Ordering class sets of prepared slides can be pricey. Want a fun and free way to make your own? All you need are some slides, clear tape, and some animal hair samples. Put a few pieces of hair on a slide and carefully cover it with clear tape. A couple tips:
(Below: Left image is human hair, Right image is cat hair)
Another way to get some unusual hair samples is by checking with your local game and fish department. In Arizona our Game and Fish department has skull and pelt boxes that they loan to schools for free. I had borrowed the skull box for my ecology unit and had my students compare skulls of different animals. While I had the box, I also plucked a hair or two off the pelts and made prepared slides. It was fun to look at mountain lion, bear, and coyote hair in addition to the everyday pets.
Have you made prepared slides for specimens other than hair? I'd love to hear about it! Leave it in the comments!
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It's here! The 3rd annual week of holiday cheer from your favorite TpT science sellers! There will be different promotions every day, so be sure to check back and snag the daily deal! This year's daily deals will include:
Monday: 20% off my entire store! Click here to shop
Tuesday: Download my photosynthesis flip book for free for 24 hours! Click here to snag it
Wednesday: Have you had your eye on my writing prompt activities? They are 50% off! Click here to browse the different bundles
Thursday: BOGO free on all products under $10! Buy a product, send me a screen shot of your TpT cart, and tell me which product you would like me to send you for free! Applies to items under $10, and free item must be equal or lesser value than the purchased item. Ready for your freebie? Email me at email@example.com and please allow 48 hours for your freebie to arrive.
Friday: You really won't want to miss this deal! Click here to download some amazing resources from top TpT science sellers! This link will only work until Monday December 11th at midnight, so act quick!
Thanks so much for being a follower of my blog! Happy Holidays!
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I'm excited to share with you an EASY PEASY way for students to see osmosis in plant cells! In the past, I always used elodea leaves for this lab. Elodea can be hard to find at pet stores and is a little temperamental to keep alive. This year I decided to use onion skin from a purple onion and we got awesome results!
I used this lab BEFORE I taught any vocabulary such as osmosis, equilibrium, hypertonic, hypotonic, or isotonic. I wanted students to visually see what happens to cells in fresh water vs. salt water before I threw any vocabulary at them. Students were really excited to see the cells change within a matter of 60 seconds. Here are a few tips when doing this lab for the first time:
1. You cannot use the dry layers of the onion skin. You need to use the very top of the purple fleshy layer. It can be a little bit tricky to get a specimen that is thin enough, so I decided to do it myself and hand each kid a piece. I took metal tweezers, gently pushed them under the purple layer, and slid the tweezers out so a small flap of onion skin was loose. I peeled it off, handed it to each kid, and they set up their own wet mounts. No dye needed!
2. Have students make drawings using fresh water first. After they finished their drawing, they switched to salt water. Make sure your salt water solution is pretty saturated.
3. Tell students to wait at least 2 minutes before drawing the salt water image, because sometimes it takes a little time for the cytoplasm to shrivel up. Below are images of the onion cells in fresh water (left) and salt water (right) on 100x magnification. We had a discussion on whether or not the cell wall shriveled as well. Students automatically said yes, because the cell wall is almost transparent and harder to see. Once I told them to switch to high power (400x) they were able to see the cell wall more clearly and realize that the cell walls were still intact, while the membrane and cytoplasm shriveled.
Tomorrow we are going to follow up with the discussion of what happened and why. Students will take notes on osmosis and we will relate it to real world situations such as: Why can't I drink salt water if I'm stranded on a boat in the ocean? Why is my contact lens solution saline instead of pure water? Why do grocery stores spray the produce with water? If you want a quick worksheet to use as a formative assessment to follow this lesson, check out my tonicity and osmosis worksheet in my TpT store HERE.
I hope your students enjoy the lab as much as mine did! Other than having my classroom smell like onion for a day, it was a total win!
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As fun as prepared slides are, students always LOVE looking at living organisms under the microscope. I generally order mixed protist specimens from Wards or Carolina Biological, but this year I didn't get an order put in on time (if your district is like mine it often takes months to get things ordered and delivered...) Since I didn't have anything for my students to look at, I decided to make a hay infusion. It turned out great for what I needed.
Overall, here are the pros and cons of doing a hay infusion:
Before using the hay infusion, have your students practice using the microscope with prepared slides. If students are comfortable with how to focus and scan, it makes it much easier when they are looking for things that are swimming around. We began the class with learning how to set up a wet mount slide using an elodea leaf. Once they got the hang of it, they cleaned their slide and took a sample of the pond water.
Here is a video I took under 40x magnification:
and 100x magnification:
Although there weren't a variety of species to see, students were still pretty excited to see them swimming around. I wasn't able to identify which type of protists we had- if you had honors or AP students it might be fun to give them a protist dichotomous key and see if they can figure out which species they find. Overall it was a success and didn't cost me a cent!
Why the nucleus isn't King of the castle
Ever since middle school when students learn about cells, they are taught that nucleus is the control center of the cell. They hear that the nucleus is "the brain" and in charge of all cell functions. When teachers do the cell-as-a-factory analogy, the nucleus ends up being the boss. This is not technically true... while the nucleus houses all the information the cell needs to complete different tasks, it isn't in charge of when that information is used. We need to make sure students understand why cells do the things they do, and it all comes down to cell signaling.
Cells complete cellular processes when the cell membrane gets a signal from the outside environment. Once the signal is received, then the cell will respond by using the genetic information in the nucleus to carry out the task. That task will generally keep going until the signal is terminated. Here are a few examples:
How to get students thinking:
This can be a tricky concept to introduce to students. High school students don't usually understand how the cell operates as a whole and communicates with the outside environment. A great way to introduce the topic is by posing them these questions: "Are identical twins truly identical? Is it possible for one twin to get cancer while the other does not get cancer?" Most students will say yes, this is possible. But if they have the same genes, how can this be? Our cells are not pre-programed to behave based on our DNA. Genes are only regulated based on signals from the environment. Many students also get confused when we talk about "the environment," because they are so used to hearing this term used in ecology. Make sure students understand that the cell has its own environment within the body.
The moral of the story:
Do you want your students to read an article on this topic? Check out this close reading article I wrote available in my TpT store. It is a 3 page article with reading comprehension questions at the end for students to answer. The article covers an overview of: proteins and the central dogma, the lipid bilayer, and epigenetics. It does not cover the details of the types of cell signaling. I believe it is written at a level where most high school students can fully understand the concept of cell signaling and the cell membrane.
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One comment I frequently hear from biology teachers is "My students keep mixing up mitosis and meiosis." I had this problem for many years (the first 5 years of teaching to be exact). During my cells unit I would teach both mitosis and meiosis. I would begin by teaching them both separately, and then had worksheets and activities that compared the two. But when I would give the unit test, it was clear the students still confused the two. I needed to do something differently.
After teaching middle school for 5 years, I switched to a high school near my house. When we got to the cells unit one of my colleagues suggested only teaching mitosis, and waiting to teach meiosis until we got to the genetics unit. Light bulbs kept going off in my head. The more I thought about it, the more sense it made.
So I tried it. At the end of my cells unit (after teaching organelles, membranes, and cellular energy) I would teach mitosis. When I would test them just on mitosis they would score well, because they didn't have both processes in their head to get confused. Then, after Christmas break when we got to genetics, I would teach meiosis. It made so much sense because:
By the time I quizzed the students on meiosis they were experts on cell division. If your school gives you some freedom with the order of your curriculum, try teaching it this way! You won't regret it.
BONUS! If you want a fun way to make sure students understand the differences between mitosis and meiosis, try this FREE bingo game in my TpT store! Bingo is a great way to review scientific vocabulary. In this game you will call out the definitions and students will cover up the words on their bingo cards. You can download this product free in my TpT store HERE. Enjoy!
This blog post is all about why I think Cornell notes are beneficial for students, and tips on how to make them easier for teachers. If you don't want to read my background story on how I came to love them and you just want the nitty-gritty, skip to the bottom of the post :)
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My first year teaching was at an AVID demonstration school. If you are familiar with the AVID program, they require students to use Cornell notes during class. I was fresh out of college and had never heard of them before. I was really excited to use interactive notebooks and to be honest I wasn't thrilled with having a set note-taking format I had to use. It felt like I spent the first month of school telling students what to write on the left side of their notes, and what to write on the right side. Getting them to write summaries was like pulling teeth. BUT, after a couple of months things got easier, and students got better at knowing what to write. Eventually students enjoyed having structure instead of messy note pages. I tried my best to make sure my powerpoint slides had clear questions and bolded vocabulary so students knew exactly what to write and what was important. I initially tried to get students to write the summary for homework, but I soon realized they just weren't going to do it. Enter plan B. Instead I would go back the next day and have them review their notes and write the summary for bellwork. It was a great way to refresh their memories on what they learned the previous day. Then I would call on 2 or 3 students to read their summaries out loud, which increased the stakes for writing in complete sentences and explaining things in their own words, not just regurgitating vocabulary words and definitions. Often times students would even call each other out, and say things like "You forgot to answer the essential question!" By the end of the school year my little 6th graders were champs at taking notes.
Fast forward 10 years and I now teach a class of seniors who are taking college biology through duel enrollment. One of the entrance requirements to this duel enrollment course is for students to have been in AVID all 4 years of high school. It has been amazing to see them take notes without asking, and not just during standard lectures. We have had multiple guest speakers visit our classroom, and students automatically set up a notes page, write down notes and questions they have throughout the presentation, and summarize what the speaker taught them. All without groaning. THAT, my teacher friends, is amazing to see.
So in summary, here are a few things to take away...
Why Cornell notes are good for students:
When I moved up from teaching middle school to high school and was looking at my new curriculum I saw the term "keystone species" and scratched my head. It was a term I had never heard before and didn't remember learning in college. After learning about the terms keystone species and trophic cascades I fell in love with ecology a little more (if that is possible). These topics are so fascinating to me and I love teaching them to my students.
If you aren't familiar with the term (like I was) then here is the gist: A keystone species is a species that has an unusually large effect on it's ecosystem. Other species in the ecosystem rely on them to keep everything in balance. When the keystone population is disrupted, trophic cascades can occur. A trophic cascade occurs when predators limit the density and/or behavior of their prey and thereby enhance the survival of the next lower trophic level. I explain to my students that it is like a domino effect- once one part of the food web gets disrupted, everyone else will be effected in some way as well.
I have created and found some really good resources that you can use to introduce or reinforce these concepts:
The presentation I use in my classroom is available for download in my TpT store. I use this after I have already covered food chains and webs. This includes a 16 slide presentation (in both powerpoint or SMART notebook) and 3 writing prompts to accompany the lesson. You can download the lesson HERE.
HHMI Biointeractive's website has some KILLER biology resources. (Side note: If you haven't checked out their evolution resources, please do it now! You won't regret it!) They have a great video on keystone species and trophic cascades that is 19 minutes long. You can find the video HERE and there is a student worksheet that can be downloaded HERE.
Want to include some literacy in your unit? Biology corner has a reading article with questions on keystone species. You can find it HERE. It would be a great homework assignment or sub plan if you are in a pinch.
Another great video for this topic is called "How Wolves Change Rivers." It can be found on Youtube HERE. The video is about the re-introduction of wolves to Yellowstone National Park, and the impact they made on every other species in the ecosystem. It also takes it a step further and talks about how abiotic factors (such as the rivers) were affected as well. This video is only 4 minutes long, but is full of information so I usually show it once, have a class discussion, and then show it a second time to make sure they understand everything.
This is a fun topic to teach, so don't skip it when you are teaching ecology! It brings up great student discussions!
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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!
I know the term "open note test" makes some teachers shudder. Many teachers are completely opposed to this idea. I get it. We love our content areas and want students to retain the information and really know it. How dare students not remember information from my AMAZING lesson on cell membranes?! This is how I picture my students going home to tell their parents about today's science lesson:
But seriously, as engaging as I think my lessons are, studies have shown that students only retain 30-40% of information they see and hear. That leaves 60-70% of the information to be forgotten. I want my students to use their resources in order to become more familiar with that information they would normally just forget. Here are a few reasons why I let my students use notes on tests:
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Becca of Science Rocks
Hi, I'm Becca! I've been teaching science for 10 years at both the middle and high school levels.