Science

Jello Skin Model

 Ready for another food model? I love using anything edible to demonstrate science concepts whenever I can, and this week seemed to be full of food activities! Recently, in my 7th grade class, we have been studying the integumentary system. This includes the layers of the skin as well as the “stuff” inside.

We had discussed the different parts of the integumentary system in a previous lesson. Students used a diagram to label each layer and write down the function and purpose.

I did throw in one little demo that shows how oil affects our skin. The oil glands secrete oil that helps provide a barrier for our skin. First, I had students use an eyedropper to place a drop of water on their skin. We noted how the water stuck together. Then I took a cotton ball and swabbed their other hand with rubbing alcohol before putting on another drop of water. This time, the water droplet ran right off — it did not stay stuck together. The rubbing alcohol had taken some of the oil of the skin and in doing so, the skin was not as water resistant!

My students did like that demo, but obviously the food part was a bigger hit! I originally found this activity here at My Mundane & Miraculous Life and couldn’t resist trying it. 

Here are the materials needed to make the jello skin model:

  • 4 packs of Jello (I think orange works best so you can see the inside)
  • Mini Marshmallows
  • Fruit Roll Up or Fruit by the Foot or another type of fruit leather
  • Twizzler Pull n’ Peel

Directions:

I forgot to take a “before” picture of the whole pan. This is a little section left of just the jello and marshmallows!
  1. Make the jello but use the “Jiggler” recipe. (I think it uses less water and makes a firmer Jello. If you aren’t using Jell-O brand, you can find a jiggler recipe here)
  2. Let the jello set for a few minutes (until it isn’t super hot) and pour the marshmallows on top. Then let it set for at least 3 hours or overnight.
  3. Cut the jello in pieces and place the pieces on a plate upside down so the marshmallow layer is on the bottom. Each student gets a piece.
  4. Have the Twizzler Pull ‘N’ Peel and  cut into sections and the Fruit Roll Up unwrapped and ready to give to each student

As a class, we discussed what two layers of the integumentary system the model represented so far (marshmallows= fatty tissue or hypodermis and the jello = dermis)

Students then received a piece of Fruit by the Foot (but other materials would also work) to put over their jello. This represented the epidermis.

Students received pieces of Twizzler Pull N’ Peel. Some pieces were used as hairs. Students had to poke holes in their epidermis and stick the pieces in. Other pieces could be rolled up and stuck inside the dermis layer to represent sweat glands. I used plain red Pull ‘N Peel, but it would be neat to try multi-colored (I’m pretty sure that exists…) and each color could represent something else in the skin: hair, sweat glands, nerve receptors, etc.

I’ve heard of also using things like chocolate chips to represent moles on the skin surface. Creative!

The best part is, after students have completed their model, they can eat it! Delicious!

Trashketball – A Great Review Game for Any Subject!

A trash can, paper, and review questions are the only things you need to make “Trashketball” work!

It’s March Madness season. Anyone else get into this time of year? I love filling out my bracket in the hopes of predicting the most correct, and then quickly become disappointed when my teams lose. But that is the greatness of the tournament!

Both teachers and students get very into the games here at our Indiana school. Our PE teacher randomly assigns each class to a few teams in the tournament. If that time wins the whole thing, the class gets to do a special activity of their choosing. The teachers are in a pool where the winner gets a gift card (or maybe even their recess duties covered for a week!) I let the my middle school students fill out one and the top 5 or so overall get to have ice cream sundaes after lunch one day. It definitely makes watching the tournament a fun experience!

Teachers have also been incorporating basketball into their curriculum as well. A 5th grade teacher did an inquiry lab on how the angle of the backboard affects your shot percentage. Another teacher in the lower grades has a bulletin board set up in the hallway about Indiana basketball history. What a fun way to connect students to content!

Because spring break was fast approaching, I needed some review games. Often I will use Kahoot (which kids love!) but I was inspired by some crazy basketball games over the weekend to do something different. Trashketball was a game from my own middle school memories and I was super excited to bring it back to my classroom!

All you need to do this review game is the following:
  • A set of questions that can be answered in a few words (or numbers)
  • A trashcan
  • A bunch of slips of paper

I used this for my math class, so I copied down a bunch of problems that I could project on the screen. Students had calculators and scratch paper to help them.

To set up the game:
  1. Prepare questions to give to students. The best way to do this is to have questions ready to display somewhere that all students can see at once.
  2. Cut up paper into small squares. Have a lot of paper ready (you can always use the extras for next time!)
  3. Place a trash can (I use a smaller can) in the middle of the room, and students place their desks or chairs in a circle around the can. It is up to you how far students are from the can. Farther away makes the game a little more challenging! Make sure students sit equal distance from the can and no one has a huge advantage.
Here is how to play the game:
  1. Students see a problem on the screen and have time to figure out the answer (depending on the question, I gave them between 30 seconds and 1 minute) and write their answer on a slip of paper with their name on it.
  2. Once the time was up, I would tell the students, “Shoot!”During this time, students would crumple up their slips of paper into mini “basketballs” and shoot their answers into the can.
    1. Students may NOT stand up or move around during this time. I told them their “bums” needed to stay in the seats!
  3. I gave 30 seconds for students to “shoot” their answers. There are two ways to do this:
    1. Students can shoot as many slips of paper with their answers on it as they can in that 30 seconds
    2. Students can shoot up to a certain amount (like 3) in a round.
  4. When shooting time is over, the teacher grabs the can and looks through all the papers that actually made it in. Any correct answer receives one point. Incorrect answers get zero points.
  5. Students keep track of their own points and whoever has the most at the end wins!

There are other versions of this game out on Pinterest. Here is a link to another version that sounds great too!  Mrs. E Teaches Math has great ideas, so be sure to check out the rest of the blog.

Students loved the game and already have requested to play it again! It was fun, engaging, and helped students review how to do their math problems! It does create a little craziness in the classroom, but hey, it’s March Madness!

Digestive System Mini Lessons – Part 2

Here is the Digestive System Mini Lessons – Part 2 post! There are three more simulations for parts of the digestive system. If you missed the first post on this, be sure to check it out by clicking here.

Sweet Teeth

This activity demonstrates how your teeth help in the digestive process. Students receive a sugar cube as well as a small cup of granulated sugar. They fill two cups with equal amounts of warm water, placing the sugar cube in one cup and the granulated sugar in the other. Students stir each cup and watch how the sugar dissolves. The granulated sugar dissolves much more quickly than the cube, just like your teeth break up food into smaller pieces so it is easier to break down the food later.

A student stirs a cup with granulated sugar and compares it to another that has sugar cubes.
Materials needed:

2 clear cups

Water

Sugar cubes

Granulated sugar

Stirring sticks

 

Surface Area Matters – How the Villi Help the Small Intestines


Villi help absorb as many nutrients as possible. To demonstrate this, students take four cups of water and fill each with the same amount. For the first cup, students take one sheet of paper towel, fold it several times, and dip into one of the cups to absorb the water. Then students take a graduated cylinder and measure whatever water is left in the cup that the towel didn’t absorb. Students repeat this using two paper towels folded together, three paper towels, and four paper towels. The four paper towels folded together should absorb the most water, leaving the least amount behind in the cup.  Often, I follow up on this by asking, “What would happen if there weren’t as many villi to absorb nutrients?” Students agree that some nutrients may be missed! This always reminds me of the Chocolate Factory clip from I Love Lucy – without enough villi, the intestines would be like Ethel and Lucy and miss a lot of good stuff!

Materials needed:

Four cups

Water

Paper towel (9 sheets)

Graduated cylinder

 

Let the Juices Flow!

Using orange juice, students see first hand how the acids in our stomachs help break down foods. Bread is torn into small pieces and placed into ziploc bags. Then they pour some orange juice into the bag. Make sure the bags are sealed (otherwise it gets messy!) and squish the bread around. The bread looks gross, but starts to dissolve before your eyes! Students carefully pour the liquid out, leaving behind the solid “waste”, which is then disposed of in the garbage can! This activity simulates several parts of the digestive system, but especially highlights the large intestines’ job.

The “stomach acids” at work.
The “solid waste” leftover. Gross!
Materials needed:

Ziploc bags

Bread

Orange juice (or another type of fruit juice)

Waste container or sink to empty juice into

 

I do have short worksheets for all of these activities. Students fill them out to help instruct and guide them throughout the lesson. Please comment or email if you would like to have them!

While students participate in their activities, I like to walk around and ask questions, clarify instructions or just listen to how students explain things to each other.  It is awesome to see students making the connections and teaching each other!

Please use these ideas in your own classroom, either in groups like I did, or even as full class demonstrations! Have fun digesting!

Puff Mobiles – A quick STEM activity.

It’s been a blustery few weeks here in Indiana. We have gone from a balmy February to a mild start to March, but as we approach spring break, it has been cold! All this up and down in temperatures has caused some extremely windy days. Like trees blowing over, branches falling, be careful when you go outside windy days! In fact, it is snowing today, but the forecast shows temps in the mid 50s in a few days. Welcome to Indiana.

On one of those days, after the wind was howling through the night, I decided to introduce Puff Mobiles to my elective class. This activity is easy to set up, and the students love it. Before introducing the activity, I do a brief overview of wind and wind power with my students. We discuss how wind generates electricity and the wind turbine (we have lots of these in our area!) We also recall how it was used for ships and boats as the first modes of transportation.

Then we get to the fun part–the Puff Mobile.

Goal:

Students must design a vehicle that uses wind power from their own mouths to puff or blow their creation to the finish!The wind background info isn’t completely necessary for this one (but I like to include it), and it doesn’t really have a prompt or standard that it aligns perfectly with. But it is fun, works on engineering concepts and is easy to implement!

There are relatively few supplies needed, which makes it easy to prepare on short notice!

Each student (or student group) receives the following materials:
  • 3 Straws
  • 2 Paper clips
  • 4 Peppermint Lifesavers
  • One sheet of paper
  • Tape (I limited the tape to about 50 cm so students don’t go crazy!)

Not all supplies must be used, but may no other supplies may be included.

Students get 3-4 minutes to plan out and sketch a design before actual construction. I do encourage students to stick as close to their sketch as possible. They are allowed to cut the straws and paper. Paper clips can be bent and twisted however students think necessary. Students can even color their paper if you have time! Construction takes anywhere between 10 and 20 minutes (depending on how much time you have!).

Once all was constructed, we set up a Puff Mobile tournament! We pushed the tables and chairs to the side of the room so we had a lot of open space down the middle. I drew brackets on the board (March Madness style) and pulled names out of a cup so students were randomly matched up. A start line and finish line are necessary, and the race can be as long or as short as you want!

Some rules we establish for the Puff Mobile Races:
  1. During racing, the vehicles must start and remain (as much as possible) on the ground. AKA – not paper airplanes.
  2. There is absolutely NO intentional moving, blowing, hitting, kicking, etc of another mobile in order to advance your own.
  3. As audience members, students may cheer and encourage, but may not touch or get in the way of anyone in the race.
  4. The teacher is the final judge. If mobiles somehow get stuck in the corner or turned, I can tell them to pick it up, turn it around or to “unstick” it.

I think it is hilarious watching the kids belly crawl across the floor, trying to puff their mobiles all the way across the finish line!

Kids have a blast, AND my floors are much cleaner after the races!

Roller Coasters – Looking at Potential and Kinetic Energy

Who doesn’t like a roller coaster? Let me rephrase that… what middle schooler doesn’t like roller coasters? And if they don’t like riding them, I’m pretty sure they would still like the idea of building one!

This is one of my favorite activities of the year. It incorporates concepts of kinetic and potential energy, which is a big standard to cover in sixth grade, while engaging and challenging the students.

SLED Program

I definitely cannot take credit for coming up with this lesson. It was developed through the SLED program. (Science Learning Through Engineering Design) This program, funded by a grant through the NSTF, was a partnership between the SLED program directors and teachers of grades 3-6. Because the program was developed at Purdue University, many local school districts and teachers were able to be a part of developing these lessons. The focus was to increase science learning through engineering design. I worked with the SLED program and its amazing directors for several years and through it, added a bunch of awesome engineering-based projects that align perfectly to Indiana science standards. (Here   is more info if you want it!)

Before the Activity

Before starting the roller coasters, my students have learned/reviewed kinetic and potential energy. We do a lab where students “play” with wind up toys, mini circuits, bouncy balls and more, and trace how the energy is transferred in each situation.

I also LOVE showing them this video. It gets stuck in your head, so watch out! But then again, it will get stuck in students’ heads, which is fantastic!

I follow the SLED lesson plan, which you can find here

Designing the Roller Coasters

To introduce the activity to the students, we begin with the challenge: Indiana Beach wants to build a new roller coaster with a lot of loops, but wants to be as economical as possible. Can they help? Instantly, students are engaged. Indiana Beach? Roller Coasters? Hooked. However, we discuss several concepts before designing.

  • What’s the challenge? (To build a roller coaster with loops)
  • What is the goal? (The most loop diameter for a limited coast)
  • Who are we working for? (Indiana Beach)
  • What are somethings that might limit us? (Space, materials, TIME!)
  • What concepts in science have we been learning about that will help us here? (Kinetic and Potential energy!!!)
Materials used to build the coasters:
The tubing comes in packages like this. I find the 3/4″ works best.
  • Insulated pipe tubing. I use 3 ft sections cut in half. These make the “track” for our coaster. You can find them at any hardware store (Lowe’s, Home Depot) or online. You will have to cut them in half.
  • Duct tape
  • String
  • Tacks (longer tacks work better)
  • Large pieces of cardboard to secure the coasters on(think refrigerator, tv, large sporting equipment, etc. I had a connection to someone that worked in a bike shop and got several large boxes from him!

The tubing and cardboard can be reused, so you will not need to get all new supplies every year!

Once we review the materials and the goal, students get a few minutes to plan and sketch their designs individually. Next, I put them in groups of 3 (if necessary I make a group of two. Four students seems to be too many in this activity…) and together, they come up with ONE plan that they want to use for their roller coaster.

Each team gets a large cardboard piece which is propped up along the wall around my classroom. This is their roller coaster canvas. They may receive up to 5 pieces of “track” and unlimited amount of duct tape, string and tacks (although all come at a price!). Students typically need about 30 to 35 minutes to design and build their coasters (or really, that is all the time I can give them!). For the coaster, we use a marble. I do allow students to test their coasters as they go so they can make slight adjustments as needed.

While students are building:

I usually walk around during construction, asking questions such as:

  • Why did you need to make your second loop smaller than your first?
  • Why are you starting the marble so high?
  • I see that this loop isn’t working. What do you think the problem is?

Encourage students to think about kinetic and potential energy when responding!

 

Wrapping Up

Once time is up, student groups calculate their coaster’s final cost, measure the total loop diameter on the coaster, and calculate a team score. Team scores are the cost divided by the total loop diameter. Lower scores mean the coasters are more cost efficient or have a high loop diameter, which were the goals!

Finally, groups present and test their coasters in front of the class. We take a “roller coaster tour” and walk around the room. Students share their designs, their cost and their team score. Then the moment of truth… will the marble actually make it through the entire track!? I do give students several attempts, but usually there are a few groups that are unsuccessful, and that is ok! At each coaster, students put sticky notes on where they believe the most potential energy and the most kinetic energy are located–super helpful in reminding students  about these concepts!

Overall, this lesson takes me about three class periods. However, it solidifies students’ understanding on kinetic and potential energy. And it is fun! They will be talking about their coasters for weeks to come!

 

Quick Team Building or Just for Fun Tasks!

I believe that in any classroom, working as a team is important. However, dealing with others can be a challenge, no matter what the age! I like to incorporate activities throughout the year that focus on team building, but are also fun tasks for the students. These are just two of examples that are great for any grade level, any subject, or maybe even as a professional development exercise!

Marker Mayhem

  • Students are put into groups of 3 or 4 and given a marker with 3 or 4 strings attached
  • Each student may only hold the end of one string, and may not touch any other part of the string or the marker
  • Working together, students must draw a picture, write a word, etc.
The cat I drew that students tried to copy

When I did this activity, I first had students write letters, like ABC or CAT. They could talk and instruct each other on how and where to move the marker.

After the initial round, I asked the student groups to draw a picture of a cat. I drew a cat picture on the board and told the groups they should do their best to copy that picture. Right before they began, I said “You may not talk!”

Many protested initially, but when I said go, it was silent. Students were forced to communicate without words and make the best cat drawing they could.

It was hilarious watching some of the groups attempt the cat. A few looked like my 2 year old drew them (or worse), but some groups were surprisingly successful! With each round we did, groups improved on their communicating and improved on their drawings!

Straw Tower

The next activity is a simple one that uses straws and tape and that’s it! The goal is to use the materials to build the tallest straw tower possible in a short amount of time.

  • Students are put into groups of 2 or 3
  • Each group received 10 straws and about 30 inches of tape.
  • 2-3 minutes of planning time given.
  • About 10 minutes of building time given.

Before students were allowed to even TOUCH the supplies, I told them they had two minutes to talk with their partners and come up with a plan. They could sketch things out, strategize and share ideas.

Once the two minutes were up, I told students I hoped they were wise in how they spend their planning time because now they could NOT talk for the rest of the activity. I gave students 10 minutes to build their towers. And it HAD to be silent

It was very amusing watching students use other methods to communicate (and I did not allow any writing of messages either!) Hand motions, pointing and lots of head shaking were seen.

Some students had great plans that worked well. Others found their original plans did not work and that trying to form a new plan without talking was very difficult!

After the timer went off, students could no longer touch their towers. I came around and measured each tower with a meter stick to see who won the challenge!  (By the way, I LOVE using online-stop-watch. When the timer goes off, it always makes everyone in the room jump!)  

Discussion

We had a good class discussion afterwards about what was difficult and what worked well. Students agreed that making sure you had a plan ahead of time worked well. Communication is huge! If they couldn’t communicate, it made the task much more difficult to complete. We need to share our ideas, listen, and watch. If we can communicate more effectively, we can get a lot further!

These activities were very helpful in setting up how my students need to work together and communicate with each other. You can use these just for team building or class communication. And they can be done in middle school, high school, or even upper elementary grades!

Cereal Bohr Models – Chemistry

I absolutely LOVE when I can incorporate food into any of my lessons. When I saw a picture on Pinterest showing Bohr Models made of cereal, I knew I had to try it myself!

(You can see the link here from Some of the Best Things In Life are Mistakes)

Chemistry Activity

My 8th grade science class learns about the different models of the atom. We typically use the Bohr model the most, since it shows the energy levels and prepares students to understand more about electrons being gained and lost. However, it is a struggle to get students to understand the electron levels and how to correctly draw these models.

Enter cereal. Creating larger, hands-on models with yummy, sugary, colorful cereal should help them remember!

Before jumping into the bowl (get it, cereal… bowl…? My students love those kind of jokes… maybe…) I made sure to show students how we draw Bohr models. We discussed the different energy levels and took note of how the periodic table is setup so we can see exactly how many electrons can fit in each level.

Students first drew and color coded Bohr models for two different elements. This way I could check to see they understood BEFORE getting the glue out! Once students could demonstrate good understanding of the model, I gave them a plate, cereal and glue. It actually worked out that the students that had no problem understanding could independently get to work on their cereal models. Students that were still confused gathered with me so together, we could review what we had learned about atoms and how to draw these models. Then, I could walk them through the process again with the cereal!

Cereal Bohr Models!

Overall, I think it was a success. Students happily munched on some extra protons and electrons while gluing down the pieces in the correct orbitals. Simple, but effective and fun! It also makes a great, EASY bulletin board. My kind of lesson!

Crazy Catapults – STEM Project with simple machines.

I love introducing STEM projects (like these catapults) to my 8th grade students. Because this is the third year I have taught most of the students, they know my rules, and I know their tendencies. By this time, I can foresee some problems that the students could run into and avoid them. I can also try new things with these students. They won’t have melt-downs if something doesn’t go as planned! I’m also continually impressed with how many cool ideas and designs they come up with… they are very creative!

These eighth graders recently wrapped up a unit on forces and simple machines. Last year, I saw a few lesson plans that involved building catapults and thought that would be a perfect way to tie everything together. The project went fine, but students didn’t quite use the simple machine concepts like I had hoped they would. So this year, I decided to amp up the catapult plan and make better! These eighth graders love a challenge and could roll with any minor surprises!

Lesson Overview

First, we discussed a little bit of catapults history. Together, we talked about the different types that were used for various reasons. Accuracy, power and distance are all important features of a quality catapult. Knowing this information, students received the challenge to design and build a catapult that would meet the three main criteria. Launching mini marshmallows as far as possible, trying to accurately shoot the marshmallows into a bucket, and using a sugar cube to knock down stacked cups were their tasks.

The catapults were a huge hit! The kids wanted to bring in materials from home to work on them (which I didn’t allow), and had unique ideas of how they wanted their catapults to work. I will say that next year, I will have to give a few more design restrictions. Some of the created designs had difficulty with one or two stations. Trebuchet type catapults seemed to work the best for the stations I choose.

Overall, I would say this year’s catapult project went much better than last year’s. I made sure students had to identify the simple machines in their design, and even calculate the mechanical advantage. Next year, I will adjust it more (aren’t we as teachers always tweaking our lessons–even the successful ones??) but I would say this project is a keeper!

Materials to use:

Popsicle sticks, spoons, rubber bands, various sizes of cups, tin cans, toothpicks, duct tape –really anything you can find that you think will work!

Other things you may need:

Cups to stack for the power station, sugar cubes (can be used for harder projectiles), meter sticks, a container for the accuracy station, and tape for starting lines. Use this worksheet packet as well – CrazyCatapults.docx. I adapted this from TryEngineering.org and from Vivify’s site. Both these sites contain great ideas for STEM challenges and activities and you should check them out!

Mystery Powder Investigation

Mystery time! Can you figure out what the four white substances are? This lesson can be used to show properties of difference substances or demonstrate differences between chemical and physical changes. Or it can just be for fun!

 

Lesson introduction:

I introduced this investigation to students after discussing chemical and physical properties of substances. For a “warm-up” I asked the students if they would ever accidentally mistake glue for milk. “Gross!” seemed to be the normal response. However, they easily listed several reasons – color, viscosity, density – it was clear which liquid students could drink. I even showed students what happens when you mix vinegar with both. Again, they were grossed out by the curdling milk.

Powder Investigation Set Up

Before class, I prepared the lab for the students. Containers A, B, C, D were filled with a different white powder. I also included a magnifying glass, beakers of water and vinegar and an eye dropper in their lab baskets. Sheets of foil were ready for them to use as “plates” or testing stations for their powders as well. I do use iodine, because this makes a chemical reaction with one of the powders, but I don’t let any of the students handle it. and we put any iodine mixture in separate spaces.

Materials used

I placed cornstarch in container A, salt in container B, baking soda in container C and sugar in container D. Feel free to use other white substances (safe ones please!), but I chose these four because I had them available in my classroom, and they are “safe” to use. Remember… middle schoolers want to eat everything. I’m not going to use things that might put them in danger! Each substance also has a unique reaction to at least one of the tests that students can choose from. Cornstarch changes the color of iodine, salt has crystal-like particles, baking soda fizzes with vinegar, and sugar tastes sweet!

Time to test!

Students test a powder by mixing vinegar and watching for changes that occur!

I let students choose which tests they would like to do with the substances. This includes mixing the substances with water, vinegar, or iodine, feeling the textures of each, using the magnifying glasses to observe the particles, and of course, the taste test (but I make them wait to do this last so it is not a giveaway!)

It is important to emphasize where students may see chemical changes happening. I ask the students these questions:

Are there bubbles?

Was there a color change?

Did something new form?

Can you get the substances back?

While testing, students fill out a chart like this: MysteryPowders. A “P” is placed in the blank if a physical change occurs and a “C” for any chemical changes.

Mystery Solved!

At the end of the time, I do tell the students what each of the substances were and they are excited whenever they guessed correctly!

Have fun investigating!

 

Density Rainbow – Using Colored Liquids to Explore Density

 

Density can be a tricky topic to teach. Students usually understand the concept of mass. They can feel the difference in something that is more massive (or heavy) than something else. Volume can be shown easily — which one is bigger? What takes up more space? When you put mass and volume together, sometimes students get mixed up. Does heavy always mean dense? Does little mean it will be less dense?

I have a fun activity that addresses some of these possible misconceptions. It uses simple materials and the results turn out beautifully (if students do the lab correctly!).

The set up:

This activity can be used before introducing density as an inquiry activity, or it can be used as a culminating activity. Since my sixth grade students have worked with density here and there, I incorporate the lab after our official density lesson. In the days before, we work on understanding what makes something dense, students practice calculating density and we may even play a few rounds of “Sink or Float.” (This is SO easy for any grade level and students love it! You can either do it as a demonstration, or have small groups do it. Just get a beaker filled with water and random items from the classroom and students must predict whether it will sink or float when dropped in the water!)

Density Rainbow

In the Density Rainbow activity, students find the density of five different liquids and pour them one at a time into a 100mL graduated cylinder. If the students are careful with their pouring, the result is a beautifully layered, colorful cylinder!

Before measuring a liquid, students predict where in the layer it will go. On the top? Bottom? Somewhere in the middle? Because I want to include the math, I make students find the mass and volume (about 15mL) of each liquid, and then calculate the density. Most students see the connection between the numbers they are getting and where the liquid will end up. The higher the density, the lower it will go in the cylinder.

Make sure you tell the students to pour each new liquid carefully! Tilt each cylinder and pour the liquid down the side of the 100mL cylinder SLOWLY! This is especially important with the rubbing alcohol. If students splash, the colors will get mixed and the final result won’t be as pretty.

Here are the liquids I use:

The liquids ready to go!
  • A) Water with green food coloring
  • B) Vegetable oil (no food coloring necessary – it won’t mix well anyway!)
  • C) Blue dish soap (you can use any color of dish soap you would like, but I like the blue best!
  • D) Corn syrup with purple food coloring (this gets very thick and sticky!
  • E) Rubbing alcohol with red food coloring.
I label all the cups so students know what liquid to use when.

Condiment cups are also extremely helpful in this activity. I can prep this lab the day before, pop the lids on all the liquids and not worry about spilling or evaporating. You can find the cups most grocery store in the paper goods aisle. If you have a Gordon Foods nearby, they have huge packs of them too!

The final product!

If you would like to use the handout that I do, here it is: Densityrainbow.doc

Notes and extensions:

Because I have students find the mass, they must first find the mass of the empty graduated cylinder they use to measure with. I am always double checking that they are subtracting the mass of the empty cylinder from the mass of the liquid plus the cylinder. If they don’t do this, their calculated density will be off!

Another extension I do is have the students change the volume and predict if the layers will still be the same. If we used 30 mL of vegetable oil and only 10 mL of water, what will happen? We do this as a group and it leads to the discussion of why adding MORE liquid does not change the density. A few of my quicker students pick up on the fact that when you increase volume, you are also increasing mass, so the density will be the same!

Have fun adding some color to your classroom! If you have any other ways you like to teach density, share them! I love introducing new activities to my classroom repertoire!