NGSS - Cross Cutting Concept: Form and Function
This lesson lays the foundation for next week's lesson, on seed dispersal. Through the act of discovery students identify the important parts of a seed.
By dissecting a seed students have an opportunity to see up close what is important about the seed. This builds on the NGSS cross cutting concepts of structure and function. Students investigate the structure of the seed and how this helps the function of producing viable offspring. This sets the stage for understanding the importance of seed dispersal for the continued survival of the plant.
Remember to soak the lima beans the evening before this lesson. I soak 2-3 lima beans per student. I chose a lima bean because it is easy for the students to open and to see the seed parts. I will have other types seeds soaking for students to open, to see if they can find the identified seed parts, after finishing the lab on the lima bean seed.
Question for the Day
Before I show the question of the day, I ask students if there is any new information we could add to our 'what we know about seeds' class log page. This helps connect today's lesson to our seed sorting lesson from last week.
I post a question for each science class to set the stage for the lesson. The 'question of the day' helps to direct the student's focus as we begin science.
I call the botanists to the rug to read the question and partner share their answers. I listen carefully to the students, paying attention to answers that I will use as a link to the next part of the lesson.
"Botanists, I heard some great discussions about what is inside a seed. I heard some of you say that there is a baby plant, this is called the embryo." I expose students to scientific terms as we learn the seed parts to help develop their academic vocabulary.
"Last week we observed how seeds are alike and different on the outside, through our sorting activity. Today we will look at what is on the inside of a seed." I show my lima bean diagram on chart paper with parts labeled: seed coat, leaves and root, and stored food.
I use this opportunity to develop the criteria for what should be on a diagram with the students. I ask students what they notice about my diagram that makes it different than just a picture. As students tell me what they see, I write their criteria on post-its and place it on the lima bean diagram.
"The purpose of a diagram is to share information to share information clearly and which is easily understood by anyone who should look a the diagram."
"Botanists, this is only a diagram, or model of what a botanist drew to show what is inside a lima bean. As scientists, we want to see if this information matches with what we observe in the real world. Scientists, will test information to see if they can verify the information as a fact. What could we do to find out if these are parts found inside a seed? Or if they are found in different types of seeds?"
By asking the question, I am prompting my students to think like a scientist, how can we test this? Sometimes they surprise me with their answers and give me another way to consider a problem. Fun.
If my prompt does not lead to a seed dissection I will bring it up as a suggestion.
"Botanists, today you will be opening a lima bean that has been soaking in water overnight to see if the parts of the seed that we saw on the diagram are in a real the lima bean."
Under the document camera I project a soaked lima bean.
"I am going to show you a short video that shows how to open the lima bean so that you can look for the seed parts. Pay close attention to see how to open the lima bean. Notice which side of the lima bean she splits apart. I will ask you which side to split open after you watch this short video."
I have cued the video on how to open a lima bean. This video can also be used to review the parts of a lima bean at a later time. You can turn the volume down so that you can use your terms versus what is on the video.
I have drawn a lima bean on the board and ask for a volunteer to show us where we split the seed.
"That's correct, we want to split the seed on the side where it curves out." I use the lima bean to under the document camera to point out where the students will split the seed.
You will carefully open the seed and look closely to see if you can find the parts of the lima bean that we talked about earlier. They are.... "(I wait for student responses).
I have attached a close up of a lima bean image that shows the embryo. I will use this image the next time I do this lesson. Some students had a hard time finding the embryo in their plant. For some it was because they opened the plant on the wrong side. For others, they weren't able to transfer the diagram to their seed, so labeling a lima bean photo on the smartboard would be a way to scaffold students' observations and help them label their actual lima bean.
I pass out the lima bean worksheet and read the directions. After directions and questions have been discussed. I pass out the lima beans, magnifying lenses, and paper plates. Students will dissect their lima bean on the paper plate and later tape the lima bean parts and label.
I walk around to check that students are using the magnifying lens correctly and asking them to show me the parts of the dissected bean. This helps to reinforce vocabulary and encourages them to look closely at their seed.
I noticed students would refer to the class diagram to help them identify seed parts in their dissected seed. So be sure to leave this in a prominent place in your room as the students work on this lesson.
After reviewing students' diagrams I saw that some students did not place the embryo on the correct side of the seed ('diagrams are accurate', one of our agreed upon criteria for our diagram). When doing this lesson again, I will ask, "What side is the embryo on?" to help students connect to our reason for opening the seed on a designated side and to reinforce accuracy in our drawing.
I give students a heads up when there is about 10 minutes left to work on the lab.
To be sure we have closure before transitioning to the next subject I plan to give myself and the students about 10 minutes to clean up and finalize their lab. So that we have about 5 - 10 minutes as a whole class to discuss the lab and lesson.
"Botanists, it is time to pick up our lab. I am going to pass out scotch tape so that you can tape your lima bean parts to your paper plate and label the parts. Then place your lima bean plate in your homework folder, so that you can show your family what you did in science today and teach them about the parts of the seed."Students taking work home to use as a discussion starter helps integrate home and school. Learning is reinforced and celebrated.
The following day I asked students to raise their hand if they showed their labeled lima bean to their family. I had about 80% participation. Next time, I will incorporate taking the lab home and sharing it with a family member into the homework to encourage the connection between home and school with all students.
Central to the Wrap-up Time
I ask students to turn in their diagrams. Then I signal students to take a seat on the rug.
I point to the class seed diagram. "Today you looked at a baby lima bean plant, what would happen of the lima bean plant did not make any seeds? Or if none of the seeds were planted? The lima bean put a lot of energy into making this seed and to make sure the seed would have everything it needed to survive, such as food and a covering. The only thing the seed needs now is a safe place to grow. In the next lesson we will look at a some seed designs to help make sure the seeds have a place to grow."
I ask if this lab made them think about any other questions that have about seeds. I note their questions on the unit class log book we started last lesson. Then we will look back over the chart to see what else we may want to add or if there is information we want to change.
Last I read the short, lively story, The Watermelson Seed, and ask the students could a watermelon grow in our stomach? Is there anything we know about seeds that may help us make an hypothesis? I do not weigh in with my view, but provide a venue for the botanists to discuss. Prompting them to back up their hypothesis about what they know about seeds.
Other possible discussion questions: How could we find out if the seed did soak up water? How does water help a seed grow into a plant?
Later when I review the student's diagrams, I will use the diagram criteria that students established to student work.