In this blog post I share my best lesson planning tips to facilitate this lesson. I hope it gives you some ideas and saves you some time! The purpose of this project is to model DNA structure and the base pair rule.
Also check out my blog post DNA Model Keychains: An Engaging Hands-on Lesson and Fun Activity Before Holiday Break! to read more about what students learn in this lesson, why I love teaching it, the challenges, cost, and to explore other aspects of this lesson!
Lesson Planning Tips
- Buy the materials in advance
- Prep the beads in stations
- Make a few of the keychains yourself before the lesson to practice
- Split the lesson into 2 days
- Day 1- Make a Key and Gather materials
- Day 2 – Cut the wire. Demonstrate the first few steps, and have students copy you
- Draw diagrams on the board
- Conclusion paragraph
- Stamp DNA keychain paper for completion
- Summary of my best tips for success!
Buy the Materials in Advance
Buying materials in the right amounts is maybe the most challenging part of this activity for me. Estimating is a skill, and you will definitely put it to use here!
Each year I either have to make extra trips to the store to buy more supplies, or return unused beads because I purchased too many. If you do this activity year after year, you can reuse the extra beads from previous years, and that helps a lot with having the right amount.
The exact number of beads in each container is not specified, so there is some trial and error involved.
Here are some of my estimates for 1 class of around 35 students:
- 1 full spool of 28G wire, silver or gold colored
- 2 containers of gold round beads (called Czech seed beads at the craft store)
- 2 containers of silver round beads
- 1 container of yellow tube beads (called bugle beads at the craft store)
- 1 container of green tube beads
- 1 container of red tube beads
- 1 container of blue tube beads
- 2 packs of keyrings (18 rings each)
- 1 class set of Petri dishes, plus 6 more to divide the beads
- Masking tape
- Sharpies
- 1 class set DNA Keychain paper
- Optional: a class set of printed directions, or 1 packet of directions per table
Prep the Beads in Stations
Students collect the materials for their keychains by visiting stations around the room. Each station has a label with the color and number of beads they need.
Each student needs to collect:
- 18 round gold beads
- 18 round silver beads
- 4 blue tube beads
- 4 green tube beads
- 5 red tube beads
- 5 yellow tube beads
Make a Few of the Keychains Yourself Before the Lesson to Practice
This is one of my most important tips for this lesson! In each class there are 35 students doing 35 different things. The more familiar I am with what challenges they will face and how to problem solve, the better day we’re going to have.
I made 2 or 3 DNA model keychains to practice before teaching this lesson. It helped me become familiar with the process and all of the little things that can go wrong or make it more difficult to finish.
The first few steps are the trickiest. After that the steps are are repeated and the model is pretty easy to make.
The other tricky part is making a little loop at the end for the keyring. Most of my students wanted me to do this very last step for them, and I only got better with practice.
Split the Lesson Into 2 Days
This activity works best when split into 2 block periods. I find it best to figure out all of the materials on Day 1, and then on Day 2 start the keychains all together as a class.
Figuring out all of the materials on Day 1 allows us to start the second day in a calm and fresh state.
A full block period dedicated to putting the models together on Day 2 is important and works best for me. Some students will need an entire block period to assemble their keychain. Some may need even more time to complete their model and take them home.
Day 1 – Gather Materials and Make a Key
On the first block day, students get a DNA Keychain handout and we talk about the project. They gather materials to construct the keychains, and make a key.
Each student gets a petri dish to collect their beads. They visit stations around the room, count the number of beads, and put the beads in their petri dish. You can use envelopes, little baggies, or whatever you have to hold the beads. But the Petri dishes keep the beads from rolling off the table while they’re working so they work great.
When students finish, they secure the petri dish with masking tape and write their name and period number on it. Students put their petri dish in a designated spot by period number before they leave.
Next we create a key on their DNA Keychain handout. We do it together and everyone has the same color scheme and key. Students can make their own key and pick different colors for the 4 nucleotide bases. But if students choose their own colors for the bases, it’s harder for me to catch if they are matching the base pairs correctly. It’s a lot easier to check their work if we all use the same key, and we can avoid them having to undo their work and restring the beads. The wire only gets more difficult to work with as we go. Undoing stitches and restringing beads only makes it more of a challenge.
This all takes 30-45 minutes, so we do something else to fill the rest of the period. Even if there’s still time in the period to get started on the keychains, it’s worth waiting for the next full block period to start. That way most students will finish in the time provided next class.
Day 2 – Cut the Wire. Demonstrate the First Few Steps and Have Students Copy You
On Day 2 we construct the keychains. I love how we already went over everything the previous class period. Students take out their DNA Keychain handout, grab their petri dish with beads in it, and bring it back to their desk. A copy of directions for each student to make the jewelry was set out at each table before they arrived.
Cut the Wire
I go around to each students’ desk to cut the wire. They need about an arm’s length, from the fingertips to the shoulder. It’s longer than they need, which is good. When putting the beads on, it gets bent and harder to work with. Sometimes you need to trim the ends, so the extra length helps.
When students get the wire, they should straighten it out gently using their nail. Make it even in half, then pull it, and straighten it.
They can do step 1 while they are waiting, which is putting a bunch of beads on the string. This is the most beads they have to put on at one time.
The beginning is the hardest part. Start on the right side. If you put all the beads on the string on the right side, they will all swing down to make that pattern. They should be centered on the wire. Get the beads on in that order, then I’ll show you how to do the 1st stitch, so wait. The first step is unique and there are some general tips that are helpful for everyone to hear.
Demonstrate the First Few Steps and Have Students Copy You
By the time I finish cutting wire for everybody, they have the first step done. They all have the same pattern of beads on their wire.
I explain and demonstrate how to do the first stitch. Students copy me and make the first stitch on their keychain. This is what I found is the best way to facilitate this activity.
Next, we do another step of adding more beads to our wires (on the right and left sides), and do another stitch. Students copy me. This is the step and stitch that is repeated again and again until the keychain is complete.
From this point, many students can follow the pattern, and continue independently or with help from their group. I go around and help students get started, or help them them undo mistakes and get them on the right track.
Make a loop to attach the key ring. Wrap the 2 ends of wire together around a pencil to create a little loop at the top. Many students ask me to make their loop for them, so I stay really busy in this part of the lesson! They can attach the keyring to the loop themselves.
The last step is to string the extra ends of wire down each side through the gold round beads. This makes it extra strong and sturdy.
Draw Diagrams on the Board
The first step and stitch are unique, and is the trickiest part of the whole thing. After that, the pattern of beads and stitches is repeated until the keychain is complete. Diagrams of the first step and stitch, as well as the repeated step and stitch, are on the board for students to reference.
Another option is to provide students with step-by-step directions. I printed directions from online and stapled them into a class set of packets. For years I used the same directions. I can’t find the original website, but if you google “DNA keychain model lesson plan” you can find different options for step-by-step directions.
Even when I provide students with printed directions, they seem to do better and have less confusion with my method of doing a demonstration and then all doing it together to start. I observe very few students actually utilizing the directions packet when it’s provided. They just keep raising their hands for help. Of course I don’t want to perpetuate the habit of my students that they never read the directions, and expect every answer at the snap of their fingers. But I’m just working with what I’ve got!
Conclusion Paragraph
The conclusion paragraph is great for a few reasons. First, students reflect on their experience. They make connections between their models and the real molecule DNA. The models are hands-on, but explaining and describing in writing is using a different part of their brains and way of thinking to process the information.
Second, students finish making their keychains at different rates. I am busy helping them and putting the key rings on for those who are done. I can’t have students walking around the room causing a distraction or getting into trouble. The conclusion paragraph is something for them to work on until everyone is done. If they can’t get to the paragraph during class time, it becomes homework.
A few prompts to get students to think about their experience:
- Describe your DNA model: what molecules are in it, and how is it put together? (What are the 6 things in DNA? The phosphate, sugar…Say in this model we used colored beads to represent the molecules)
- What are 3 things you learned from building this DNA model? Overall what did you think of the activity? (Did you like it? Were you good at it? Were you surprised? What is your opinion?)
- Why do you think DNA is called the “genetic code?” (Which part of the DNA is the genetic code?)
Stamp DNA Keychain Paper for Completion
At the end of class, I go around and quickly double check if they finished their model. I stamp the DNA Keychain Paper which shows that they finished the construction of their model. They can take their Petri dish home, finish the model, and show it to me next class for a stamp. Thy can also finish the conclusion paragraph for homework if needed.
Students turn in their DNA Keychain Paper at the end of the lesson and I can enter all of their points in the grade book. They take their keychains with them to enjoy at home, hang on a tree, or give as a gift!
Summary of My Best Tips for Success!
Sprinkled throughout this blog post and my lesson planning ideas for this project are some of my best tips. They are summarized here for your convenience. I hope they help you have a great lesson and a good day!
- Collect the beads and make a key on Day 1, construct the models on Day 2
- The petri dishes are so helpful for this activity. They keep the beads from rolling off the table when students are assembling their models.
- Each student gets an arm’s length of wire.
- Fold the wire in half. Gently straighten it with your fingernail. This helps with keeping the beads centered from the start.
- Keep the beads centered on the wire from the beginning. Especially on the first stitch. If not centered, there will be one really long side of wire and one really short side. You will not be able to finish the model this way and will need to start over.
- After the 1st stitch there’s a general pattern on each side: gold round, silver round, base, and on the other side gold round, silver round, matching base. Lace the wire through the base and the silver round.
- “Gold silver base, gold silver base, then thread it through just the silver and the base.” When I help a student with how to do the pattern, I also say this little rhyme. I repeat it a lot in the period, it helps!
- Pull gently, until the beads are touching each other. The beads should be touching after you pull a stitch together. Don’t pull too tight, or you won’t be able to make the DNA twist later. Also the wire can break!
- Avoid kinks in the wire. The wire will get kinks just from working with it, but pulling gently helps make less kinks.
- The ends of the wire will get bent. Trimming the tips of the wires from time to time makes putting the beads on easier. With an arm’s length of wire, there should be plenty extra to trim it a few times.
- With the last base pair on the DNA model, leave the wire a little loose between the last 2 base pairs. Twist a loop with a pencil to attach the keyring.
- Lace the remaining wire down through the gold phosphate beads. This reinforces the model and makes it extra strong.
Have Fun Making These Awesome DNA Jewel Models!
This is a fun lesson for many students. It is engaging, creative, and generates discussion around DNA’s structure and components. Students make something they can keep forever. They can take it home and explain DNA to their families. It is often one of their favorite and most memorable lessons at the end of the year.
Making DNA model keychains is one of my favorite lessons to teach in Biology. These beautiful models make great keychains, ornaments, and jewelry. Students can treasure them, or gift them to someone special, making it the perfect activity to do before the winter and holiday break!
I wanted to write this blog post for a long time to share this awesome activity idea! I’m excited for you to try it with your classes, I guarantee they will love it! Let me know if you have any questions by leaving a comment, I would love to hear from you!
Also check out my blog post DNA Model Keychains: An Engaging Hands-on Lesson and Fun Activity Before Holiday Break! to read more about what students learn in this lesson, why I love teaching it, the challenges, the cost, and to explore other aspects of this lesson! Check out the blog posts below to read more about me and my classroom!
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