Science Buddies Blog: January 2010 Archives
Note: This month's "Scientist's Pick" is from Science Buddies' staff scientist, David Whyte. David presented this project to the Science Buddies' team last fall. It's very cool! ~ Science Buddies' Editorial Staff
Project: Smarter Than Your Average Slime: Maze-solving by an Amoeboid Organism
Scientist: David Whyte
Science Buddies' Difficulty Level: 7-9
I was doing some background research on simple organisms that might be used in science projects when I came across an article entitled "Maze-solving by an amoeboid organism." The article contained just what I had been looking for—the basis for a novel project that was both cutting-edge science and also well within the reach of the kitchen scientist.
The basic finding of the research presented in the article was that Physarum, a common inhabitant of wooded areas around the world, can find the shortest path through a maze set up on an agar plate. Physarum, also called slime mold, typically forms a large amoeba-like mass that moves over dead leaves and rotting logs looking for organic matter to consume.
Announcing their findings in the journal Nature, the researchers said they believe the organism changed its shape to maximize its foraging efficiency and therefore its chances of survival. They went on to claim that "This remarkable process of cellular computation implies that cellular materials can show a primitive intelligence."
In the lab, Physarum can be grown in Petri dishes that have a layer of agar on the bottom, so I decided to put Physarum to the test at home.
Conducting the Experiment
To set up the experiment, I placed pieces of slime mold in a 30-square-centimeter (five-square-inch) maze on an agar plate. On that same plate, I strategically placed a food source at two spots in the maze.
The pieces of slime mold coalesced, and the organism condensed its entire body to form a mass that stretched between the two food sources and connected them. In each trial, the slime mold showed its ability to both solve the maze and find the food. Each time, it adopted the shortest possible route, effectively solving the puzzle.
The project idea I created for Science Buddies lets you devise your own maze to see for yourself how the slime mold behaves. You'll have to decide for yourself—is the slime mold "intelligent"? Are there limits to its intelligence?
Other questions you might ask as you work with the Physarum include:
- What environmental cues is it using and how does it process information in ways that allow it to adapt?
- What other tests can be devised to further explore how these remarkable creatures respond to the world as their senses experience it?
For me, any project that involves "cellular computation" and "primitive intelligence" in an amoeboid organism has lots of potential. In this project, what I discovered is that Physarum is a simple organism - one that you can experiment with at home—but it is not really so "simple" after all.
If this project sounds like fun, you might want to explore other Project Ideas in our Zoology section.
While I do cook my pasta the amount of time noted on the box (which may or may not be necessary), I'm one of the laziest sorts of tea drinkers. I drink dozens of cups of tea a day, and each time I follow the same highly unscientific, though orderly, process:
- I grab my cup.
- I grab a tea bag (from the "tea drawer").
- I grab my sweetener (there are science fair project ideas on that, too!).
- I rip open the tea bag and drop it in my cup.
- I rip open my sweetener and dump it in.
- I push the cup under the instant hot water dispenser.
- I fill it up.
- And then I move on with whatever I'm doing.
I don't turn on a timer. I don't look at the time. I don't lift the bag in and out to speed or spread. I don't stir. I don't swirl.
I wait a few minutes before my first sip. But even once I start drinking, I don't take the tea bag out of the cup.
I guess it means that from first sip to last, I'm getting tea of varying strength. Which do I like best? How strong is it really? How much does it change between the strength it is say 2 minutes after the tea bag is submerged in the water and a half hour later when I might drink the last drop?
I don't know. I've never thought of my tea as a budding cup of chemistry, but it is exactly that! There's a chemical extraction going on with each cup I brew. And the resulting infusion varies based on time (and based on other variables like the kind of tea I choose to drink and the temperature of the water used to steep the tea).
A look at the Wikipedia's information on tea suggests that I'm enjoying a less than perfect cup of tea by leaving my tea bag in: "Black teas are usually brewed for about 4 minutes and should not be allowed to steep for less than 30 seconds or more than about five minutes (a process known as brewing or mashing in Britain)."
How much does the tea really change? How many minutes marks the point of no return?
Thanks to a Science Buddies Project Idea geared for budding food scientists and electrical engineers among us, I can find out exactly how the strength of tea progresses over time and how it all boils down to "light" — or how "opaque" the tea is as time passes.
If you want to put your tea (or you mom's tea or your teacher's tea) to the test, you'll find out all the details here:
- How Do You Take Your Tea? Make a Simple Electronic Device to Measure the Strength of Tea (Science Buddies' difficulty: 6-7)
If I knew exactly when I should pull the tea bag out — and what difference it would make — I might change my habits!
If you're wondering about the packet of sweetener, you might also explore this Abbreviated Project idea:
- Sugar vs. Sugar Substitutes: Are They Just as Sweet?* (Science Buddies' difficulty: 2-3)
If you like your science in the kitchen, check out other Project Ideas in the Cooking & Food Science area.
Is pasta on the menu? If you are considering spaghetti and sauce, you may find yourself staring at the pot...waiting for the water to boil. It's best to bring the water to a boil first, right? And it's best to use the amount of water noted on the box, right?
What happens if you cook with less water?
What happens if you put the pasta in with the water at the start?
What happens if you use hot water rather than cold water?
What happens if you use a different kind of pasta?
These are all questions that a seemingly simple dinner of spaghetti can raise.
If you're feeding a crowd, take a look at this science project idea:
- The Pasta Puzzle: How Much Water is Required to Cook Pasta? (Science Buddies' difficulty level: 4)
Not only will this add a scientific boost to your dinner preparations, but you'll have built-in rapidly boiling dinner conversation full of gluten and just a bit al dente.
Twelve Pounds of Pasta?
If you're curious about the outcome of this experiment but can't justify making twelve batches of pasta all at once, set up your lab notebook to record your results and try a different approach over the next few pasta nights in your house.
The project recommends taste-testing to determine if the pasta is al dente. Throwing it against a wall to see if it sticks or not... is a recipe for a mess, not necessarily a formula for perfectly done pasta!
The Golden State Star Party - III
In this final installment in the Golden State Star Party series, I want to discuss the nature of the galaxies that I photographed.
One of the reasons that I like astronomy is that it continually stimulates me to contemplate the vast scale of the objects I observe. M81 is the dominant galaxy in a nearby group of galaxies, about 12 million light years from our own. (A light year is the distance that light travels in one year.) Knowing M81's distance and apparent size in the sky, we can readily calculate that it is about 90,000 light years in diameter.
This has the mind-bending consequence that not only did the photons of light illuminating my camera's image sensor leave M81 over 12 million years ago, but since the photons on the far side of M81 had a greater distance to travel, they had to start about 75,000 years before the photons from the near side. (M81 is tipped from our viewpoint. Otherwise they would have had to start a full 90,000 years earlier.) So, while we think of a picture as representing a moment in time, my picture of M81 is actually smeared out over 75,000 years!
M81 probably contains on the order of 100 billion stars revolving around the center in one of the most beautiful spirals of any galaxy we can see. With my telescope, they all blend together, and even the brightest star is far too small to see. However, a supernova would be visible, and indeed an amateur astronomer discovered one in M81 during 1993. The individual stars surrounding the galaxies in the photo are actually stars in our own galaxy, the Milky Way.
The other galaxy in my photo, M82, was once thought to be an irregular galaxy; however, modern astronomy has confirmed that M82 is also a spiral. Some tens of millions of years ago it had a close encounter with M81, and it was dramatically disrupted. The red at the center is from a giant cloud of dust that is undergoing a massive burst of new star formation.
Other nearby galaxies?
Look at these maps to see the location of other nearby galaxies:
The speed of light is one of the most important constants in physics and astronomy, and it took millennia for mankind to discover a means to measure it. Now you can measure the speed of light in your kitchen using either of these two Science Buddies Project Ideas:
- Using a Laser to Measure the Speed of Light in Jello (Science Buddies' Difficulty Level: 7-8)
- Measuring the Speed of 'Light' with a Microwave Oven (Science Buddies' Difficulty Level: 8)
Ken Hess is the Founder and President of Science Buddies.
In fact, the "Helio Tracker" shown in the Build Your Own Helio Tracker--a Self-powered Mechanical Sunflower that Turns with the Sun abbreviated project idea demonstrates an ingenious and forward-thinking approach to the challenges of going green.
The principles of phototropism tell us that many plants will grow in the direction of their source of sunlight. There are plants, however, like sunflowers, that shift throughout the day in response to the progression of the sun from East to West. These plants are heliotropic. In essence, they "follow" the sun.
Solar panels that can mimic this behavior and reorient themselves throughout the day offer improved efficiency. High-tech solutions exist, but as the science fair project on which this idea is based demonstrates, there is something to learn from a sunflower.
- Build Your Own Helio Tracker--a Self-powered Mechanical Sunflower that Turns with the Sun (Science Buddies' Difficulty Level: 9
For other projects ideas that involve "building" a solution, browse our Mechanical Engineering Interest Area, sponsored by Seagate.
While smaller US earthquakes made recent news, like the 6.5 magnitude shake in Northern California that was felt up into central Oregon, the 7.0 magnitude earthquake that struck near Port-au-Prince, Haiti yesterday, has brought earthquakes into the foreground of national news and media reports - and thus in the awareness of students.
According to reports, the quake in Haiti, an area where earthquakes are not common, was the strongest in 200 years. The world map of earthquakes in the last 7 days on the USGS site shows four earthquakes in the Haiti area, including a 5.3 magnitude shake this morning. While the extent of the damage has not yet been determined, the immediate and visible effects indicate that the quakes were devastating to the small Caribbean country.
The following Science Buddies Project Ideas can help students and classes talk about both the geology of earthquakes as well as civil engineering and the kinds of considerations that go into designing stronger and more earthquake-resistant structures.
Geology of Earthquakes:
- Locating the Epicenter of an Earthquake (Science Buddies' Difficulty Level: 6-8)
- Ring of Fire 2: What Earthquakes Tell us About Plate Tectonics (Science Buddies' Difficulty Level: 5-6)
- How Fast do Seismic Waves Travel? (Science Buddies' Difficulty Level: 5-8)
- Is There a Whole Lot of Shaking Going On? Make Your Own Seismograph and Find Out. (Science Buddies' Difficulty Level: 6-7)
- Building the Tallest Towers (Science Buddies' Difficulty Level: 1)
- Bridges That Can Take a Shake (Science Buddies' Difficulty Level: 2-3)
- Set Your Table for a Sweet and Sticky Shake (Science Buddies' Difficulty Level: 4)
Note: The "Set Your Table for a Sweet and Sticky Shake" project contains a video clip of Courtney Corda, Science Buddies Vice President and "Science Mom" performing the experiment on an episode of "View from the Bay."
Journals and log books are used by researchers and writers in almost every field.
- To make note of "what we do as we do it," we keep a record.
- To ensure we don't forget what happened on this day, we jot down a quick note.
- To remind ourselves later of the affect of this agent on that substance, we document.
A quick look at samples from the over 13,000 pages recorded (often in reverse, mirror-image cursive) by Leonardo Da Vinci shows the range of materials that can appear in a notebook - and the ways in which such notes can later be referenced to track a project or idea. A good journal or lab notebook becomes a historical reference for projects and can help shape future research.
No matter what size project you are working on, you want to make a habit of keeping good records. If treated properly and used diligently, a lab notebook can make a big difference in the process of putting together a final project, a report, or a presentation on results.
When you sit down to write up your project , it will be much easier and less time-consuming if you have thorough and detailed notes of every stage of the process rather than relying on your "memory" of what happened at various points along the way.
Every project differs, so how you approach setting up your book will have a lot to do with your specific project, what kinds of lab-testing you are doing, how many trials you are running, how frequently you measure and collect your data, and even what kinds of background research you are conducting.
There are, however, tried and true practices that can make a difference in how useful your lab notebook is when you get ready to right up your project.
The team of scientists at Science Buddies put together the following set of tips and tricks for using and keeping a lab notebook.
Picking a notebook:
- No sticky notes! A pile of loose paper or sticky notes won't work for a lab notebook. Use a good quality "bound" notebook, so that pages can't be lost, shuffled out of order, or pulled loose.
- Page numbers help. Use a notebook with pre-numbered pages or number the pages yourself. This allows you to easily reference data on other pages via page number.
Tip: Before you start writing in a new lab notebook, go through and number all pages in a consistent location (the top right-hand corner, for example).
Organizing your notebook:
- Claim your book. Put your name, address, phone, email, or other contact information on the first page. It does happen that notebooks and journals get dropped, accidentally left behind, or lost. A lost lab notebook can be frustrating and can really set your project behind. If you've included your contact information, the person who finds your lab notebook can contact you to give it back.
- Organize as you go. Label the second page of your notebook "Table of Contents." As you make entries in your lab notebook, write the page numbers and a description of the experiment or data in the table of contents for easy reference later.
- Neatness counts. All entries should be neat, legible, and complete. Many times you will have to refer back to data that you recorded a while ago. You do not want to be confused by what you wrote because you were in a hurry and made a sloppy entry.
- Keep it in order. Be sure and date each entry you make in your notebook. The entries should be sequential, but dating entries is standard practice.
- Beware the smear! Use a smudge-proof pen when making entries. If you make a mistake in your notebook, simply cross it out and initial below the crossed out section.
When and what to write in your notebook:
- It all counts! Your lab notebook is like a science diary. Write down all of your hypotheses, questions to look up later, and background research. As you are working, write down all your experimental observations or thoughts, no matter how small or insignificant they may seem to you at the time. The little detail you don't record might be exactly what you need to know later -- or what will help you answer a teacher or science fair judge's question!
- Who said that? Write down the names, phone numbers, or email addresses of people you have contacted for your experiment.
- Never leave home without it. Always have your notebook with you when doing your experiments.
- Start fresh. Open your notebook to a blank page before you start experimenting during each new lab session. You do not want to start an experiment and then have to stop because you have nowhere to record data.
- A picture can be worth a 1000 words. Draw pictures of your experimental set-up, experimental results, and so on in your notebook. You can also take photographs and paste them in your notebook.
- Include the extras. You can add printouts and other documentation. Just remember to tape or glue in the material in the proper chronological location. Tip: Add notes describing the attached data so it is clear later "why" you've included the material.
- Don't wait. Record data right away in your lab notebook. Don't rely on your memory because you can forget what happened when you performed the experiment.
- Only in the notebook! Don't be tempted to record data anywhere else but in your lab notebook. Scraps of paper can be lost along with important data.
- Be thorough. Include enough information about what you are doing so that you, or someone else, could reproduce your procedure.
- Add it up. Whether you are figuring out how much of a reagent to add or analyzing your data, make sure to do all your math calculations in your lab notebook. This way if something goes wrong later, you can go back and double check to see if you made a simple arithmetic error.
- Don't jump around. If you need to skip pages between entries for a project, add notes saying where the next entry can be found and where the previous entry occurs.
- Track edits. If you need to go back to a page to change or correct something, use a different colored ink and initial and date the changes.
Special thanks to Sandra, Michelle, Kristin, and Dave for helping pull together their best tips and tricks for using a lab notebook!
Want one more tip that professional researchers and scientists use? Do not leave large parts of pages blank. If part of a page is blank, you might be tempted to scrawl an unrelated note in the blank space later (or someone else might pick up your notebook and make a note in a blank space). When you finish taking notes during a lab session or after recording data on a given day, draw a diagonal line through the unused portion of the page. This clearly marks any "unused" sections. You'll know later that no data or notes should appear in those spaces as you review your work.
Share Your Tips!
Do you have favorite tricks of your own? Leave a comment to share your favorite lab notebook practices so that others can take advantage of what you're doing right!