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.

Experiment with electricity using a multimeter and a battery.

Equipment Needed:

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

A battery. A standard AA, C, or D battery will do nicely.

A piece of wire. A straightened paperclip is fine, although any wire long enough to go from one end of the battery to the other will be good.

The Digital Bits Science Lab Experiment:

There are two characteristics of electricity that get measured regularly: the “voltage“, and the “amperage“, or current.

In some ways, electricity is kind of like pumping water. The “voltage” corresponds to how much “pressure” there is forcing the electricity through things, while the “amperage” corresponds to the actual “quantity” of electricity. So, if water were electricity, a big slow-flowing river would have a very low voltage but a very high amperage, while a stream of water jetting out of a power washer would have a very high voltage but a very low amperage. A battery is kind of like a pump for electricity.

So, we will use your multimeter to measure both voltage and amperage of the electricity from a battery, and see how it changes when we “short the battery out”.

First, turn your multimeter selector dial to “DC Volts“, at the lowest range. Touch one probe to each end of the battery. If it is an unused AA, C, or D battery, it should read 1.5 volts. (If you are using an analog multimeter, and the needle tries to turn the wrong direction, just swap the ends of the battery that the probes are touching).

Leaving the probes on the ends of the battery, short it out: take your bit of wire and bend it so the wire touches both ends of the battery. The voltage that you read should drop quite a lot, maybe to almost zero. This is as if we had a power washer, and punched a hole in the hose so that the water could get out more easily, making the pressure drop. If you leave the wire touching both ends of the battery for more than a few seconds, it will start to get hot, so don’t leave it on too long.

Now, turn your multimeter selector knob to “DC mA“. That stands for Direct Current milli-Amperes. Most multimeters only measure up to 250 mA, and when you touch the probes to the battery ends, it will go off the scale (for an analog multimeter), or display some message about being “out of range” (for a digital multimeter). This means that the battery is able to supply a lot more electrical current than your multimeter can measure.

Still leaving the probes on the battery, short it out again with your piece of wire. Now, instead of being out-of-range, the current will drop to something you can read on your scale. Basically, most of the electricity is flowing through the wire, and your multimeter is measuring the current that is “left over”.

See how the electrical conductivity of water changes depending on what is dissolved in it.

Equipment Needed:

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

Two or three identical containers for water, like drinking glasses or transparent jars

Distilled water. Grocery stores sell bottled distilled water, usually near their bottled drinking water. “Distilled” means it is high-purity water with nothing dissolved in it

Tap water

Baking soda

Sugar

Table salt

A measuring spoon

The Digital Bits Science Lab Experiment:

First, fill one container with distilled water, and set your multimeter to the “ohms” setting for measuring electrical resistance. Touch the multimeter probes together to check that the zero setting is correct. Then, stick the tips of your probes into the water so that the metal part is completely underwater, holding them an inch or so apart. The electrical resistance should be very high.

Next, put some baking soda in the water – about a teaspoon in an 8-ounce glass. Stir it up until the baking soda dissolves, and measure the electrical resistance again. The resistance should be much lower.

Now, fill a series of glasses, with the following

Tap water
Distilled water + 1 teaspoon sugar
Distilled water + 1 teaspoon salt

…and measure the electrical resistance of each. How are they different?

What is going on here?

You should notice that water by itself is not very conductive; that some things (baking soda and salt) make the solution a lot more conductive; while other things (like sugar) do not. What is happening is this: Really pure water is actually an insulator, and does not conduct electricity very well, so it has a high resistance. But, a lot of things that dissolve in water “dissociate”, that is, they break up into electrically charged parts (ions) that can move around. When the ions move, they conduct electricity. Substances that dissolve in water and form ions like this are referred to as “electrolytes”, because they make it possible for water to conduct electricity.

Not all things that dissolve in water are electrolytes, though – the sugar will not make the water very conductive, because sugar dissolves without breaking up into ions. If your sugar did increase the conductivity a bit, it was probably because it had small amounts of some impurities that were electrolytes.

The tap water should have been more conductive than the distilled water, but not as conductive as the water with salt or baking soda dissolved in it. This is because the water out of your tap is not pure, it has minerals like calcium carbonate dissolved in it. Depending on where you live, you could have “hard” water (which has a lot of dissolved minerals in it and is quite conductive), or “soft” water (which has very little dissolved minerals, and can be almost as non-conductive as distilled water).

You can check the conductivities of other liquids, too, like cooking oil, vinegar, or soda pop. Also, see how adding just a little bit of baking soda or salt to water changes the conductivity, compared to adding a large amount.

Description:

A simple demonstration of electrolysis – electrocuting water to convert it into hydrogen.

Equipment Needed:

A 9-volt battery

Wire (something low-gauge and flexible is preferred, like copper wire)

Scissors

Wire stripper (optional, if you’re handy with scissors)

Tape (durable tape is required, like duct tape or electrical tape)

A glass of water

Salt

The Digital Bits Science Lab Experiment:

This experiment is a simple demonstration of electrolysis. Electrolysis is the method of breaking apart compounds into their original elements by passing an electric current through them.

Put simply, this experiment shows that if you electrocute water, you’ll get hydrogen.

First, we need to make the electric device that will make the electrolysis happen: get the 9-volt battery, your wire, the scissors and tape. Start stripping the ends of the wire. You will need two strands of wire at least six inches in length. Use the wire stripper or the scissors to strip the rubber sheath from both ends of each wire with the scissors. This will expose the wire itself:

After you’ve stripped both ends from both wires, take one wire and securely tape one stripped metal end to one terminal of the 9-volt battery. Next, do the same with the second wire – tape it to the remaining battery terminal. The result will be our electrolysis device, all ready to go:

The rest is easy:

Get your glass of water. Put a tablespoon or two of salt into it. Stir the salt to dissolve it. The water will become a little cloudy.

Get the electrolysis device. Dip both ends of the wire into the salt water.

You will immediately see bubbles start to fizzle off of one wire. (If you don’t see bubbles, then check to make sure that your wires have a good connection to the battery, and that the battery still holds a charge.)

What’s happening here? These instructions are simple do-it-yourself electrolysis: when you electrocute water (which is made of hydrogen and oxygen), the electricity breaks apart water molecules. The bubbles you see are the hydrogen from the water being released. Salt water improves the electrolysis reaction - fresh water (like in the picture above, since cloudy salt water was difficult to photograph) will still give you bubbles of hydrogen, but it won’t be as impressive as with salt water.
 

“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).