The Speed of a Rotating Cookie

August 29th, 2016


Today we are baking a gigantic cookie, and then we will spin it! We are attempting to determine the speed of a rotating cookie, and I will compare it to a merry-go-round.

First you need to go into your kitchen and bake a huge chocolate chip cookie.

baking-cookiesThis post contains affiliate links. I was compensated for my work in writing this post.

You can use your favorite cookie dough recipe. My daughter Rachel tells you how much of each ingredient she used to make her cookie:

This fun experiment is from Christian Kids Explore Physics by Bright Ideas Press, In the chapter on motion, the book describes how to figure out the speed of a merry-go-round. First you need to determine the circumference of the merry-go-round.

C = 2π r

The radius of the merry-go-round is 5 feet.

5 times 2 times 3.14 equals 31.4 feet. So the distance around the merry-go-round is 31.4 feet. That means every time Rachel goes around, she travels 31.4 feet.

Now we need to determine how fast the merry-go-round is going. My son pushed Rachel around as hard as he could while my other son timed 15 seconds. I counted how many times Rachel went around in 15 seconds. The answer was almost 4 times–3.75 times is more accurate, as you can see if you watched the video. 3.75 times 4 equals 15 revolutions per minute. (A minute has 4 segments of 15 seconds.)

To determine how many feet Rachel traveled in one minute while riding the merry-go-round, multiply the circumference by the speed. She traveled 471 feet per minute!


In the video I show you how to determine the speed of your rotating cookie at home, depending on how big it is and how fast you spin it. Who knew physics could be so fun and delicious!

Rembrandt Art Projects for Kids

August 25th, 2016

Rembrandt-art-projects-for-kidsThis post contains affiliate links. I was given access to the class to blog about it.

We are on the second lesson of Mixing with the Masters, and this week we are doing some beautiful Rembrandt art projects. Rembrandt is my favorite painter. I’ve used his artwork to teach my children Bible stories, since he painted so many biblical scenes:

Charcoal & Gesso Portrait


The first art project is a charcoal and gesso portrait of Rembrandt. This artwork is better for older students, since the shading on the face is crazy. Your kids need to be prepared for the first layer to look unfinished. This is a three-day art project.

Before you start, print out the sketch (template) of Rembrandt that Alisha (the art instructor) provides. I also printed the black and white portrait and the gray scale. I enjoyed Alisha’s teaching about the gray scale, and my children noticed different shades and tried to match the gray scale shades to what they were painting with gesso.


Coloring on the back of the template with a charcoal pencil will enable you to transfer the sketch to the paper without your children having to draw the original. You just use a mechanical pencil without lead to trace the sketch onto the watercolor paper.

Let the first layer of gesso dry, and the next day you can darken or lighten your drawing in different places. Alisha gives instructions on how to do this in the demonstration video for this project.


The gesso portraits came out way better than I thought they would! I was expecting them to look like a Picasso, based on how crazy they looked on the first day when we shaded the faces. It was almost as if someone splatted Rembrandt with a chocolate pie, except in black and white.

The most fun part of this project was painting the gesso on top of the charcoal and having the shades mix while you paint. We had never used gesso before!

Ink Pen Sketching


All you need for this ink pen sketching is a pen and paper. We used Alisha’s template for the shape of the dog so that we could focus on the cross-hatching technique that Rembrandt used on his etchings. The puppies came out cute.

The Mill: Mixed Media


We started this mixed media project with a black canvas. (I prepared the canvas by giving it two coats of black paint before we began the project.) I also bought four different scrapbooking papers that had cool patterns in brown. We used that for the cliff and windmill, using the template that Alisha provides in her class.

Alisha’s mill looked a lot more like the original painting by Rembrandt, with a light tan sky and dark brown earth. She talked about the use of chiaroscuro, which is a technique that uses light and dark for effect. We just reversed the effect by painting a dark sky blue and having the mill be a lighter tan.


If you would like to take this class, go get it here: Mixing with the Masters. We are really enjoying these art projects!


Turning Potential into Kinetic Energy

August 22nd, 2016


In today’s experiment, we will be turning potential into kinetic energy as we hold various objects above a bucket of water and release them to see how far they splash.

Sounds fun, doesn’t it?

You will want to do this experiment outside on a sunny day. The person dropping the objects needs to be willing to get wet, especially when the person releases the heavier objects like the banana and the can of baked beans!

Turning Potential into Kinetic Energy (The Experiment)

Step 1: Gather supplies. You will need a large tub, a hose, a ruler, and various objects to drop into the water. We used a marshmallow, a grape, a nut, a quarter, a pine cone, a banana, and a can of baked beans.

splashing-experimentThis post contains affiliate links. I was compensated for my work in writing this post.

Step 2: Fill the tub with water and have someone hold a ruler on the side of the tub. Print out the chart on page 143 of Christian Kids Explore Physics by Bright Ideas Press, and clip it to a clipboard. Record your findings on the chart, or you can just call out how many inches the water splashed upwards.


Step 3: Drop each object and watch how far the water splashes. The objects with more mass have more potential energy. When an object is held above the water, there is potential energy in the object. Potential energy is converted into kinetic energy as soon as you release the object because it is now moving.

Let me describe it another way: A log of wood has potential energy. It’s just sitting there and doesn’t look like it has energy, but as soon as you light it on fire, the potential energy is converted into kinetic energy.

Energy will be released if something happens to an object with potential energy. As long as an object just sits there, it’s only potential. When movement or chemical change occurs, you now have kinetic energy.

Video of the Splashing Experiment:

Take a look at how far each of our objects splashed:

Hope you enjoyed our fun experiment!

Leonardo da Vinci Art Projects for Kids

August 19th, 2016


This post contains affiliate links. I was given access to the class to blog about it, which I was very glad to do.

I’ve been wanting my kids to get proper art instruction for years now, especially for my oldest son who is a natural artist. So when I found this Mixing with the Masters art class, I was eager to join. And I wasn’t disappointed! There are six great artists that will be covered in this online class, with three art projects for each artist. You can do them at your own pace and can spread them out over an entire homeschool year if you want, taking one artist per month instead of one per week.


The first artist was Leonardo da Vinci. There are three substantial tutorial videos, along with an introductory and concluding video, along with a lot of other goodies, like printables and links to other sites that are about Leonardo da Vinci.

Mona Lisa Collage: Torn Paper on Canvas


The first art project is mixed media. Alisha (the instructor) gives specific instructions on how to do decoupage on canvas with torn paper, creating a gorgeous Mona Lisa! My kids’ masterpieces looked like stained glass windows! We broke the project down into three days: one for the torn papers, so they could dry; one for paint, so that it could dry; and one for the detail work at the end.


You’re probably laughing if you looked closely at the blue Mona Lisa. Yes, my 16-year-old son used twine for her hair, which makes her look like she has dreadlocks. Oh, there’s another cool thing about this class–besides self-expression. I’m using this as high school art credit.

If you would like to integrate language arts into your study of the Mona Lisa, you can write a poem about her. Here is a hysterical poem written by my 11-year-old son:

Leonardo da Vinci Charcoal Wing


The second art project was charcoal on tan sketching paper. (You can stain some computer paper with tea if you don’t have any tan paper, or use tan card stock paper or construction paper.) We also used a blending stump, which we’ve never used before, and a white charcoal pencil for highlighting. My children watched the video demonstration and did each step. Their wings came out great! And my artist son gained new skills in shading and in using a medium he had never used before.


After the video demonstration, when my children were finished with their Leonardo da Vinci wings, I grabbed some tan paper, looked into a mirror, and I drew a self portrait:


I think it came out great, considering I’m not an artist!

Last Supper Fresco


The third project was a Last Supper fresco. My kids were familiar with the famous painting because we made the Last Supper in LEGO last year. Ha! My son did a great job positioning Jesus and the disciples in the exact same postures as the famous painting!

For the Last Supper fresco, Alisha did a close-up of some pewter dishes on the table with the robe of Jesus in the background. We decided to do a sunset and an etching of the Last Supper:

  • Day 1: We poured Plaster of Paris into a lid of a shoe box.
  • Day 2: The kids painted a sunset, spraying the dry plaster with water as they worked, which melded the colors together.
  • Day 3: We etched the Last Supper with a mechanical pencil with no lead. It showed the Plaster of Paris underneath.

We thoroughly enjoyed this class and gained new skills. If you can’t afford to buy the whole class (the set of 6), you can always buy this class separately if you are studying the Renaissance in history. Who could study the Renaissance without doing art?


Changing the Coefficient of Friction

August 15th, 2016


Today we are doing an experiment about changing the coefficient of friction. We will be swooshing a penny and a book across an unpolished table. Then we will polish the table and try it again.

Friction is resistance that keeps an object from moving forward. As you can see in the video, our coffee table has seen better days–it is battered and has lots of tiny grooves and dents. This provides a surface that is full of friction to cause a penny or book to slow down while being slid across a table.

How to do the friction experiment:

sliding-pennyThis post contains affiliate links. I was compensated for my work in writing this post.

This is how we conducted this friction experiment from Christian Kids Explore Physics by Bright Ideas Press:

Step 1: We slid a penny and a book across an unpolished table. We noticed that the penny got stuck as it didn’t want to slide across a table full of nicks and dings.

Step 2: We polished the table with furniture polish. Using a soft rag worked better than using a paper towel, as far as shining the table. The reason the table never looked visibly shiny is that there was no varnish left on the poor coffee table. Even then, the table became more slippery when polished.


Step 3: We slid the penny and the book across the polished table. This time we noticed that the penny had less friction as it slid across because there were fewer obstacles slowing it down.

My kids went next door to slide the penny on the neighbor’s waxed wooden floor. The penny slid around with way more speed! Even the neighbor’s dog had trouble walking on such a frictionless surface!

Then my husband polished one side of the coffee table and not the other, and there was a visible difference in speed when he flicked two wooden coins across the table. The polished side went noticeably faster and flew off the table!

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