This lesson teaches students about the polarity of magnets and the how the terms 'attract' and 'repel' are used to describe the motions of the magnets as they come into close contact. It is important for first graders to have some understanding of how magnets work so that they do not just think they are magic! So, in this lesson students will watch a 12-minute video that shows lots of examples and clearly explains polarity and then I will demonstrate polarity using some of the same magnets that the students used during their investigation.
*Magnets for demonstration
To begin this lesson, I start by showing the KWL chart that we started during the introductory lesson. I say,
"We are going to focus on this question today: 'How do magnets work?' To learn about the science that makes magnets work, we are going to first watch a video and then I am going to show you with our own magnets. First, we are going to draw a labeled diagram so you will understand what you see. Ready?"
I start an anchor chart titled 'Magnets' and draw a Bar magnet and I label "North" and "South". Then I say,
"We have learned how some forces, like pushes and pulls, have to have direct contact. In other words, you have to touch something to push it. With a magnet, that is not always true. There are forces called 'unseen' forces - you do not see them. In this video, you will hear how magnets have a 'magnetic field' around them. It isn't like a field with flowers and grass. It means an invisible area that creates the force. We will talk more about it after the video."
This is a really complex topic for first graders, but I feel it is necessary for them to have at least a basic understanding that there is a north and south pole and a magnetic field that is creating an unseen force. I will explain it more after the video through the demonstration.
For the activity section of the lesson today, I show this video. It has lots of demonstrations of magnet use and also clearly explains the polarity of magnets. The video is about 12 minutes long. Making observations from media about relationships (magnetism and force) in the natural world supports Science and Engineering Practice 4.
After the video, I say,
"Now, you heard two really important words in the video that we need to talk about and write in our journals. The first is 'attract'. That means that the magnets were pulling towards each other. The second word was 'repel' which means that they were pushing away from each other. You add those to your journal and I will add them to our chart."
I find that requiring students to keep notes in their journal helps them to stay focused on the task and also gives them a place to return to look at the information later. Recording information including observations, thoughts and ideas, and then sharing them, supports Science and Engineering Practice 4.
Then I move on to the demonstration. I use the same magnets that the students used in the introductory lesson on purpose - I do not want them to think that I changed anything on them.
For the demonstration, I lay one bar magnet down on the table and I show how I can use the same pole to repel the magnet. Then, I use the opposite pole to attract the magnet. I say,
"The poles that are the same - like North and North - repel which means they push each other away. The poles that are opposites - North and South - attract, which means they do what? That's right - they attract and pull together. They are unseen forces - they don't actually touch to move each other!"
After the demonstration, we move into the wrap up.
To wrap up the lesson and make sure my students understand this very complex topic I ask,
"How can we write down our findings from today?"
As we discuss what we have figured out about opposites attracting and same poles repelling, I make sure that students are using the vocabulary correctly. Then, I say,
"Turn to your neighbor and answer the question 'How do magnets work?'!"
Communicating ideas and information supports Science and Engineering Practice 8. Then I invite a few students to share their responses as we end for the day.