Explain the Forces

The first day I introduced forces, I also did this worksheet with the kids. We all discussed it together to come up with the answer.  I would write the answer down on my paper that the kids could see on the projector, and they would also write the answer down on their papers.  The last part I had them do themselves.  It's a pretty self-explanatory worksheet, so you can let your kiddos do it on their own if you want.  My reasoning for doing it with them was to have a little more guided practice to let them become confident in the idea before they did their own worksheet.

Again, disclaimer: This is not mine!  I found this on one of those wonderful teaching websites with free worksheets, but I wasn't good enough to trace my sources so I can't link you to the original website.

Get the worksheet at the bottom of the page.

I had a few kids telling me that was their car, and asking how I got a picture of it. :P

What is a Force?

I have loved this unit with the 8th graders.  There's something concrete about this idea that the kids can really hold on to.

To start out this unit, I first introduced the fact that

a force has both magnitude and direction.

I started out by holding a book up in front of me, then quickly letting go and catching it again lower down.

Question:  Why does it fall?
Answer: Gravity.
Question: Gravity is doing what to the book?
Answer: pulling it down.

Okay, so now we know that there is a force of gravity with some magnitude in the direction towards the ground.

Now the book is placed on a table.

Question: Is there still gravity on this book?

I got some weird looks with that.   . . . . . No?  . . .  Yes? . . . . I don't really know, but I think so, but it's not moving down. . . .?????

When the kids say "no," my eyes get real big and I say, "What?? There is no gravity anymore??"  And the kids say "okay, yeah, there is."

Question:  Then why is the book not falling down?
Answer: Because the table is in the way.

Oh!

Introduce this image on the smart board:

So we know there's gravity pulling it down. (Draw downward arrow).  But the book isn't falling through the table, so the table must be pushing up on the book. (Draw upward arrow).

HuUh??!?

Yes.  The table is pushing up on the book.  At this point you take the book back into your hands.

Question: Am I holding the book up with a force?
Answer: Yes.
Question: Then doesn't it make sense that the table also has to hold the book up with a force?
Answer: I guess so.

Then you do a whole bunch of other examples demonstrating the forces and which direction they are going. Examples can be cars, balloons, something falling (this was done to introduce the idea of air resistance), other things sitting motionless.

Now you introduce the idea that you can combine forces to find a net force.

SCENARIO 1

Here's a wonderful little picture analogy.  I chose a girl in the class to be the first person.  Sammy* (*names has been changed) is driving along the road when suddenly she runs out of gas.  She gets out and sees a gas station at the end of the road so tries to push her car.  But the car is too heavy for her to push and it won't budge.  She calls her friend (motion to Sammy for her to give her desired friend's name), Brittany*.  Brittany comes and tries to help, but they are both still not strong enough to push the car.  They then call a third friend (motion again for them to choose a third comrade) who comes and they all push with all their might.  They're finally able to get the car rolling.

Truth:

Students are more likely to listen when you use their name for an analogy.

Kids can easily see that because there are three people there is more force and the car will move.

Do lots of examples like this where you practice adding the forces, stressing that the forces are all going the same direction so you can add them.  Your answer must have both magnitude and direction.  I don't want "24N".  I want "24N ->"

SCENARIO 2

Tug-of-War.  Who doesn't love a good tug-of-war?

Team A is pulling with a combined force of 20N <-- to the left.  Team B is pulling with a combined force of 30N --> to the right.  

Question: Are the teams pulling in the same direction, or in the opposite direction?

Answer: Opposite direction.

Question: So do you think we're going to add their forces or subtract their forces?

Answer: subtract.

The net force is 10N --> to the right. 

Question: Why is the rope going to the right?

 .. . . pause while students try to figure this out . . 

timid student answer: because the team on the right is stronger?

YAY!  (remember that this is SPED, so kids need time to process answers). 

More tug-of-war examples with net forces to the right, to the left, and a net force of 0.

More examples like this on the board where both I model and the kids practice as a group:

Remember, the answer is 4N -->, not just 4N.

Independent Practice

Disclaimer, this is not my worksheet.  I found this fabulous worksheet online that I thought was just perfect for what we were doing.  I don't remember what website I got it off of, but it was one of those great teaching resource websites with free worksheets.  

To get worksheet, click here.

I printed the first two pages double sided for this day.  I printed pages 3-4 for another day to keep up practice.

Skeleton Reconstruction Results

My kids did a great job!  They loved this.  This was a really good learning opportunity.  My favorite part was showing them the pelvic bone and the femur and demonstrating how they fit together as a ball-and-socket joint.  That one was a favorite.  What other opportunity do kids get to manipulate real bones?

Just finished.  You can still see the glue still wet on some of them. 

Owl Pellet Skeleton Reconstruction

The last step of our owl pellet lab is here!  (See part 1 and part 2.)

The kids are taking their washed bones and gluing them into a complete skeleton.  For their reference, I'll have the following image on the smart-board for them all to reference throughout the lesson.

Click here for image.

The rubric requires the following things: bones placed correctly, missing bones drawn in, bones labeled correctly, neatly done.  The kids and I will work together beforehand to determine what exceeds expectation, meets expectation, and doesn't meet expectation for each criteria.  

In the end, it will look something like this.  This is my example I did for the kids to look at.  

You can already see there are a few scientific terms I'm not worrying about for my sped kids: mandible (jaw), metacarpals (fingers), metatarsals (toes), innominate (I'm using pelvis instead), and I'm not doing sacrum at all.

This should be lots of fun tomorrow. I'm excited about it. :D

Middle School Minute

Middle Schoolers can say funny things some times.  I don't catch all of it, but here are some snippets from the past several weeks:


Ms. L is explaining that the class is going to act out a deer population.
Student A: I'll be the deer.
Me: I'll be the wolf that eats you.
Student B: And I'll be the dinosaur that eats you.


Me: Does everyone understand the assignment?
Student 1: Yeppidy-yep.
Student 2: Stop saying Yeppidy-Yep!!!


After the state science test
Me: So how was it?
Student 1: It was hard, miss!
Student 2: It was okay.
Student 3: Miss, it was so easy!
Student 1: Easy?  What?
Student 3: Well, that's because I pay attention.


Student:  Miss, look at this photo I took of a snake yesterday.
Me: Wow. That's a cool snake.
Student: And here it is with blood coming out of it.
Me: Um. . . that's gross. I don't want to see that.
later
Student: Want to see the picture again?


Me: What's your favorite thing to do?
Student: Sleep.
Me too, buddy, me too. 


Student: They're coming out with a new spider-man movie in a few years.
Me: That's cool. Did you know they're coming out with a new Beauty and the Beast movie?
Student: What's that?
Me: Beauty and the Beast?  You do know that story, right?
Student: No . . . Oh, wait, I know the song.
Me(excited): Which song?
Student: You know, that one Justin Beiber sings?
Me (deflated): No . . that's Beauty and the Beat.  That is completely different.


Student 1 to Student 2:  How old are you?
Student 2: 13
Student 1: . . . when you're 20, you're going to die.
Student 2: Why?
Student 1: Because I just decided.


During lesson on evolution and the idea of common descent:
Me: So, it's like your grandpa had a tail, and your cousin became a chimp, still with a tail, and you became a human, who lost his tail.
Student: . . . My grandpa doesn't have a tail. . . ?


Student: *disgusted noise* uh! My bag smells bad.  It smells like cheese . . . from my socks.


Student: Miss, why don't you ever wear skirts?  I like skirts.
Me: It's just easier for me to wear pants most days.
Student: Hm.  Well, I like skirts.
(days later)
Me: I wore a skirt today for you.
Student: It's a long skirt.  Long skirts aren't pretty.

Bones, Bones, Analogous Bones.

I loved this lesson.  I felt like it went really well, was engaging, and the kids loved it.

We just finished our owl pellet dissection.  The bones are all out.  The next step is for the kids to organize the bones into a skeleton.  I felt like they would do much better at that if we first learned what a normal skeleton should look like, and cover a few standards in there at the same time.

I also taught them a few new skeleton terms.

Words most of them already knew:  skull, ribs
Words that were new: vertebrae, humerus, radius/ulna, pelvis.
Generic words I used: fingers, leg bones, toes.

To start with:

The Bell Ringer:

Examples of ways the two species were similar are: two legs, two eyes, no hair (it's hot!), long legs (one to run from predators, the other to reach food)
Examples of ways the two species were different:  Island A may have camouflage. Island B may have long neck.


I kept referring back to this throughout the lesson when kids would give me weird looks.  I'll explain as I go.


Here is a human skeleton.  We started by pointing out different parts of the skeleton and having the kids feel for their own bones––feel your ribs, find your sternum, feel your pelvic bones, etc.

I then had a slide with lots of different animals on it: human, raccoon, mouse, bear, bird, whale, snake, fish.

Which of these have a skeleton like the human?

We had a little vote.  It was unanimous for the land mammals to have similar skeletons.  Maybe whale, maybe bird, definitely not snake or fish.

Then I told them that, except for the fish, every single one of the animals on the board had a pelvic bone.  A reminder that the pelvic bone is your hips and your legs are attached to it.  The kids all agree that the human, mouse, bear, raccoon, and bird have a pelvic bone, because they all have legs.  But they didn't really believe me with the snake or the whale.

Next slide: skeleton images of human, mouse, and snake.  Point out the skull.  Point out the vertebrae, point out the ribs.  All three definitely have this.  Then point out the hips.  (I had to have two separate images of the snake skeleton so they could actually see the small hip bones.)

Why in the world, would the snake have hips??  I had some good hypotheses with this one, actually.  Maybe that's how the snake can lift half of itself up before it strikes?

Actually, dear students, it's because the snake used to have legs.  (Now, okay, okay, it wasn't technically a snake when it had legs––it was an entirely different species back then.  That's farther into the theory of evolution than we need to worry about now.)

WHAAAT??

This is one of those times when you go back to the Bell Ringer, and you explain that once upon a time, there were lizard-like animals.  The population got separated somehow––island, mountain, whatever.  And they needed to adapt to their new environment.  In that new environment, they didn't need legs.  If they didn't need them, would their body put in the energy to make those legs?

One thing you must stress during this lesson is that these changes didn't take place within one animal's lifetime.  The changes occur over millions of years!



Anyway, I did the same thing with a new slide of human skeleton, raccoon skeleton, and whale skeleton.

Introduce the infamous picture of comparative anatomy of the arms. 

I didn't actually use this photo, but I used a similar image in our class textbook.
Can I also say that I have always loved the bat's arm???  How awesome are those fingers?

The visual was really good for the kids and solidified their understanding.  They loved the bat just as much as I did.

We then went into independent work time. The worksheet was quite simple, but drove home the two objectives I had: (1) learn more about the skeletal anatomy, including new vocabulary words, and (2) understand that comparative anatomy suggests we all descended from a common ancestor.

Oh yeah, and throughout the lesson I talked about how this suggests we all had a common ancestor.  A long, long, long, long time ago, there was the great-great-great-great-great-great-great-great-great-great-great-great- etc. etc. - great grandfather, and from him, we got all of the animals on earth.

Again, tie in the bell ringer.  The skeleton of the two species are going to be the same.  Why would your body put in energy to completely change it when it worked great in the first place?  It might look a little different; for example, a longer neck will mean more vertebrae; but in the end, it's essentially the same skeleton.

Bring in the worksheet: (to download, scroll down to the bottom of the page)

As they did this, I had one group at a time come to our bone cleaning station.  They were to take their bag of bones from the owl pellet lab and clean them all from any left-over dirt and hair.  I'll bleach them   for a little while before our next class, and then we'll start gluing them onto poster paper to make a skeleton image of the diseased pray.

Thus, the worksheet was perfect for our purposes. It solidified our objectives and was simple enough for the kids to complete by themselves with minimal questions asked.  This allowed me to help monitor the bone cleaning station more closely.  Plus, we had music playing in the background, which always makes life more enjoyable.  Successful teaching day.

Owl Pellet Dissection

This was an awesome class.

Have you ever dissected an owl pellet before??

Do you even know what an owl pellet is?  Well, let me inform you.  An owl will swallow it's meal whole, usually.  However, it does not digest everything it eats and the only way for it to get out safely is for the owl to regurgitate it.  Thus, a ball of hair, bones, and saliva are excreted from the owl's mouth.  The pellet.

Owl Pellets for use.  They seem small, but you'd be surprised how many bones you find inside one pellet.

Sounds disgusting, right? Yeah, well, it is if you think to much about it.  I had one of my students put on a permanently disgusted face the whole time I was explaining our task for the day.  But once you get into it you kind of forget what you're working with and just focus on discovering all of the bones in your pellet.

Can I just say that I have never had an entire group of middle schoolers so quiet and captivated for an entire 40-minute period?  They loved it.

Our beginning Bell Ringer.  The writing on the poster was small, so I allowed the kids to come up to the board to get their answers.  The red answers are what they told me after everyone was done.  

One of the posters in our board.  This was a great visual to use.

This dissection was optimally placed in our curriculum.  The kids had just taken a 3-day test and were exhausted.  No one wanted to do any work (teachers included).  So I scheduled our dissection for Thursday––after the test and right before spring break (another reason no one wanted to do any work). In and of itself it is engaging, and there is so much you can learn in a single session.  Plus, the kids are basically discovering and teaching themselves, so all the teacher has to do is facilitate that flow of knowledge.

This was the poster-sized bone chart.  Each partnership also had their own bone chart to use.

All of the posters in the class that day.  Available for students to use and compare their own bones to.  

What you learn in an owl pellet dissection:

• Lab safety
• Food Webs––what is the owl eating?
• Physiology––digestion of owls and bone structure of small rodents.  Also, how many animals can an owl eat at one time?
• Scientific Inquiry––what animal does this skull belong to and why do I think that?
• Environmental Factors
• Ecosystems
• Evolution –– common descent with bone structures
• Anything you want 

This can be done in one class period, or you can extend it into an entire interactive project.  I'm going to try and extend this project out. Not only are we done with testing (thus, relaxing the schedule a bit), but this is an engaging project and many students have already asked the next steps, i.e. what are we doing with the bones we've found?

So I'm excited.  The kids are excited.  This is an excellent project for any age.  The pellets are a bit expensive, but believe me when I say they are totally worth it.  TOTALLY.  So worth it that every year our principal buys enough for the entire 7th-grade to do this dissection. 

This video came with the materials, I think.
It was a great 15-minute introduction to Barn Owl life and the Owl Pellet Lab.

Starting the dissection

They split their pellet in two so they could each work on a section.

Very cool discovery––a skull!  A hairy skull, but a skull nonetheless.

One group's pile of bones. 

The Scientific Method & Bias

The last day of Review week I decided to take all class reviewing the scientific method.  We had just finished our ecology unit, so I didn't want to take time reviewing that again.  There are probably going to be questions on the test dealing with making a hypothesis or conclusion, or evaluating bias, so we needed to spend time on that.

Because the term bias was newer to kids, this was a little slower than the last two days of review.  Basically, this day wasn't review at all, but just test-prep.

Also, notice that each day there is an additional Brain on our worksheet.  Our brains are getting stronger.  Isn't that cute????? :)

Reviewing Heredity

Review Day Two: Heredity.

This covered 2 months worth of material.

sexual/asexual reproduction
inherited vs. acquired traits
dominant and recessive traits
karyotypes
a little bit of natural selection mixed in there, too.

The kids did well on this, though not as well as cells. But there was still many good answers and good energy in the classroom.

Click here for the review worksheet.

Reviewing Cells

Two weeks ago my 7th graders and I engaged in a week-long intense review of everything we had studied this year.  The reason:  7th grade Standards Based Assessment in science was the following Monday.

Day one: Cells

Everything about cells

Plant/Animal Cell Structure and Function
Unicellular/Multicellular
6 Characteristics of Living Things
Biotic/Abiotic
Mitosis
Photosynthesis
Cellular Respiration

That's about 3 months worth of material that we went over in one day, and I was wondering how my kids would do.

Answer: AWESOME!  My kids did SO well on this review and it really made me so proud as a teacher.  The only thing they had trouble with was unicellular/multicellular, but we never spent much time on that and they're big words and if you have a learning disability and can't read very well in the first place then big words like that will scare you off.  Yeah.

We spent half of the class going over everything and then I gave them the other half to complete the review worksheet, which can be downloaded at the bottom of this page.