Planets (plus a motorcycle)

I completed a pet project today which was meant to broaden the minds of my students. When you live on a small island, it isn't easy to grasp just how large things such as the solar system really are. So I came up with a way to convey the size and the layout of our solar system for our school. This little project would teach science as well as mathematics.

We have a concrete driveway that led to the old school which was torn down several years ago. I recently took a meter stick and carefully measured the entire length of this driveway, from the blacktop of the main road where it connects to the end of the concrete. I found it to be 63 meters long. Within this length, the entire solar system would be represented.

Now I know that many of you, like me, learned when we were young that we have nine planets—Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. However, Neil deGrasse Tyson and others in the International Astronomical Union (IAU) led a movement in 2006 to remove planetary status from Pluto, which is just one of several large icy objects beyond Neptune. Pluto (along with others, including an even larger icy object further out named Eris that was discovered just prior to the IAU decision) has been demoted to a new classification known as dwarf planets.

Thus, I only needed to fit eight planets into the 63 meter length of our driveway. Neptune automatically would be at the end of the driveway, while the sun would be the blacktop of the main road where the concrete driveway begins. Since Neptune is 2.8 billion miles away, we needed to divide 2800 into 63 to determine that every 2.25 centimeters equaled one million miles. By doing these calculations, the students got to see how mathematics can be used in real life situations. [Yes, I mixed miles with meters, since we have a nice meter stick, but it just wasn't essential to do this exercise entirely in metric numbers. Besides, much of life in Dominica involves a mix of English and metric systems.]

By researching the distance the other planets are from the sun, and then multiplying each million by 2.25, we could determine where they would be placed along the length of the driveway. Today, the older students helped me during lunch to lay out the planetary locations using the meter stick and chalk on the driveway. Then, we got out some paint, and permanently painted these locations on the driveway (as shown above and below this paragraph). The “artist” in me wanted to do all the painting, but I realized it was important that the students feel some ownership for this project, so I let them do nearly all of the painting.

Seeing how close the four inner planets are to each other (as well as to the sun) gives the students a better feel for the great distances to the outer planets. Mercury is about 80 centimeters away from the sun, while Mars is about 3.2 meters away. Earth is almost 2.1 meters from the sun in our model, but in reality the Earth is 93 million miles from the sun. [By the way, to keep things simple, I didn't try to represent the relative sizes of the planets—it was enough merely to demonstrate the distances between their orbits. Besides, the inner planets would just be tiny dots on this scale.]

After we were done, the students each picked a planetary orbital distance to stand beside, and their teacher stood way in the back where Neptune is represented. I then took the picture shown below from across the road. Their teacher is hard to see, but she is there wearing a light blue blouse. [Note that the student on Venus stepped back to look towards his teacher when I snapped this picture, inadvertently making him too close to Mercury and too far from Earth.]

I'm glad to have completed this project for our school. It helped me to connect with my days working at NASA, and hopefully it helps to expand the minds of my students.

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After school was over, I had one more little project today. One of our younger children recently got a bike for his birthday. I decided to show him how he could turn his bicycle into a “motorcycle.”

When I was a kid, sometimes we would affix cardboard playing cards to our bicycle fender struts using a clothespin. The card would flip through the spokes as the wheel rotated, providing a motorcycle sound as we rode along. I decided to pass along this trick to the children here.

The picture below shows two of the kids enjoying the new sound effect. Note that I had turned the bicycle upside down to make it easier to work on. Without a convenient fender strut, I wasn't sure how I was going to affix the playing card. However, the kickstand (mounted on the rear axle) was thin enough to allow a clothespin to hold the card.

It was a trip down memory lane for me to hear that fluttering sound again! It was even better to see the smiles it put on the childrens' faces! They loved it!