Even though I have taught life science most of my career and not physical science, I still feel it is important for students to understand polarity and electronegativity. If students don't understand polarity, they won't understand why the cell membrane has a hydrophobic and hydrophilic region. Understanding polarity also helps them understand protein folding and so many other macromolecule concepts. Because of this, I spend time before my cells unit reviewing the periodic table, bonding, and polarity. Here are a list of some resources you may find helpful!
The website Middle School Chemistry has a ton of free chemistry lessons and labs aimed at lower secondary grades, including this one on why water is a polar molecule. You can check out the lab here.
This resource is a cartoon called "The Bare Essentials of Polarity" and uses polar bears and penguins to help students visually understand polarity and electronegativity. I use it every year and get so many "ah-ha" moments by the end. You can download the cartoon here.
Similar to the cartoon listed above, I created this review worksheet that uses a tug of war as an analogy for polarity. It would be a great homework assignment following your polarity lesson. You can check it out here.
If you have access to computers, PHET has a free interactive website where students can play around with and observe the polarity of different molecules. You can access the interactive here.
Want to add a little coloring to your polarity lesson? Check out this polarity color-by-number activity to give your students a bit of a brain break. You can find it here.
My friend at Science with Mrs. Lau created this free electronegativity reference page you can print and have students keep in their binders. You can download it here.
I haven't tried this last lab, but it looks like a blast! Students use food coloring, paper, and shaving cream to make observations about polar molecules. You can check it out here.
I hope one or two of those links are useful to you! If you have any other favorites, drop them in the comments, I'd love to check them out!
Ahhh the biogeochemical cycles. They are vital to life, but students don't typically enjoy learning about them. They usually know the water cycle by the time they reach high school, but struggle with carbon, nitrogen, and phosphorus. I've rounded up some resources you can use to spice up your chemical cycles unit. Don't forget to repin this blog post for later by clicking here!
1. Calculate Your Water Usage- Since most students already know the water cycle, don't spend a ton of time on it. Instead I focus on their water usage. Many students will think you are crazy when you tell them it's not sustainable to take 20 minute showers. This website is really user friendly and gives students a break down of their water usage and compares it to the national average.
2. Take A Ride Through The Carbon Cycle- In this activity, students will go around the classroom visiting different stations where carbon is found in the carbon cycle. At each station students will grab a tracker (small piece of paper that tracks where they have been) and will roll a cube that will determine where they go next. At the end students will discover where the most carbon is stored in the cycle. Download it HERE.
3. Lake Nyos Article- Throw in some science literacy with this article titled "Killer Carbon." Lake Nyos is a lake in Africa that formed inside a volcanic crater. Over time carbon dioxide was building up in the lake. In 1986 the lake eventually overturned, suffocating everyone within a 15 mile radius. This lesson includes a link to a national geographic video that grabs student attention, a close reading article with questions, and a demo demonstrating how carbon dioxide gas is more dense than air (hence the suffocation). All you need are birthday candles, baking soda, and vinegar. Download this lesson HERE.
4. Nitrogen Cycle Interactive- Of all the cycles, nitrogen seems to be the trickiest for my students to grasp. I've found this website to be helpful walking the students through the cycle. I like that it doesn't go into specifics about NH3, NO2, and NO3 but just differentiates between N2 and other usable forms of nitrogen. You can find it here.
5. Crash Course Video- If you are a veteran science teacher, chances are you have come across the Crash Course videos. Here is a link to one on the phosphorus and nitrogen cycles. I've found Crash Course videos to be GREAT for honors/AP kids, but my lower kids (and especially English language learners) struggle because he speaks fast. Preview it and see if you think it will work for your kids.
6. Make a Poster- It is nice for students to understand the cycles individually, but even better if they can link them all together. Put students in groups of 2-3 and give them a piece of butcher paper. Ask them to make a diagram that includes all the cycles. Hopefully by the end of the activity students will see that multiple nutrients cycle through organisms. Here is a sample diagram:
7. Biogeochemical Cycles Review Worksheets- Lastly, it never hurts to review review review. Here is a set of 5 worksheets I created for the cycles. There is one worksheet for each cycle, and the final worksheet is titled "Name That Cycle" where students need to identify the correct cycle it is referring to. You can find them HERE.
Hopefully this helps! If you have any other tips or resources, leave them in the comments!
Okay, so you can tell by the title of this blog post I'm a biologist and not a chemist. (Chemistry teachers, please don't send me hate mail!) Honestly, I don't love chemistry and I don't love teaching it. BUT, I realize how important it is for students to understand biochemistry before I dive into a fun enzyme lab. There have been years where I thought "screw it, I'm just going to talk about macromolecules and cells without reviewing atoms and bonding." Oh was I sorry. Most of my students didn't have a strong enough chemistry background to understand polarity without reviewing bonds. Although most of my students took chem-phys the previous year, they didn't understand how the chemistry they learned prior could apply to biology. So my advice is to take it slow, review the periodic table and bonding, have them build models, and really understand the structure of the 4 macromolecules before moving on in your cells unit. Once you get to membranes, they will understand them so much easier if they understand lipids. Once you get to DNA structure they will understand why it runs from 5' to 3' if they understand the structure of a nucleotide. They will also understand DNA replication and the enzymes involved so much better if they understand protein structure and folding. Have I convinced you yet? I hope so. Here are a list of fun ways to teach macromolecules and deepen student understanding:
1. Build Atomic Models. I'm lucky enough that I have access to model kits. I have my students build models of all the macromolecules. The best is when they can each build an amino acid, link them together, and see dehydration synthesis with their own eyes. Check with the chemistry teacher on your campus and see if they have kits you can borrow for a few days.
2. Emphasize Protein Folding. Lets be honest- of the 4 macromolecules, proteins are the rock star. It's so important that students understand how and why proteins fold, and the consequences of them denaturing. My school purchased a kit called "protein toobers" where students pretend the "toober" is a long chain of amino acids. (The activity can be purchased HERE. I am not affiliated in any way with this company). Students add thumbtacks (side chains) and then have to fold accordingly. For example, if white thumbtacks are hydrophilic and yellow thumbtacks are hydrophobic then they need to fold the toober so the white thumbtacks face out and the yellow thumbtacks face in. It is fun for them to see that each group's protein is folded differently based on the order they placed the thumbtacks. If you aren't able to purchase this kit, I think it could easily be replicated with pipe cleaners and pony beads (click here to check out a similar product from Science with Mrs. Lau!)
3. Use Videos. It is always helpful for students to hear things explained more than once and in a variety of ways. Find videos that will help reinforce concepts already taught. Amoeba Sisters always have great videos and worksheets that go with them. Here is a link to the video on biomolecules and the associated worksheet.
4. Engage with Labs! There are a bunch of fun labs out there on macromolecules, especially enzymes. I love this liver enzyme lab from biology corner. Students will see how changing temperature and pH will affect enzyme reaction rates. It's not the most fun lab to clean up after, but it's inexpensive and fun for the students. You can buy a tub of chicken liver from the grocery store for less than $2 and that will last you the entire day. Tip: I've found I get the best results when I puree the liver in the blender instead of just cutting it into pieces.
5. Use Review Activities and Games. I have never met a student that didn't love puzzles and games. It is way more fun to use these as formative assessment tools opposed to a study guide. I have a few available in my teachers pay teachers store I think you will enjoy! One is a macromolecules tarsia puzzle (pictured) where students have to pair up words with their definitions. Another option is a memory game where students flip over 2 cards at a time to try and find matches. I also have a flip book which is a fun review tool for interactive notebooks. Don't miss my macromolecules bundle where you can buy them all at a discounted price!
What other fun ways do you teach macromolecules? Leave them in the comments!
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pH.... one of those chemistry topics that us biology teachers get to teach. In biology I don't make my students calculate pH and pOH values, but they need to understand what pH is and why maintaining a healthy pH in your body is so important. You may love biochemistry, or you may hate it, but either way there are plenty of resources to make teaching pH easy!
One of the first things I have my students do is make a pH foldable. As we go through the lesson, they take notes on acids and bases, and label the pH scale at the bottom. Foldables are really easy to have students make on their own, but if you are interested in a template, click here.
After students learn what pH is, I have them complete a pH lab. The lab available in my TpT store is editable, so you can use whatever liquids you have on hand. I try and find a couple acids, a couple bases, and some neutrals (especially water!). A few hints to make your lab go more smoothly: First, don't let the students grab the roll of pH paper themselves. Save yourself some money by making your pH and litmus paper go further by pre-cutting them. I cut the litmus paper in half and cut the pH paper into small strips. Students can use tweezers to dip them into the liquids, so small pieces work great. By cutting them in half I could get through the whole day with one vial of red and one vial of blue. Also, put your pH color keys in a ziplock baggie. Students always hold the wet pH paper up to it for comparison, and if it is in a baggie it won't get ruined.
Since I teach pH right before I dive into cells, this is a great time to talk about enzymes and denaturation. When the pH of our body changes, these enzymes can unfold, or denature. Once enzymes change shape, they no longer function. Enzymes are very specific, so enzymes that are in your stomach will work best at an acidic pH, and enzymes in your bloodstream will work best around a neutral pH. If you have some extra pH paper it is fun for the kids to put a piece on their tongue and measure the pH of their saliva. We talk about how there are enzymes in their saliva that start the digestion process.
Another good topic to talk about is neutralization in the body. I usually start by telling students if I drink orange juice on an empty stomach, I will inevitably get a stomach ache. Why? Students usually recognize that orange juice is an acid and the acid is causing the belly ache. Next, I ask them what do they do when they have a stomach ache? We talk about Tums and Pepto Bismol, and how the alkaline medicine neutralizes the acid in my stomach. It is also fun to talk about bee stings vs. wasp stings. Bee venom is acidic, so putting baking soda on it will help take the pain away. On the other hand, wasp stings are alkaline, so baking soda won't help at all. Instead, putting vinegar or another weak acid should help with the pain. Students are always find these topics engaging and try and come up with other situations where they have needed to neutralize their body pH.
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