Category Archives: Science Experiments

College Students & Screaming Balloons

I love to watch actual students doing actual experiments, and my college students and their screaming balloons turned an ordinary writing lab into a writing AND science lab!

Starting at the Stonegate Arts and Education Center in Bedford, Indiana, my Ivy Tech students and I ended our writing lab by discussing how writers sometimes have to describe something in an unusual way.  Mention was made of the South African vuvuzela of soccer World Cup infamy, and so my aspiring writers created this sound with balloons and hex nuts.

Melissa and Alisha with their screaming balloons!
Melissa and Alisha with their screaming balloons!
Kitch and his screaming balloon!
Kitch and his screaming balloon!

Incidentally, the Stonegate Arts & Education Center is an Ingress portal, in case you might be interested in that.  And I hope you are.

Stonegate Arts & Education Center in Bedford, Indiana - Ingress Portal!
Stonegate Arts & Education Center in Bedford, Indiana – Ingress Portal!

That was all on Wednesday afternoon. Thursday night my students at Ivy Tech at Springs Valley Learning Center in French Lick, Indiana had this same lesson.  Different town, different students, same concept.  Similar reactions.  Even the facial expressions were similar!

Pamela, Kendra, Raven, Chelsea, and Andre having fun with their Screaming Balloons in French Lick!
Pamela, Kendra, Raven, Chelsea, and Andre having fun with their Screaming Balloons in French Lick!

It’s not just little kids who love science, you know.  College students and adults love science, too!

Steve Spangler warned me to bring earplugs to class this past week.  I should have taken his advice!

 

Holiday Science: Gravy

What’s so scientific about your holiday gravy?  Isn’t gravy just, well, food?  Food we put on mashed potatoes and turkey at Thanksgiving and Christmas and Sunday and, well, pretty much any time?   How could gravy have anything to do with science?

Yummy! But science?  How in the world. . . .
Yummy! But science? How in the world. . . .

Here’s the thing, drooling holiday turkey & gravy lovers:  gravy-making is all about the science of starch.

Starch?  That white powdery stuff Great-Grandma used to make her handkerchiefs and your Great-Grandpa’s boxers smooth and stiff?

Yep.  Exactly.  Only in the kitchen, we use white powdery stuff made especially for use in food.  Otherwise, it’s the same stuff.

Starch is plant-based, and many people use wheat or corn-based starches to make gravy.  I like to use corn starch*, as flour (wheat-based starch, no joke!) adds its own flavor to gravy whereas corn starch does not.  Both, however, require some fancy whisking to get all the lumps out!  (If you’ve ever had to choke down lumpy gravy, you’ll appreciate the extra effort put into smooth gravy!)

A kitchen whisk makes stirring lumps out of gravy a lot easier and quicker!
A kitchen whisk makes stirring lumps out of gravy a lot easier and quicker!

What is starch, exactly?  Interesting question!  Starch is a complex carbohydrate.  To put it more simply, starch is a fancy chain of sugars – fancy, because while sugar dissolves completely in liquid, starches absorb the liquid, rather than disappearing completely in it.

If you added a heaping tablespoon of sugar – white or brown – to your skillet of hot turkey fat, it would simply disappear, completely absorbed by the liquid.  But if you added a heaping tablespoon of cornstarch or flour to that same skillet, it would start bonding with the fat and the entire contents would start to “gel.”  Add a little salt and some milk to your skillet, keep stirring, and in a few minutes, you’ll have delicious gravy, table-ready to pour right onto your mashed potatoes and turkey slices.  Without the addition of milk, your gravy would be too stiff to ladle out!

If you use flour as your starch, your gravy will be a little “stickier” than gravy made with corn starch.  Many people prefer that, and many people do not.  Your call.  If you have a gluten allergy, use corn starch – flour contains gluten.

Take a quick scientific peek at what you’re adding to your gravy:

Simple starch molecule
Simple starch molecule

You see?  I TOLD you gravy was scientific!

Especially for you cooks, here’s a simple recipe for holiday (and any other day) gravy:

In a large skillet, heat (on low) 1 cup of turkey drippings (or ham drippings, or bacon drippings, or butter), stirring constantly.  Sprinkle one heaping tablespoon of corn starch onto the drippings, still stirring constantly.  When the mixture begins to bubble, SLOWLY add milk (or water if you don’t want your gravy as rich) and still stirring constantly.  Switch out your spoon for a whisk, and begin slowly whisking the mixture.  It will start to firm up very quickly.  When it’s the right degree of firm to your taste, remove from heat and pour into a gravy boat or bowl.  Take it to the table and start eating.  Gravy should be served and eaten immediately, so it’s probably going to be the last thing set on the table before everyone dives in.  If gravy has to sit and wait, the consistency changes.  That’s scientific, too.  Look it up.

Make a big batch; gravy freezes nicely, and there’s something about turkey gravy in the spring. . . .

Don’t think it’s just wheat and corn that contain starch.  Loads of vegetables, legumes, and grains are starchy.  Potatoes,  pumpkin, sweet potatoes,  all kinds of beans, peas, rice, and tons of other foods are starchy.   Don’t try to make gravy with all of them, though.

*Yes, indeed, the same corn starch we use for our non-Newtonian liquids!  In fact, gravy IS a non-Newtonian liquid!

How to Study Density with Popcorn

by Christy McGuire, Contributor

Thanksgiving is almost here! You can use one of the original foods from the first Thanksgiving to discuss density with your students. Popcorn is fascinating because it changes so drastically during the cooking process. The color, shape and texture of a popped kernel are all different than those of an unpopped kernel. If you can spare the day before Thanksgiving break, this simple density experiment would be a great way to practice their inquiry skills, and a great excuse to have a treat in class!

How to Study Seeds with Popcorn/How to Combine Thanksgiving and Science in your Elementary Classroom

If your students have already covered density, this is a great time to practice doing a full exploration complete with a written report. You might simply give them access to the relevant materials and set them loose with this challenge:

Find how density changes for popped verses upopped corn. Check the results of your experiment and write a description of your findings, including an error analysis.

If density is a new concept, or if your students are struggling to get the hang of the scientific method, you can help them figure out the procedure. Make them do as much of the thinking as possible though! Science is more fun for the engineer making the decisions than for the technician doing as he is told.

Leading questions to help students develop their procedures

How do we calculate density? (mass per volume)

What measurements will we need to take in order to find density? (mass and volume)

How do we measure mass? How do we measure volume? (balance, and appropriate beakers)

How are we changing the popcorn? (popping method)

The Science of Popcorn

Hints for a successful experiment

You can expect your popcorn to increase in volume by about 16X.

To  pop the corn over heat, put a couple of tablespoons of oil in the pot or beaker, add corn and heat over medium heat.

If you are using a microwave, you can measure the volume of the popcorn in a bag of microwave popcorn and assume the same volume is in a second bag of popcorn that you pop before class.

Increase accuracy by repeating with varying quantities of popcorn, or by combining data from multiple lab groups.

Science of Popcorn

Data Analysis

If you wish, you can have your students graph mass a function of volume for various amounts of unpopped corn, then do another graph for the popped corn. The slope of these graphs will be the density of the popcorn.

You can also ask your students to compute density algebraically, then graph density as a function of popped or unpopped.

Requiring students to analyze the accuracy of their results could provide some very interesting feedback. Lab groups could compare results with the rest of the class. They can also compare the initial and final masses and try to defend any changes that they find. My experience is that the mass of the popcorn actually increases during this experiment. Don’t tell your students! See what they can come up with to justify their own answers. Factors that they may want to consider include the mass and volume of the oil used to cook the kernels and the humidity on the day of the experiment.

No matter what your students’ level, this experiment can be adjusted to provide a challenging, and interesting exercise. I hope you will enjoy. Happy Thanksgiving!

 

Christy McGuire is a trained physics teacher who loves developing new ways for students to engage with science.  While taking a break from the high school classroom, Christy rediscovered that young children are tons of fun, and can learn powerful science and math too.  Now she is attempting to cross the excitement of early childhood style learning with serious STEM study to benefit students on both ends of the learning process.    Find activities and reflections on STEM learning on her blog: www.ThrivingSTEM.com.

How to Use Popcorn to Teach Rates

by Christy McGuire, Contributor

This time of year, students’ minds are starting to drift to the upcoming Thanksgiving Holidays. Why not use popcorn to channel a little of that excitement into your classroom? Use popcorn to teach graphing, rate, and slope. Let your students eat your props, and you will quickly be one of the coolest teachers to ever discuss rates.Here is how to use popcorn to teach rates.

How to Study Seeds with Popcorn/How to Combine Thanksgiving and Science in your Elementary Classroom

The Slow Approach

Materials:

  • Popcorn
  • Paper towel
  • Small plastic bag
  • Cups of Potting Soil
  • Ruler

Last week I gave some ideas for teaching younger students about seeds using popcorn.  Corn germinates quickly and grows quickly too, which makes it a great plant to measure over a period of time. You can get a meaningful graph by measuring every day or so.

 

  1. Start having students set up corn to germinate in the window. You can expect germination to take about three days.
  2. Then plant it in a pot with soil.
  3. Have your students measure the height of the plants every day or every two days between now and Thanksgiving, and record your findings on a labeled data chart.
  4. On the last class before Thanksgiving break, you can have them graph their findings. You may want to remind them that time is the independent variable, and thus belongs on the x (across the page) axis. Height is the dependent variable and thus belongs on the y (vertical) axis.

How to Use Popcorn to Teach Rates

The Fast Approach

Materials:

  • Popcorn
  • Stop watch
  • Oil
  • Cooking Pot
  • Heat Source

(You can also use a bag of popcorn and a microwave)

Have your students get set with lined paper and their pencils. Tell them that during each twenty-second interval, they are to make a mark for each pop that they hear.
When you call time, move to the next line and make a mark for each pop. They will repeat until all the corn is popped.

  1. Put a couple tablespoons of oil in the cooking pot and about a quarter cup of popcorn. Cook on medium heat with the lid covering the pot.
  2. When you are finished, pop some more corn, and let your students enjoy while they make their data charts and graphs. Time is again the independent variable and belongs on the x (horizontal) axis.
  3. If there is interest, try repeating for differing amounts of popcorn and think about how the amounts affect your data.
How to Use Popcorn to Teach Rates
Analyzing the Data for Either Approach (or Both!)

Depending on where you are in your curriculum, there are a few different directions you can take your class after completing their graphs.

If you do both of these projects, ask students to write a paragraph comparing and contrasting the graphs.

Or, You can have your students draw tangent lines near the beginning and end of the curve. Tell them to find the slope of each and write an explanation of why the slopes are different.

Or, ask your students to add best fit lines to the graph and calculate their slopes. Students can write a paragraph in which they compare and contrast the results of the best fit line to those of the tangent line and give an opinion on which is more useful.

Or, tell students to add a third tangent line in the middle, and find that slope. Then, graph the slopes verses time.   Ask students to write a paragraph explain the meaning of this new slope.

Put popcorn on the shopping list and plan to have some fun in your class this week.

 

Christy McGuire is a trained physics teacher who loves developing new ways for students to engage with science.  While taking a break from the high school classroom, Christy rediscovered that young children are tons of fun, and can learn powerful science and math too.  Now she is attempting to cross the excitement of early childhood style learning with serious STEM study to benefit students on both ends of the learning process.    Find activities and reflections on STEM learning on her blog: www.ThrivingSTEM.com.

How to Combine Thanksgiving and Science in your Elementary Classroom

How to Study Seeds with Popcorn
by Christy McGuire, Contributor

Students’ minds are turning to the holidays. You can harness some of that excitement by including some holiday-themed activities in your classroom.

How to Study Seeds with Popcorn/How to Combine Thanksgiving and Science in your Elementary Classroom

There are many great learning activities that follow holiday themes. Here are two activities that combine Thanksgiving and science.

We love studying (eating!) popcorn seeds year round at our house.

Here are two activities that will help your students understand the parts and functions of a seed.

Used together you have a hands-on opportunity to discuss all the parts of a seed and their functions, and the general characteristics of a seed as well.

A key to making these activities irresistible. Is to use the same popcorn for all parts of the demonstration. If possible, pop the corn in front of your students.

Activity one : Grow a Popcorn Plant

This classic demonstration is more intriguing done with popcorn.

Materials:  

  • unpopped corn
  • baggies
  • wet paper towels
  • tape
  • windows

How to Study Seeds with Popcorn/How to Combine Thanksgiving and Science in your Elementary Classroom

Steps: 

1. Let your students place three or so kernels in the baggy with a wet napkin.

2. Write their names on the baggies and tape them to the window.

Corn germinates quickly, so if you set this demonstration up on Friday, chances are good that by Monday you will have something fun to look at.

Some questions to ask the day that the seeds germinate:

“Where does the energy for the little plant to grow come from?”

“Why do all of our plants look similar to each other?”

“Why is corn planted in the spring and not in the fall?”

 

Activity two: Seed coat observation

This activity was actually developed by my children. Playing in water is always a hit!

For maximum excitement, pull this activity out on the day your students find the germinated popcorn seeds as a kind of extension.

Materials:  

  • unpopped corn
  • a method for popping the corn
  • water in small dishes

Steps: 

1. Hand out popped and unpopped corn.

2. Tell your students to draw pictures and write descriptions in their science journals.

3. Have your students place unpopped corn in a dish of water.

How to Study Seeds with Popcorn/How to Combine Thanksgiving and Science in your Elementary Classroom

4. Pop some corn.

5. Have your students place it in a second dish of water.

6. Wait for five minutes or so. While you are waiting, discuss the seeds.

“What is the difference between these two types of popcorn?”

“What is the yellow shiny thing on the outside of the unpopped corn?”

“Why do you think seed coats are important?”

How to Study Seeds with Popcorn/How to Combine Thanksgiving and Science in your Elementary Classroom

7. When the five minutes has passed, encourage your students to make observations and record them by drawing pictures and  writing descriptions. First have them just look at the seeds, then allow them to touch the seeds as well.

Some questions to ask in summary:

What about the seeds changed?”

“What stayed the same?”

“Why do you think the seed coat is important?”

Finally after all that work, be sure to EAT some popcorn.   (Check for corn allergies first.) Nothing is better than eating your own experiment! Oh, and while you are munching, “What is it about seeds that makes them good to eat?”

 

 

Christy McGuire is a trained physics teacher who loves developing new ways for students to engage with science.  While taking a break from the high school classroom, Christy rediscovered that young children are tons of fun, and can learn powerful science and math too.  Now she is attempting to cross the excitement of early childhood style learning with serious STEM study to benefit students on both ends of the learning process.    Find activities and reflections on STEM learning on her blog: www.ThrivingSTEM.com.