mouth of the bottle and hold it sideways, lower it into the warm water, and then release the thumb. The teacher may also have to do this step or assist the volunteer. (What happens when the cold water leaves the bottle? Why do you think this happened? How does this prove what we read in the story?) Each child should record their observation.
- The students will reverse the experiment by filling the bowl with cold water and the bottle with warm water colored by food dye. Before they do, each student will write down their prediction of what the results will be. (If you switch the warm and cold water, what do you think will happen? What happens? How is this different or the same to what you first thought?)
Evaluation of Student Learning
- Review the answer to the first question on their observation sheet. Were they able to summarize the concept in their own words? Did they seem to understand the concept to begin with?
- Review the continuing answers on their observation sheet, as well as listen to their thinking processes as they observe the experiment. Did their results further their understanding of the original concept? Were they satisfied that the concept of hot/cold air by using hot/cold water was proven?
- Review their prediction. Is it consistent with what they observed through the hands-on experiment? Did they make the connection of warm water rising and cold water sinking?
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