Browsing Tag

science lesson

Your Tried and True Strategy to Teach and Troubleshoot Punnett Square Examples

punnett-square-examples-blog

As soon as I start my heredity unit with my middle school students, someone asks the question, “Why do I have blue eyes and both of my parents have brown eyes?” Without fail. It’s not a super simple answer when they’re just learning about heredity. Students have to learn how to complete a Punnett square. I am always so excited to show them Punnett square examples of how this eye color phenomena actually happens!

Some kids really get it and others looked at me like I am an alien. It took a couple years for me to realize teaching Punnett Squares can be tricky because they seem so simple. When I really took a look at why some kids were struggling, I realized Punnett squares are a little more complex that I originally thought.

So many things that can go right and wrong. Even kids who complete the Punnett square correctly don’t always know what the information is trying to tell them. So let me help walk through a few tips and tricks that have helped me! 

What Are Punnett Squares?

punnett-square-examples

Punnett squares are a diagram showing us all the possible genetic combinations of offspring created by two parents for a specific trait. In other words, it helps us predict the likelihood offspring will have specific traits. Can two parents with brown eyes really have offspring with blue eyes? Simply, yes. Getting kids to the place where they can answer this on their own takes a bit of work.

The Secret Sauce to Students Getting It

There’s a strategy to teaching Punnett squares in a way that makes sense to your students. The last thing you want to do is start by working through several Punnett square examples. Although this works in theory, there’s a lot of background students need to complete and collect information from Punnett squares.

Focus on Vocabulary!

Do not skip this! Kids need to know a lot of vocabulary to learn Punnett squares well. Strong vocabulary knowledge gives students the ability to set up simple and complex Punnett squares and the understanding they need to analyze the information they find. 

I’d suggest teaching the words trait, offspring, allele, dominant, recessive, homozygous, heterozygous, dominant, recessive, genotype, and phenotype. 

Spending time on this vocab will result in stronger science students who are ready for high school! 

Don’t be the teacher who moves right from vocabulary to Punnett square examples. There are so many small mistakes students can make that will really throw them off later, but being able to make sense of Punnett squares in their head before you actually teach it helps so much! Click here to find this investigation and more resources to teach Punnett squares!

Be intentional about Punnett Square Practice Problems

From setting up Punnett squares to analyzing what kind of information they’re telling us, be intentional about how you work through Punnett square examples. Scaffold each step and be sure your students are ready to move on before introducing the next skill. Don’t just give them Punnett Square practice worksheets. Guide them through every step.

Punnett Square Setup

I’m going really elementary here. Ready? Draw a square and then, starting in the middle and a little bit above the top, draw one line vertically separating the square into two equal rectangles. Next, starting a little to the left and in the middle, draw a line horizontally. This creates four smaller boxes and splits both the top and the left side into two sections as well. 

One set parent allele goes on the top; one letter above each box in the outside spaces. The other set of parent alleles goes on the left side; one to the left of each box in the outside spaces.

punnett-square-example-gif

How Do You Do Punnett Squares?

Each one of the parent alleles on the top of the Punnett square falls and is written into the two boxes below it. Then, each letter from the side scoots over and is written in the two boxes to the right. It’s kind of a drag and drop. 

Your capital letter is the dominant allele and the lowercase letter is the recessive allele.

Another great way to explain this is to tell students to think of it as the distributive property in math. When you have 2(4x+y), you distribute the 2 outside of the parentheses into the 4x and the y. This turns into 8x+4y. Students distribute the letter outside of the Punnett square, the parent allele, into each box. You can see this in the color coded GIF!

Be sure to tell students the capital letter always is first in an allele pair. No matter what. 

So, What Do Punnett Squares Actually Say?

Once we’ve ended up with two alleles, one from each parent, in each box and completed the Punnett square, we can answer the question: what are Punnett squares? These alleles are the possible allele combinations, or genotypes, the offspring can inherit from the parents. 

how-to-do-a-punnett-square

Genotypes are different from phenotypes. Genotypes are the allele combinations, while phenotypes are the physical expression of those alleles. While a Punnett square can have BB, Bb, and bb genotypes, it only shows physical expression of brown and blue eyes. 

The example we walked through shows you why vocab is so important! Students really need to know how all these words work together in order to complete and draw information from Punnett squares.

Kids Still Struggling? Here’s some troubleshooting help!

While students are working, pay attention to what they’re doing. It’s easy to sit and grade or answer emails. Don’t do it! Until your kids have a good understanding, walk around, check work, and correct as needed. I explain how why scaffolding is so important in my blog post Five Easy Tips To Teaching Heredity In Middle School.

These are some issues I’ve run into while teaching Punnett square examples and how to remedy them.

Punnett-square-practice-worksheets-bundle
Get seven full days of no-prep lessons to use in your middle school classroom so you can save time and energy planning your Punnett Square unit!

Students only put one allele inside of each box.

It’s possible that there was some miscommunication (or not listening) when students were learning where to place alleles on the Punnett square. If you see this with a few kids, pull them over and reteach or do a few more examples. If you see this a lot, reteach everyone. Do more examples together. Employ the I do, we do, you do strategy. Use whiteboards (maybe even in pairs) for quick checks. Make practice stations where struggling students can work with and listen to conversations their peers are having.

Students don’t know how to analyze a Punnett square.

For whatever reason, teaching how to read and analyze a Punnett square is overlooked. Be sure to scaffold your Punnett square instruction. Complete a few simple Punnett squares, then ask what genotypes and phenotypes a few Punnett square examples show. Next, ask something like, “what percentage are heterozygous?” Or, “What is the possibility that the offspring will have freckles?” and specifically teach students how to find answers to those questions. We often forget that we’ve been doing this so long it’s easy! Students are brand new to this. Give them the proper support to be successful.

Students are just lost.

Remediate vocabulary! Punnett squares are so vocabulary heavy and kids really, really need to have a good grip on it. If you find most of your students are struggling overall, reteach vocabulary. Give each word hand gestures or have them create a game. If most of your students are lost, don’t push it. Go back and reteach, starting with vocab.

I’m a huge proponent of student investigation in science. I think it’s so valuable. But there’s also value in direct instruction. If your students are struggling, sometimes the best thing to do is just tell them what to do. I can set up the coolest investigations for seasons, moon phases, and tides, but at the end of the day, there will always be a kid who tells me the earth is flat. And you can let kids investigate Punnett squares, but you’ll still have to follow up by teaching some of the information directly. It’s okay to tell kids the right answer. 

Back to our question, can two parents with brown eyes really have offspring with blue eyes? Absolutely, they can! Don’t tell students though. Be intentional as you work through Punnett square examples with them. Then they’ll be able to find the answer out for themselves!

Life Science, Middle School

Five Easy Tips to Teaching Heredity in Middle School

teaching-heredity-in-middle-school

Teaching heredity in middle school is so much fun because kids have so many cool questions about how it works! And you get to give them answers! 

“How come I have blue eyes and both of my parents have brown eyes?” 

“How come all siblings don’t look the same if they have the same parents?” 

“Is it true that cancer is genetic?”

“If freckles are genetic, are a moles?” 

Kids are so engaged and interested in heredity once you start talking about it, so you have to really be prepared because the ins and outs of teaching heredity are pretty tricky! 

So, here are five tips to teaching heredity to help you be 100% ready and for students to be successful tackling this tricky topic! 

1. Prepare

teaching-heredity-tip-1

I’m guessing since you’re reading this, you’ve looked at your standards and know you need to teach heredity. That’s the first step! Spend a little bit of time really looking into those standards and figure out what major benchmarks students need to walk away knowing. 

Emphasize your time on teaching and practicing vocabulary, Punnett squares, and a culminating project where students can see traits being passed from parents to offspring.

The most important aspect to teaching genetics and heredity is for you to learn the content. There are so many new and content specific words students never hear anywhere else. Genetics and heredity is very abstract (we see the outcome, not the process), and some students will have a hard time getting it.  

If you are unsure about the content, you won’t teach it to kids well. Then they get confused and frustrated. And you get frustrated. So spend some time to learn, or refresh, what you have to teach. Do some research and reading. Watch some Youtube videos. Write some notes to be sure it makes sense. And make sure you know the vocabulary!

Want your complete heredity unit laid out for you? Download the free Middle School Science Teacher’s Guide to Heredity so that you will save time planning and stop stressing over your heredity unit!

2. Speak Their Language

teaching-heredity-tip-2

Please don’t try and learn the latest middle school lingo. That is not what I mean!

First, as you get a handle on heredity content knowledge for yourself, try to think of ways to explain it better to your middle school students. When I was in 6th grade (pre-technology), my science teacher Mr. Zecher would draw pictures in different colors on the board as he taught and we drew the same pictures in our notebooks.

I still remember the different types of fault lines, and I kept my science notebooks for years! If you can plan for one or more of your lessons on heredity to include drawing pictures, awesome! 

Next, try to use everyday language or examples wherever you can while teaching heredity. My students could not figure out dominant and recessive alleles, so we talked about wrestlers going against each other from the same and different weight classes. Which wrestler is stronger? Which one would win in each match? How does that relate to dominant and recessive alleles? In this particular heredity lesson, my 8th graders finally got it! 

Read this blog post explaining how I compare density to suitcases! It illustrates this point perfectly!

Don’t underestimate the effectiveness of making simple connections while teaching heredity.

Want a step-by-step roadmap to help you plan your heredity unit so you can save time stressing over what to teach and how to teach it? Download your FREE Middle School Teachers’ Guide to Heredity right now!

3. Simplify Teaching Heredity

teaching-heredity-tip-3

You do not have to teach every life science standard before you start teaching heredity. Simply put, students need to know these few things, and only these few things, before they can fully understand heredity: 

First… each sperm and egg cell has 23 chromosomes and when they fuse to create an embryo, they create 46 chromosomes, or 23 pairs – one from mom and one from dad, and

Second… genes, or alleles, are located on the DNA inside of each cell. 

Consider spending a little bit of time reviewing or skimming the Cell Theory or how DNA is structured, but don’t go too deep. There is no need to spend weeks teaching every cell-related topic. 

Keeping it simple in preparation for teaching genetics and heredity will free up your middle school student’s brains to think about it more clearly without all the noise of every other lesson they’ve heard about DNA in the last month. Of course, this wouldn’t apply unless you’re expected to teach cells and DNA before your hereditary unit based on state standards.

4. Emphasize Vocabulary

teaching-heredity-tip-4

How the heck do you get a 12 year old to remember what phenotype is shown by a homozygous recessive allele pair?! 

I actually have an answer for you. Teach vocabulary. 

In my opinion, there is a lot of emphasis put on investigation in science. While that’s actually a very good thing, there is a time and place for direct instruction and this is one of them. 

Asking middle school students to learn these hard words requires teachers to teach vocabulary strategies. Front-load vocabulary by introducing it through stations, teach prefix and suffix strategies, or asking kids to draw pictures. 

Whatever vocabulary strategy you decide to use, include some direct instruction. Say the words and have kids repeat them. A “homozygous recessive allele” pair includes three new words that all need to be in the same sentence, but also sound like gibberish. Practice how these words relate to each other. 

Finally, spend a few days on practice through games, worksheets, or activities. 

5. Build On Previous Lessons

teaching-heredity-tip-5

Many students have noticed family resemblance. Maybe they have the same eye color as a parent or they look very similar to a sibling. That’s the easy part of planning a middle school genetics lesson. That’s what students observe. Use it as a launching point for your heredity unit. 

Fortunately, that’s not where we stop teaching heredity! Teachers begin the process of explaining how kids look like the rest of their family. It’s tricky because student’s can’t observe the process, just the outcome. 

The key is to give students the proper support as they learn more and more. 

First, start with vocabulary because that’s necessary for Punnett squares. Use simple, straight forward Punnett squares at first. 

Punnett Square Story Problems Are A Perfect Example

Then, add more complex concepts once you know they’re doing it correctly. Think of this like using simple addition before giving kids story problems. Your simple addition would be a Punnett square with given alleles all set for them to complete. The story problems require students to think and understand.

For example, you could say, parent one has blue eyes and parent two has heterozygous alleles and has brown eyes. Create this cross. 

The story problem is more complicated and shows the student’s knowledge of vocabulary and Punnett squares. Students need to know both to level up to the critical thinking required for a story problem

There are a lot of things to consider while planning for your heredity unit. You want students to be successful. By preparing, speaking their language, simplifying it, emphasizing vocab, and scaffolding every step, you’ll set your students up for a win!

Don’t forget to download your free Middle School Science Teacher’s Guide to Heredity filled with easy strategies, clear information, and the step-by-step order you should teach your heredity unit in! Download the guide here so you can stop Googling, curl up on the couch, and watch your favorite show without stressing!

Life Science, Middle School

How to Use Picture Books to Teach Food Chains

pond-circle-food-chain-artwork

I remember the transition from picture books to “real” books. Somewhere between The Magic Treehouse series and Hatchet, the pictures slowly disappeared from the books I was reading. And while this is a totally good and normal process, there’s something exciting about opening a book and seeing pictures. So why wouldn’t we as teachers harness that nostalgia and use picture books in our teaching? This is my all time favorite list of picture books to teach food chains and food webs!

As an Amazon Associate I earn from qualifying purchases. I earn a very small commission from items purchased through affiliated links, but your purchase price is always the same!

The Case for Using Picture Books in your Middle School Classroom

Picture books are pretty simple on the outside. What makes them a powerful tool in your classroom is that simplicity. They’re not intimidating. Whether your students are high achievers or struggling learners, they love being read to. 

What I think I love most about using picture books to teach middle school science is that it has the ability to break down, and even scaffold, content and vocabulary that can initially be tough for kids to get the hang of. But with a guided read aloud, these science concepts can easily be highlighted by the teacher and are usually emphasized by pictures. 

Without further ado, these are my personal favorite best picture books to teach food chains and food webs!

Who Eats What? 

Who eats what picture book about food chains

The name says it all. This is a picture book about food chains and food webs. I love how simple this book starts and slowly scaffolds into complex food webs. The author really focuses on the complexity of a marine food webs about halfway through, including producers and consumers. The end of the book shares about how humans can impact food webs, using the example of otters killed for their fur.

If you use this picture book to teach food chains and food webs, ask students to make a venn diagram showing the differences and similarities. You can also ask students to compare and contrast  land and marine food webs.

Pond Circle 

This is one of my favorite picture books to teach food chains. While simple, there are a lot of different directions you can go with this book in a science classroom. We open up to algae in a pond, that is eaten by a mayfly, that is eaten by a beetle, who is eaten by a frog. The food chain continues. This picture book about food chains follows one very long chain all the way up to a coyote. 

If this book is about a pond food chain, how can it be so versatile? First, and very simply, it is a basic food chain. Talk about the idea of where each organism gets their energy and how long the food chain is. The raccoon eats owl eggs. Is that the same as eating an owl? Why or why not? 

My favorite way to incorporate this book is after we’ve learned about trophic levels. I read the book once, we talk about it, and then I ask them to make a trophic level pyramid using all the organisms from the book. I love hanging their trophic level pyramids on bulletin boards because they look so good! 

What’s for Dinner? Quirky, Squirmy Poems about the Animal World

whats for dinner picture book about food chains

What’s for dinner? Is a different book than the others. There are 29 short poems about food chains and food webs. The poems are witty, funny, informative, and right on with your middle school student’s humor! Trust me, they will love it. And while these poems are entertaining, this picture book teaches about food chains and food webs with great accuracy. 

This book is fun to use in stations or a carousel type of activity. Copy the poems you want to use and hang them around the room or set up stations. Create quick questions or activities based on the poems you choose. Students will LOVE this activity and learn some stuff too! 

Check out this free food chains and food webs silly story activity designed for middle school students!

Hey Diddle Diddle: A Food Chain Tale

hey-diddle-diddle-food-chain-picture-book

I really like this book to teach about food chains because it is just a funny story. Each one of the animals has a small part and something clever to say. This picture book about food chains highlights a couple of very small food chains with great images and catchy rhymes. I also enjoy that it includes a few lines about each animal’s adaptations. It’s a very fun and clever book.

Everything You Need to Know About Middle School Science in One Big Notebook

ace-science-notebook-picture-books-to-teach-food-chains

Okay, this one isn’t exactly about food chains and food webs, but it sure is great! I use this book all the time. You’ll find every topic you’d ever need to teach about in middle school science in plain english for you or your students! I love copying this text to scaffold or accommodate for students. Each topic is written in a way that defines every word a student may not know and includes so many pictures. There is a whole section in this picture book about Interdependence and the Cycling of Energy and Matter, which is exactly where you’ll find all your information on food chains and food webs. 

There you have it. My ultimate list of picture books about food chains and food webs. Here is my challenge to you. Incorporate more picture books into your middle school science lessons. You’d be surprised at the engagement you get when you pull out a picture book instead of a text book.

Looking for a free Food Chains and Food Web activity for your science class? Check out this silly story!

food-web-activity-silly-story
Life Science, Reading & Writing in Science

What’s The Difference Between Earth’s Rotation and Revolution?

teach the difference between earth's rotation and revolution

I love teaching Earth, Moon, and Sun systems. I think it’s so cool how three celestial objects can create so many things. Sunsets, moon phases, seasons, eclipses, days, and nights. It’s caused only by Earth’s rotation and revolution. There’s something magical about it to me. But what’s the difference between Earth’s rotation and revolution?

One year, as my 7th graders and I were talking about moon phases, one asked how sunsets are made. I knew how. But I didn’t really know how. Yes, I knew that the earth spinning and changing from day to night created sunsets, but I couldn’t articulate it. 

I didn’t know, so I researched

So I researched “what’s the difference between Earth’s rotation and revolution?”. Come to find out, I knew how sunsets are made, but I didn’t have the proper word for it. Rotation.

I also realized I had been skipping over this very foundational topic of earth’s rotation and revolution when I taught about the Earth, Moon, and Sun systems. So, in all of my teaching about moon phases and seasons, I never really explained how these systems worked.

Teach your students the difference between rotation and revolution with this awesome interactive notebook template! Click here to find it!

The real difference between Earth’s rotation and revolution

Let’s first start with the basic definitions and difference between Earth’s rotation and revolution.

Rotation: The Earth is sitting in space, titled on a 23.5(0) axis. One rotation is a single spin on that axis in 24 hours. Earth’s rotation helps us differentiate between day and night. Think of how a globe moves. Two points on the top and bottom hold the globe in place and when you spin the globe, it stays in place and spins on those two points. 

Revolution: The Earth is orbiting our sun. A full revolution is one trip around the sun, taking one year. If we start a timer on June 12th, it would take 365 days for the Earth to complete a full revolution, ending on June 12th the following year. 

There is a big difference between what these words mean. One creates sunsets and tides, and the other is responsible for our calendar. 

Don’t skip teaching the foundational stuff

Photo by Aaron Burden on Unsplash

I’m a huge proponent of scaffolding science concepts (and I’m probably guilty of oversimplifying) so that students can really understand what they’re learning. I assume with the emphasis put on reading and math in elementary school, student’s science exposure is pretty limited. 

And here I was. Skipping the very foundational stuff. 

Why should you start your Earth, Moon, and Sun systems unit by differentiating between earth’s rotation and revolution? 

Students get these words confused. They both start with R, they’re both pretty specific to how planets move, and they cause completely different phenomena in nature. 

In addition to our Earth rotating and revolving, planets and moons do the same thing. Our moon phases and eclipses are created by the moon revolving around the Earth. The high and low tides are caused by both the revolution of the moon and the rotation of the Earth. 

Get them familiar with rotation and revolution early

Students should fully understand the terms rotation and revolution before they determine what is caused by each phenomena. This interactive notebook is the best way to give your students a hands on opportunity to see and remember the difference between Earth’s rotation and revolution.

Your students will see the words rotation and revolution in their reading and on websites as they learn. Addressing the difference up front is such an easy way to scaffold their learning and keep them from becoming confused later on. I find it best to teach earth’s rotation and revolution at the beginning of the unit. You’ll be able to refer to each word, rather than spending multiple chunks of multiple class periods trying to undo confusion. 

Do yourself a teaching favor. Before you teach moon phases, tides, and seasons, spend a day talking about the difference between Earth’s rotation and revolution. Your student’s will thank you. 

Moon phases are caused by the moon's revolution around the earth.
Earth Science, Space Science