Not your usual experiment, this is a book: “The League of Scientists” is a young adult fiction book by Andy Kaiser (the creator of Digital Bits Science Lab).

Equipment needed:

The League of Scientists is available here: http://www.LeagueOfScientists.com

The Digital Bits Science Lab Experiment:

The League of Scientists is a group of smart kids who love science. They use their knowledge and critical thinking skills to solve seemingly-supernatural mysteries.

One of the components of the book is the mystery aspect, and not just the “main” mystery. In most chapters, there is a puzzle. The solution to the puzzle involves the application of science or critical thinking. The book is intended to give science education (and scientific applications – something you don’t always get from such fiction) while still giving kids a good story and characters.

One of the classic fun things to do with a balloon is to “squeak” it. This easy game is the result of some interesting science – air pressure and sound at the molecular level. This is also very similar to the way we use our vocal cords to speak.

Equipment needed:

Balloons

The Digital Bits Science Lab Experiment:

Blow up a balloon. Hold the mouth of the balloon in both hands. Stretch the mouth, pinching your fingers on the balloon while pulling them apart, as in the picture below.

As the air flows out of the balloon, you’ll hear a high-pitched, loud squeaking noise. You can adjust the tension on the balloon mouth, and the pitch and volume of the squeaking will change.

What’s happening here? Why does a balloon squeak when you stretch the mouth?

Stretching the mouth of the balloon makes a very tiny space for the air to flow out of the balloon. The air pressure of the balloon itself forces the air out the mouth, but because of the stretching, that space is limited. The airflow causes the balloon mouth (the stretched part) to vibrate. The vibration makes the noise.

Put your hand on your upper neck – right under your jaw – and hum. You’ll be able to feel a vibration, similar to the vibration at the mouth of the balloon. This is air being forced over your tightly-stretched vocal cords. Remember how tightening or loosening the balloon mouth changed the sound of the squeaking? Hum in a high pitch and feel your neck. Hum in a low pitch, and the vibration will change.

You talk using a similar method to the way the balloon squeaks. But the balloon experiment is a simple demonstration, capable of just a few annoying noises. Your body is a highly-developed machine. You can make noises a lot more impressive than any balloon.

This is a fun experiment showing an interesting limitation of the human body: follow the instructions below, and try to open your fingers to simply drop an object. You won’t be able to do it!

Equipment needed:

A pair of hands (yours will work fine)

A friend

A small, flat object (a coin or bottlecap will work fine)

The Digital Bits Science Lab Experiment:

Clasp your hands together, folding all fingers down. Then fold up your ring fingers. Have your friend put the small, flat object between your two ring fingers, like so:

Now, try to separate your ring fingers and drop the object you’re holding.

You can’t.

You may notice you can slide your ring fingers from against each other, but you can’t actually move them apart.

What’s happening here? This is an easy demonstration of some of the limitations of the human body. When your hands are clasped together in that particular way, your tendons are pulled so that your fingers can’t move outward.

Your body is a well-functioning, intricate mechanical device. When you look at a human body, don’t think of it as a single unit. Realize that inside, there are many pieces and parts that work together. And in this experiment, you can put the body in such a position so that some of those parts don’t work!

Equipment needed:

Plastic drinking straws

Scissors

The Digital Bits Science Lab Experiment:

What we’re trying to do is to create a simple musical instrument out of a plastic straw. It’s pretty easy. First, cut the top of a straw into what looks like a triangle. (It may help if you squish the straw end first before cutting it – this ensures the cut is the same for the top and bottom of the straw.) When you’re done, one end of your straw should look like this:

Next, blow into the straw. You’ll need to blow pretty hard, and your lips will seal firmly around the straw right at the point where you first made the cut. You may have to move the straw back and forth a bit until you find the right place. The parts of the straw should be flat, and parallel with your tongue – don’t rotate the straw, or the noisemaking will get very difficult or impossible. When you’ve got the right technique, you’ll be rewarded with a buzzing noise coming from the end of the straw.

This is it – we’re making sound! This is the same noise-making concept as reeded musical instruments, like the clarinet and oboe: blowing air over a reed (in this case, our cut straw end) makes that reed vibrate. When it vibrates at the right speed, it makes a noise. A similar technique also allows you to talk. Your vocal cords are just like this straw: you blow air over your vocal cords, and your vocal cords vibrate, and this makes noise come out of your mouth. The difference is that in speaking, your mouth, tongue and many other factors work together. They change various parts of how the air flows and how fast your vocal cords vibrate. This control allows us to form words, sing, and make many other interesting noises.

You can use this concept with our “straw clarinet”, too: cut the straw at the other end (the end you don’t blow into). Shorten it. Make more “straw clarinets”, and cut them to several different lengths. When you blow into these, you’ll find the noise is different from each one. Finally, if you’re really talented, try blowing while changing the tightness of your lips, or varying the amount of air you’re blowing – you’ll find that the noise will change as well.

Equipment needed:

A shoebox

Black duct tape or black paint

A tape measure

Wax paper

Scissors

A heavy blanket

Rubber bands (optional)

The Digital Bits Science Lab Experiment:

To begin with a picture, here’s the finished pinhole camera:

Granted, this isn’t a true pinhole camera. It’s more of a pinhole viewer, or a pinhole camera without any film. With a small modification, you could convert this viewer into a film-based pinhole camera. But for the purposes of this science lab, this pinhole viewer is more fun to use for smaller children, and effectively demonstrates how the eye works, without bringing in the complexity of film and development.

Take your shoebox and make the inside of the lid and box black. Paint it, or use a wide, black tape. You’ll see that due to running out of tape halfway through, I used both techniques in my shoebox. The black color prevents light from bouncing around inside the box, which would interfere with our pictures.

Put the lid on the box. Tape the top on, or put a rubber band around it – we want it in place for the rest of the setup and usage.

Use the scissors to twist out a small hole in the center of one end. See the photo above for detail – this is a small half-inch hole. Don’t make it any bigger.

Now to the other end of the shoebox: we need to make a viewfinder. It’s just a piece of wax paper taped in place over a two-inch by two-and-a-half-inch-wide square. Cut out the square, then tape the wax paper over it. Try to get the wax paper to be as smooth as possible. Wrinkles or ripples aren’t a big problem, but the more you have the more they’ll interfere with your images.

And that’s it – we’re finished, and our pinhole camera is ready. As you use the camera with the directions below, keep two things in mind:

1) The camera works best when you aim at a brightly-lit object. For example, things under full sunlight, or other things illuminated by a bright light bulb.

2) In order to be able to see the image displayed on the wax paper, you need to block out any ambient light: drape an opaque blanket over your head and the camera. That should keep things dark enough to see the light projected on the viewfinder. The majority of light hitting your eyeballs should be what’s coming out of the pinhole camera.

To use the pinhole camera, you need to point the small hole at one end at whatever you want to view. Hold the camera so it’s about a foot away from your face – you may have to move the camera towards and away from your face until you see an image appear on the wax paper. 

As you see the images in the pinhole camera, you’ll see something interesting: the images appear upside down and backward!

Here’s a photo of what I saw during my test:

It’s a little small, as it should be – this was my attempt at taking a picture of the wax paper with a digital camera held at viewing distance.

However, see what happens when we zoom in the picture and flip it upside down:

Still doesn’t make much sense? Perhaps not, but here’s a photo of the actual scene the pinhole camera was looking at:

Seeing the original scene, the pinhole camera version should now make sense. It’s blurred from a combination of the camera having no focus, and the wax paper itself messing with the image quality, but it’s still a snowman standing next to a swingset.

What’s happening here?

Light enters the small hole in our pinhole camera. The small hole only allows a little bit of light to enter, and the light that does enter is projected on the wax paper upside down.

A pinhole camera is a great example of how our eye works: the “small hole” in our eye is the iris. Light enters the iris and is projected on to the back of the eye, the retina. The retina is just like the wax paper. Everything you see, including the words you’re reading right now, is projected upside-down on the back of your eye! The brain takes this signal from the retina and flips it “right side up”.

The eye itself is a pretty remarkable organ, but the basics of photography and sight are pretty simple.

How does a color TV show colors? How does a computer monitor show colors? Use a hand magnifier to see how a computer or color TV displays such a wide range of colors.

Equipment needed:

A good hand magnifier. A standard low-power magnifying glass will work, although, like other optics, you get what you pay for. A nice Hastings Triplet Magnifier will cost more, but between the 10X magnification and the clear, distortion-free image I think it’s worth it if you plan to use it much.

A color display. Like the one you are probably using right now to read this. Although, if you only have a low-power magnifier, it will be easier to see how it works if you use a color television instead of a computer display.

The Digital Bits Science Lab Experiment:

Look at the test pattern picture below with your magnifier. (Click on the photo to view the full-size version.)

You can also turn on your TV to something that shows different colors and look at that.

What you will see is that, close up, the screen really only shows three colors: tiny rectangles of red, green, and blue. The rectangles are so small that, from a distance, they all blur together and your eye mixes the colors.

To make different colors, the display makes the rectangles brighter and dimmer. If you look at the test pattern picture, you can see that each color is different brightnesses of the colored rectangles.

Your veins and arteries carry blood and nutrients around your body. Demonstrate “you are what you eat” with a little help from celery.

Equipment Needed:

Glasses

Celery

Water

Liquid food coloring

The Digital Bits Science Lab Experiment:

Pick a couple of colors of food coloring (hint: green may not work as well, as it’s too close to the color of the celery). Put three drops of the food coloring into your glasses, and fill the glasses halfway with water.

Cut your celery so that, when placed in the glass, you have half of the celery in water, and the other half out of water:

Let the celery sit in the glasses overnight.

The next day, look at your celery. In the picture below, you’ll see two celery sticks cut in half. One stick was soaking in blue water, the other in red. The parts labeled “bottom” were the parts submerged in water overnight. The parts labeled “top” were sticking out above the water overnight.

Notice the food coloring leaking out of the “top” pieces.

What’s happening here? When placed in the water, the celery uses it like it always does – it draws the water up into its “vascular bundle“, the thin lines that are the transport system of a celery stalk. Similar to the way blood flows in our own veins and arteries (as pumped around by our heart), the celery’s vascular bundle uses a process called “transpiration” to move its liquid nutrients.

Our bodies need nutrients and liquids to live, just like a stick of celery. Now, we don’t just sit down in a glass of water; we drink it! But the concept is similar – what we take into our bodies spreads to most every other part of our body. We are what we eat (and drink).

A simple demonstation of “muscle memory” and the subconscious actions of our body.

Equipment Needed:

You

A doorframe or wall

The Digital Bits Science Lab Experiment:

This experiment will assume you’re standing in a doorframe, but really the experiment will work fine with any heavy, large object.

Stand inside the doorframe. Stand normally, but stand so that one arm is directly against the wall. Push outward – away from your body – with your wall-touching arm, as if you wanted to flap your arm. It will be stopped by the doorframe, as in the picture below:

Now, keep pushing! And push some more! Count slowly to thirty, pushing your arm out against the wall the entire time.

Then, step away from the wall. Relax both your arms, and let them hang limp at your side.

But watch what happens: the arm you were pressing against the wall will start to rise!

What’s happening here? Your muscles have memory: when you press your arm against the wall for so long, your arm muscles get so used to pushing against the wall, they continue to push even after you’ve stepped away. And since your arm muscles are still pushing, your arm raises up into the air. Evenutally, your arm muscles will realize you are no longer pushing, and your arm will lower back down.

“Your Multimeter and You”: use a multimeter to measure electrical resistance of things, including yourself.

What is a multimeter? Multimeters are instruments to measure several different things, including electrical conductivity, electrical current, and electrical voltage. You can get very cheap ones (see the photo below). You’ll find them at hardware stores for approximately $10 – $20, or you can spend tens, hundreds, or even thousands of dollars for really high-end professional models.  I recommend one of the cheap ones. These can either have a needle and dial reading like the one shown here (analog multimeters) or a numerical display (digital multimeters).

Equipment Needed:

A multimeter, either a digital multimeter or an analog multimeter.

You

A metal object, like a coin

A piece of plastic, wood, or glass

A pencil with the eraser pulled off of one end so that you can see the pencil lead

The Digital Bits Science Lab Experiment:

A multimeter has many different settings, the one we are going to use is one of the ones marked “R” (for resistance) or “Ohms”:

This setting is used to measure how easily electricity flows through an object. What the multimeter does is this: it has a battery inside that is connected to the probes.  When you touch the probes to an object, electricity flows from the battery through the object.  If a lot of electricity flows, that means the object has very little electrical resistance, while if hardly any electricity flows, that means the object has very high electrical resistance. The multimeter measures the electrical current flow, and uses this to calculate the resistance of the object in units called “Ohms”.

So, turn the settings selector on your multimeter to measure resistance. First, check the calibration of your multimeter.  With the probes not touching each other, the reading should be “infinite resistance”, meaning no electricity is flowing. When you touch the probes together, the multimeter should read zero resistance, meaning that the current is flowing through the probes as quickly and easily as possible.

Now, we are ready to make some measurements. 

First, check a metal object: the resistance should be very close to zero ohms because metals are very good conductors of electricity.

Next, plastic or wood: the resistance should be extremely high, because these are all very bad conductors of electricity (insulators).

Now try the pencil: touch the multimeter probes to the lead on each end of the pencil.  You should get a reading of somewhere around 10 to 100 ohms. This means that the pencil lead (graphite) will conduct electricity, but that it is not as good of a conductor as most metals.

Finally, try yourself: grab hold of one probe in each hand, and see what your resistance is (don’t worry, the battery in the multimeter is not strong enough to give you a shock).  If your hands are dry, you will probably have nearly infinite resistance.  If your hands are sweaty, or if you lick your fingertips before taking hold of the probe, you should have
a resistance somewhere around 50,000 ohms.  If you touch the probes to your tongue, the resistance should be much lower.

So, this means that while your body has a lot of resistance, it has less resistance than an insulator like a piece of wood.  This is why you can get electrically shocked (because electricity can flow through your body), and why electrical appliances near water are a bad thing (because if you are wet, you have a lot less electrical resistance than if you are
dry).

Ants. They’re not just for driveways anymore.

Equipment needed:

An ant farm. While there are the traditional sand-filled ant farms, my latest favorite has been the Fascinations Antworks ant farm. The tunnel and farm medium, instead of sand, is a cool-looking gel. It’s cleaner. The tunnels are more stable, and are less likely to collapse from vibration or movement of the ant farm. The gel also provides food for the ants, so you don’t have to feed them. And the gel is transparent, so you can easily see the ants and their tunnels in three-dimensional glory.

Ants. You can get 25 Western Harvester ants for about $5. If you don’t want to mail order them, you can always dig some up in the back yard. Note that Western Harvester ants are medium-sized with larger mandibles. They’re great for ant farms – very visible and active – but they’re not for cuddling: They can and will bite (or pinch), so keep them in the ant farm.

The Digital Bits Science Lab Experiment:

An ant farm is a great intro into several biological and behavioral concepts:

There is, of course, the study of insects and ant biology. Watching them dig tunnels is fascinating. And not in a lava-lamp kind of way, but in a logical, workhorse way: Ants are directed by very simple rules, but those simple rules can produce complex results, like the complexity of the ant community and the tunnel systems.

Also make notice of the group effort: Like Egyptian slaves laboring to build the Pyramids, or herds of animals fighting off predators, an ant farm is a great way to show how group effort and cooperation can accomplish more than a single individual ever could.

And, perhaps the most important thing a child will enjoy about an ant farm: Bugs! What young child doesn’t like creepy crawly bugs? The ant farm lets them get as close as they want, without worrying the parents.

For more insectile fun, check out The Backyard Arthropod Project. The author’s project is to catalog as many arthropods (mostly insects and arachnids) as possible inside and around his house. Great for close-up pictures of arthropods, as well as interesting stories and information about each one.