Kid-Friendly Science Experiments for Winter Break
For Argonne National Laboratory employees and friends, winter break doesn’t have to be a break from science. Here, we’ve curated a few, simple science experiments you and the young scientists in your household can try over the holidays.
(Adults, please remember to supervise children to make sure they safely complete each experiment.)
The experiments are featured below in PDF format and can be downloaded as well as in text format.
How Do You Split Water to Get Hydrogen?
Molecules of hydrogen and oxygen make strong bonds to form water, H2O. When an electrical current is sent through water, these bonds can be broken. The process of splitting water molecules with an electrical current is called electrolysis. Electrolysis involves the movement of electrons, charged particles in atoms. Electrons tend to flow in certain directions, but we can force them to change direction with a battery. The battery acts as an “electron pump.” During electrolysis, electrons are pumped into the water molecule, causing the bonds to break. This flow of electrons can be thought of as an electrical circuit.
Scientists are studying the best ways to use electrolysis to power cars and batteries. In this electrolysis experiment, you will split water to form chlorine gas. Using graphite pencils, electrical wire and a battery, you will send an electrical current through a mixture of water and salt to split the water molecules. You’re adding salt to the water because pure water is not a good conductor of electricity. Salt is an electrolyte that helps the electrons flow even though water is a poor conductor. The pencil tips are completing our electrical circuit, just like the positive and negative ends (called cathodes and anodes) of a battery complete a circuit. To keep the chemical reaction going, some water molecules need to lose electrons and some need to gain electrons. One of the pencil tips in the water is the cathode where water molecules are gaining electrons, and the other pencil tip in the water is the anode where water molecules are losing electrons.
What you need:
- Glass of water
- Two No. 2 pencils
- Pencil sharpener
- 9-volt battery
- Electrical wire (about 12 inches)
- Table salt
- Thin cardboard
- Remove the eraser and metal band on each pencil.
- Sharpen both ends of both pencils so that you have four pencil tips.
- Cut the cardboard to fit over the glass with a little room to spare. Wait to place the cardboard on top of the glass.
- Space the two pencils about an inch apart then push them through the cardboard cover. Set the pencils and cardboard aside.
- Pour warm water into the glass.
- Dissolve about one teaspoon of salt into the warm water and let it sit for a few minutes.
- Cut the electrical wire into two pieces. Using the first piece of wire, connect one end to the positive side of the 9-volt battery and tie the other end to one of the black graphite pencil tips to connect it. Repeat this step for the second piece of electrical wire, connecting it to the negative side of the 9-volt battery and the other pencil tip.
- Now, place the remaining two pencil ends into the water and salt mixture and rest the cardboard cover on the glass.
- Look for the bubbles near the pencil tips in the water.
Source: Energy Quest
Which Kind of Light Bulb Produces More Waste Heat?
The incandescent light bulb has been around for more than 100 years. In that time, engineers have also invented fluorescent and light-emitting diode (or LED) bulbs. Fluorescent and LED bulbs use less energy to give off the same amount of light as incandescent bulbs, and they last longer. By replacing the incandescent bulbs in your home with energy-saving fluorescent or LED bulbs, you are helping save electricity.
When a light bulb wastes energy, it turns some of that energy into heat instead of light. This heat does not serve a purpose so it is called “waste heat.” In this experiment, you will measure the amount of waste heat given off by an incandescent bulb then compare it to the amount of waste heat given off by an energy-saving fluorescent bulb. The hotter the bulb, the more waste heat it is emitting.
What you need:
- Alcohol or digital Thermometer
- Make sure the thermometer records a wide temperature range, such as an indoor/outdoor thermometer. Some digital thermometers designed to check for fever may not show low temperatures.
- 25-watt incandescent bulb (or another low-watt bulb like a 40-watt bulb)
- Many incandescent bulbs now use halogen gas to make them more energy-efficient and may be labeled halogen bulbs. They will work for this experiment.
- 100-watt incandescent bulb
- Watch or timer
- Two fluorescent bulbs (usually labeled CFLs for compact fluorescent bulbs) that produce lumens comparable to the incandescent bulbs.
- You can check the lumens (meaning the brightness of the light emitted by the bulb) on the box just like you would check for watts. For example, a 100-watt incandescent bulb may have the same lumens as a 23-watt CFL.
- Put a 25-watt incandescent bulb in the lamp and turn it on. Wait five minutes.
- Hold the thermometer six inches above the bulb for one minute and record the temperature. Turn off the lamp.
- Let the bulb cool, remove it, put in the 100-watt light bulb, and turn the lamp back on. Wait five minutes.
- Again, hold the thermometer six inches above the bulb for one minute and record the temperature. Turn off the lamp.
- Repeat the procedure with the fluorescent bulbs.
- Bonus: You can also try this with LED bulbs.
How Do You Make a Borax Snowflake?
A solution is two or more substances (solute and solvent) that are mixed. The solute is a substance that is added to the solvent, like adding Kool-aid powder (the solute) to water (the solvent) to make a flavored drink.
How much solute you can dissolve in the solvent depends on the pressure, temperature and the characteristics of the substances. Every solvent has a saturation point at which no more solute can be dissolved in that solvent. When a solvent is at a high temperature, you can dissolve more solute than you can when the solvent is at room temperature. Then, when this solution is cooled to room temperature, the extra solute that was able to dissolve at a high temperature falls out of the solution and crystalizes. This is why you sometimes see sugar crystals at the bottom of a cup of tea or hot chocolate that has gotten cold.
Crystals, like sugar, are solid materials that are organized into a pattern, so that when you look at them closely, they are shaped like squares, octagons or other geometric shapes. Scientists grow crystals from all different kinds of substances to study their strength, flexibility and other properties. In this experiment, you will make Borax crystals by dissolving Borax powder in boiling water. The high temperature of the water allows more Borax to dissolve than would at room temperature. But once your Borax solution starts to cool, the extra Borax will begin to crystallize, creating something pretty neat.
What you need:
- Pipe cleaner (at least three pieces)
- Borax powder – not Borax powder mixed with detergent
- Wide-mouth pint jar
- Food coloring (optional)
- Connect the three pieces of pipe cleaner at their centers to form a six-pointed, snowflake shape. If the snowflake is too wide to fit into the pint jar, cut the six ends of the snowflake so that it will fit.
- Tie a string to one of the six ends of the snowflake. Set the snowflake and string aside.
- Boil water and pour the hot water into the pint jar. The jar should be almost full, but leave enough room so that water won’t spill over when you submerge the snowflake in the jar.
- Mix the Borax powder into the hot water until it dissolves. You should use about three teaspoons of Borax per cup of water (or five to six teaspoons if your pint jar is nearly full).
- If you want to dye your snowflake, add food coloring to the water and Borax solution.
- Dip the snowflake into the pint jar so that it is completely submerged in the solution. Tie the loose end of the string to a pencil or utensil and balance it on top of the jar so the snowflake stays in place.
- Leave the snowflake in the jar overnight. Borax crystals should form on the pipe cleaner, creating your Borax snowflake.
What Happens to a Balloon at Cold Temperatures?
When a balloon is filled with helium, the helium expands the balloon by increasing the pressure inside. That’s why when you pop a balloon, it shrinks and blows out a lot of air—it’s depressurizing. But there’s another way to depressurize a helium balloon that is less destructive.
Pressure and temperature are directly related. Pressure is caused by the helium gas atoms colliding with the walls of the balloon. Each collision is a tiny push, but when you multiply that by the billions and billions of atoms inside the balloon, it adds up to a lot of force. Temperature is a measure of the speed of the atoms. If you move a helium balloon from warm to cold air, the cold temperature causes the helium atoms inside the balloon to move slower. Since the atoms are moving slower, they are colliding with the balloon less frequently and with less force, so they are decreasing the pressure on the balloon and shrinking its size.
In this experiment, you will shrink a helium balloon by moving it from the warm indoors to the chilly air outside. (This experiment works best on a particularly cold day.)
What you need:
- A helium balloon
- Fill a balloon with helium, or buy a helium balloon at the store.
- Keep the balloon indoors for a few minutes.
- Take the balloon outside into cold temperatures and watch it slowly deflate.
- After a few minutes outside, take the balloon back inside and watch it re-inflate.
How Does a Computer Find Mistakes?
Computers send and receive a lot of information. They help us deliver messages, transfer money, buy products online, and store and share books, music and pictures. It’s important that the information that is sent between computers, called data, does not contain mistakes or errors.
Data is often transmitted as sequences of ones and zeros called bits. One way to detect errors in data is by searching for parity, an odd- or even-numbered sequence of bits. If a sequence should have odd parity but, instead, has even parity, some piece of information is missing or changed.
Scientists use computers for all kinds of research and experiments. Making sure that data is error-free is important to finding the right answers to a scientific problem quickly and conducting an experiment correctly. In this experiment, you will help detect an error in a sequence of cards (the bits) using odd and even parity.
Note: In this experiment, someone serves as the instructor in order to teach the concept to the participant.
What you need:
- A deck of playing cards
- In the following step, the cards can be placed either with the face up or the back up. The face and back correspond to binary numbers (ones and zeroes) used to encode information in computing.
- The participant should lay out cards in a rectangular shape of five rows and columns (25 cards total). This can be done in any combination of ones and zeroes (faces and backs).
- The instructor then lays down an extra row and column. These new cards should be placed so that there is an even number of face cards in each row and column.
- The instructor asks the participant to turn over just one card—any card—while the instructor is not looking. When the instructor looks back, they should be able to see which card was changed because it will introduce an odd number of face cards in that row and column.
- Ask the participant how they think the trick is done. Explain how the error was detected.
Source: Computer Science Unplugged
What Does Salt Do to Ice?
You have probably been warned that when it is really cold outside the streets and sidewalks can be slippery with ice. Also, you may have noticed that during the winter, streets and sidewalks are covered with salt before and after it snows to help “melt” the ice. Ice doesn’t have special salt-melting powers, but as you will see in this experiment, a mixture of salt and water freezes at lower temperatures than water alone, which is why salt appears to melt ice and snow. Pure water always freezes at the same temperature: 32°F or 0°C. Above 32°F, the water molecules are free to move around. When water freezes, the molecules slow down and start forming strong connections between each other. Eventually, they stop moving around. The result is ice.
However, if there is something else in the water, such as salt, it is more difficult for the water molecules to connect to each other and form a solid because the salt atoms get in the way. To freeze a mixture of salt and water, the water must be cooled even lower than its normal freezing temperature to turn into a solid.
What you need:
- Four plastic cups
- Measuring cup
- Table salt
- Alcohol or digital Thermometer
- Make sure the thermometer records a wide temperature range, such as an indoor/outdoor thermometer. Some digital thermometers for checking for fever may not record low temperatures.
- Fill four cups with six ounces of tap water (three-fourths a cup).
- Add a teaspoon of salt to the first cup, two teaspoons to the second, three teaspoons to the third and none to the fourth.
- Place the cups in the freezer. Check on them periodically until a thin layer of ice forms on the top of the water.
- Use the thermometer to record the temperature of each cup.
- Compare the temperatures of the cups to the amount of salt in each cup.