Friday, December 12, 2008

Terrible Science Experiments

(Updated to fix the time stamp)

I picked up the book "Astronomy for Every Kid: 101 Easy Experiments that Really Work" by Janice VanCleave at the latest library book sale. Janice VanCleave is a name that abounds in the science section of my library. She is a prolific writer of experiment books. I have not read her other books, but it seems that in getting to 101 experiments for astronomy, she included a number of poor choices. I have a version of the book copyrighted in 1991.

Some of the experiments in this book are good. Some are OK. It is for this reason that I felt compelled to add my two cents for which experiments should be skipped.


Examples:


8. Thick
In this experiment, the child is supposed to learn why it's hard to look through Venus' atmosphere. So the author has the child try to look at a flashlight beam through waxed paper. Apparently this is supposed to emulate the way that more carbon dioxide in Venus' atmosphere bounce the light around more and make it difficult to see the surface. An experiment with no value whatsoever.

10. In Place
This is the worst one. This experiment is supposed to demonstrate the center point of the Earth-Moon gravitation system, the barycenter. Use a pin to secure the center of the circle to the eraser of a pencil with a bit of clay on the tip to represent the moon. Put a black dot on the pencil half an inch in from the edge of the circle. Now rotate the circle and notice the dot stays about a half inch from the edge of the circle. What you just demonstrated was that you are good at cutting out circles, finding their center, and drawing dots in from the edge.

14. Sun Prints
Use developing paper to make a print. This is done by taking specially treated paper that changes color when left in the sun. Parts of the paper that are not exposed will not change color. Hold onto your hats--this is supposed to demonstrate some ideas about why Jupiter has vary colored clouds. "Scientists think that the colors may come from chemicals in the clouds because of Jupiter's lightning or that the Sun changes the colors as it did the special light-sensitive paper." It's a bad experiment mostly because it relies on 'magical' paper (to the kids, anyway) and has a very wishy-washy theory to support that is probably wrong. It may be due to the age of the book.

17. Hot
Feeling warmth after vigorously rubbing your hands together is supposed to show that conservation of energy is why atoms bumping together in Jupiter's dense atmosphere do not cause a change in temperature at the surface of the planet. So a kid is supposed to generate heat to understand why heat is not generated.

27. How Far
To show how Pluto can sometimes be inside Neptune's orbit, draw any two ellipses where part of one ellipse is inside the other. You are not even constrained by one of the foci (you know, the Sun) being the same for each orbit.


30. Elliptical
The experiment has kids tracking the trajectory of a marble as it shoots from a straw and then falls according to gravity. The experiment is fine, but the title is completely mistaken. The experiment is designed to show how planets move in curved paths, ellipses, because they are captured by gravity. Though I may be picky, the path traced by a projectile with constant horizontal velocity under the acceleration of gravity is a parabola. They could have found a less inaccurate name.

40. Waves
Put a magnet under a piece of paper and sprinkle iron filings on top of the paper. When the magnet is moved the iron filings move with the magnet. "Purpose: To simulate the presence of planets with magnetic fields." Perhaps there was a type-o? Maybe the purpose is to show what a magnetic field looks like?

46. Sky Path
Use a piece of paper and a glass bowl and a whole day to demonstrate that the Sun moves from East to West across the sky. This is just time consuming. The point is that the Sun just looks like it's moving--it's really us.

48. Moving Target
Make a pendulum using a washer and string. Set it in motion and then try to hit the washer with a wadded up piece of paper. It is hard. You need to aim for where the washer will be after the paper has left your hand and had time to travel. It is like getting to the Moon. Except NASA had the most advanced computers at the time, the math and laws of Isaac Newton, and some of the best scientists and engineers working on the project. The point is not that the experiment is bad, it is just that the experiment will make the kid frustrated. I would not want any kid to get the idea that NASA just had good luck--which is what the kid would need in order to hit the washer. They could hit the washer with great equipment, precise timing, the fundamental equations of motion, and superb calculating ability. Which is not to diminish the great accomplishment of the moon landing--but to point out it was not luck and we had a lot more on our side than the poor kid who will probably not hit the washer.


I only went trough the first 51 of the 101 so far. I started to ignore other experiments that included demonstrations where the observed behavior kind of matches the observed behavior 'out there' without actually using any of the same causes of the real behavior. I also tried to ignore the many experiments that show the opposite of the point actually being made--like the marble rolling in the funnel falls to the bottom due to friction slowing it's forward velocity and allowing gravity to pull it down and satellites stay in orbit because there is no friction.

(Updated to fix the time stamp)

12 comments:

christinemm said...

Fantastic post. I appreciate the time you took to share your thoughts with us.

In November I culled my science experiment books as to be honest I somehow amassed way too many and (confession here) had used none.

Van Cleve is applauded by school teachers as well as homeschoolers.

Often we don't do experiments of that type because my kids seem to already accept or understand something they have either seen in real life (Earth moves not the sun) or we just don't need to do those types of activities to try to prove the point.

The experiments built into Real Science 4 Kids curriculum we are using this year seem to be not a waste of time. If you have an opinion on that curriculum perhaps you could blog it in the future?

Thanks Kim.

christinemm said...

Kim please consider posting this to the Carnival of Homeschooling. It is perfect submission.

Visit whyhomeschool.blogspot.com to link through to submit.

Deadline is 9pm EST Mondays. You can also submit it next week or any other time in the future too.

Have a great weekend.

Kim said...

Thanks, Christine. I took your suggestion and submitted the post.

I wasn't doing nearly enough science. That was part of the reason I started the course. The other part was to try out a specific order of presentation.

I took a look at the chemistry section of Real Science for Kids. It is certainly a comprehensive curriculum. I didn't notice any experiments so much as projects or crafts. It matches how the curricula are presented in the standard school curriculum, though presented to much younger kids. The chemistry begins right away with atom structure and moves right into bonds--even bringing up ionic and covalent bonds and telling the kids they don't have to worry about understanding it. I find that irksome. That is one of the reasons I'm trying to find a more logical presentation.

KarenDV said...

Thank you! Demonstrations or examples are not the same as experiments. This is one of my biggest gripes with most homeschool science curricula.

To her credit, though, Van Cleave does offer many better experiments in some of her books geared toward older kids (interspersed with clunkers). We are successfully using parts of her A+ Projects in Biology to supplement our 5th-grade life science work.

My rule of thumb is, if you wouldn't write a lab report about it with a HYPOTHESIS and an INVESTIGATION (i.e., if you know what will happen before you even do anything), it isn't worth doing.

motherbynature said...

Love this post! Thanks so much... any chance you'll do more like this? ;)

I was actually just considering some of her science experiment books the other day, seeing them at HomeschoolClassifieds but not knowing anything about them. Now I think I'll pass. You just saved me!

Sebastian said...

Very nice analysis of the "experiments." This encourages me to make sure I use a critical eye on our science books.

christinethecurious said...

Have you looked into the books by Bernie Zubrowski? They are good for middle and Jr High. They are unit study like, starting from an phenomena and tracking it through engineering, algebra, art, history, and the physical sciences. The book on shadows, then mirror explained light rays better to me than the physics class I took in High School, but they you always do learn more when you teach.

You may need to check your library, they are being re-published at the moment.

-Christine

MTheads said...

Not being a scientist kind of person, I'd bought into the idea that kids had to do experiments in order to learn science. But over the years, I have come to hate experiments. I've also come to realize that kids need to know something for experiments to make any sense, so we're holding off until...I'm not sure we'll ever do experiments. I'm focusing on math and scientific theory instead.

Kim said...

It is very true that experiments without context are pointless. A pet peeve I had with my previous private school was having a science fair in first grade. They taught the kids nothing and then expected the kids to jump into a fair project. What was truly annoying was how much the parents of the kids did. The parents chose the projects and helped immensely. It was a real shame when the kids could rattle off what they had memorized without understanding it. And the parents were convinced the kids understood it.

I do believe that experiments are important and necessary. Doing well designed experiments can teach a child what good experiments entail. The experiments can often show irrefutable proof that a counter-intuitive result is correct (like heavy things and light things fall at the same rate). Experiments teach proper lab technique--a must for anyone that might go into a technical field or who even wants to be able to follow a recipe properly.

Theory is primary and I whole-heartedly support doing worthwhile experiments that demonstrate the theory and allow the kids to practice and learn application of the theory.

Kim said...

I am not familiar with Bernie Zubrowski. I did a quick search and found his work on Amazon. He has a lot of books each with a different scientific topic. His books seem to go from less complicated to more complicated. The later experiments seem to build on the earlier experiments. That makes a lot of sense.

All of the ones I clicked on were out of print, so I'll check the library next time I go.

christinemm said...

Do you think that perhaps it is a complete waste of time to do experiments on the topic of astronomy with our children?

Perhaps learning by reading textual information, looking at photographic images or drawings, watching video documentaries is okay?

Next notch would be peering through a telescope with some guidance of someone who knows what they are looking at?

Another notch of goodness is a visit to a really good planetarium?

Best option not available to many but is there for those students who take your DH's classes is for young children and tweens and teens to take a class with someone who really knows what they are talking about and to hear other and different info in lecture format and have the benefit of a live knowledgeable person who can answer their questions?

Kim said...

That is a great comment, Christine. It is true that astronomy may not lend itself particularly well to experiment, given that we are talking about 'cosmic scale' stuff.

Astronomy itself began with pure observation. The ancients knew that the stars were fixed, with the exception of the 'wanderers', the planets, incuding the sun and the moon. They named clusters of stars and navigated by them. Because they moved as one across the sky, rotating around the North star, Anaximander believed they lay on a crystal sphere. Anaximander was the first to posit a curved surface of the Earth through the observations the stars seem to move lower in the sky as one traveled north. The ancients were able to discern much about the Earth with their astute observations.

Their knowledge of geometry helped immensely, too. Aristarchus was able to use geometry to prove the moon was smaller than the Earth and approximate its distance based on the diameter of the Earth. He also figured out that the sun was even larger than the Earth and more distant. These clever conclusions allowed him to posit that the Earth moved about the Sun, which was quickly dismissed for poor philosophical reasons (it went against the religion of the day) and because they could not fathom the immense distance of the stars. The ancients knew long before Magellan sailed around the world that the Earth was round based on observations and their knowledge of geometry.

When Lippershey invented the telescope and Galileo refined it and turned it toward the heavens, he discovered many new things. Galileo's telescope revealed mountains and craters on the previously-thought-to-be perfect sphere of the moon and spots on the sun. Then Galileo discovered four satellites orbiting Jupiter, proving that not everything orbited the Earth, and that the planet Venus had phases, which could only occur if it orbited the Sun. The telescope also showed other things like nebula and double stars.

It is logical to begin a scientific inquiry into astronomy the same way. Not only is it logical, it's a perfect way to show kids the evidence underlying our current knowledge. It is also a great technique for showing kids scientific thinking.

That is a great start. That can get the students as far as Copernicus. Galileo, though, revolutionalized scientific thought. His experiments and applying mathematics to motion paved the way for Isaac Newton's laws of universal gravitation. So I would say that experiments related to gravity are certainly in the purview of astronomy. And theories of light, from ancient times and through Newton's experiments, should certainly be included as part of astronomy. After all, most of what we know of the stars comes down to electro-magnetic radiation--only part of which is visible light. Demonstrations or experiments that proved Earth's atmosphere is finite helped to define 'here' vs 'out there'. Experiments dealing with energy help. Experiments that helped us learn about the atom and nuclear degradation would be important as well. Astronomy also includes a lot of chemistry with spectography playing a big part. Only some of these would be appropriate at elementary level, with more becoming appropriate as the child gets older. Of course some experiments are read about instead of performed--unless you decide to become an physicist.

I actually have a bit of a problem with my husband's class that most other people would not share. Hubby's class is a survey course of astronomy. It is jam-packed with a full overview of astronomy from the solar system to the birth and death of stars and galaxies. It is an overwhelming amount of information, and due to the nature of the course, once you start talking about the birth and death of stars, you're in some pretty serious territory. I think it goes straight over some kids' heads, necessarily since hubby doesn't have time to show all of the science. Once you are at that point, the kids aren't 'learning' astronomy--they are asked to be vessels being filled with someone else's knowledge that they can parrot back. And that is OK in some cases. We should be aware of conclusions even if we are not presented with the actual evidence. We cannot expect children to be experts in every field of study. But if we want experts, than the knowledge that they wish to own, and truly understand with every fiber of their being, should be presented from percepts through abstraction, with each higher-level abstraction firmly tied to the evidence that allows us to know it's true, at least in my opinion. It would be great if every child could be asked 'but how do you know it's true?' and be able to answer it. After doing the work from Real Science for Kids, if you asked the student 'how do you know it's true?' you might get the answer back 'because my teacher tells me', or 'because it's in a book.' Perhaps you will be lucky enough to hear 'because the experiments worked' which is closer to the truth. Given the dismal state of science education today, no wonder so many people believe in absurd ideas with no evidence, 'it's in a book', or 'someone I like told me so', or 'everyone else believes it.'