3 Fun Countertop Ice Maker Experiments for Kids
During the winter sometimes kids have to play indoors because of inclement weather. Here are 3 fun experiments to do with ice be it from the outside or something like a countertop ice maker.
Vortex and Ice Cubes
A simple and straightforward experiment that uses common household items to create a vortex. Vorticies in water like a whirlpool occur when a column of water rotates in a circular fashion. Water on the outside of the column has to move faster than the water inside creating a strong current.
- A large container like a pot
- Something with which to stir
- Ice, preferably cubed.
- Food coloring if you choose
- Heat some water. It doesn't have to be boiling but it should be much hotter than room temperature.
- Pour the water into your container so that the water level is at least 3 inches.
- Stir the water slowly in a single direction. Add a little food coloring if you have difficulty seeing the water rotating.
- Place a cube of ice in the center of the container and watch it spin faster than the surrounding water. You may have to test different locations and speeds to get this to work properly.
The melting ice turns into water that sinks away from the bottom of the cube. Warm water is drawn upwards towards the edges of the vortex. A vortex doesn't have to be very strong or fast to be called a vortex. When the cold water exchanges for the warm water it rushes inward causing the cube to spin faster.
Colorfully Melting Ice with Salt
Warning, this can be messy! Use non staining coloring or perform this experiment in an area where clean-up will be easy.
- Various sized containers that are freezer safe to make ice
- Salt (table salt is fine)
- A tray with a big lip, like a baking tray, to hold melting ice
- Towels for any leaks
- Food coloring or liquid watercolor paints
- A spoon, turkey baster or droppers
- Cups to mix the coloring
- Fill containers with water and let them freeze overnight.
- The next day, mix colors in cups.
- Place towels on whatever surface you will be using for the experiment.
- Place tray on top of towels.
- Remove ice from the containers and place on the tray.
- Sprinkle small amounts of salt on top of the ice shapes.
- Be careful not to use a lot as that will cause the ice to melt very quickly.
- The ice will begin to melt.
- Spoon or drip colors on top of the shapes and watch them bleed and creep downward.
- Experiment with the amount of salt to make tunnels or pits on the shapes
- If you notice water accumulating on the bottom of the tray, remove it as it will cause the ice to melt faster and make the effects of the salt less obvious.
Salt changes the freezing temperature of water. When salt is added, water needs a lower temperature to solidify forming ice crystals. In this case, where salt touches the ice shape it begins to melt faster than in non-salt areas causing tunnels, pits and bubbles to form.
This experiment is more advanced and is probably best for older children. This requires the use of a stove. Be sure to keep small children away and always supervise them. Once materials are mixed do not touch the solution until it has cooled. Even though the sodium acetate trihydride is non-toxic be careful not to inhale fumes.
- About a cup of sodium acetate trihydride
- Although inexpensive and nontoxic this may not be readily available at stores and you may have to get it online.
- It's possible to make this yourself but usually yields inferior products so we will take the easy way.
- Medium or large pot that is steel or Pyrex, not copper!
- Glass container
- A stove with adequate ventilation
- Heat a small amount of water (1/4 cup) to nearly boiling in your container.
- Dissolve as much sodium acetate as you can by spooning into water.
- Save a little, raw sodium acetate for use later (there is a reason why).
- Continue to add small amounts of water. Just enough for the sodium acetate to dissolve.
- The less water used, the better the ice will be.
- You may not use the entire cup of sodium acetate
- Heat water higher till it is almost boiling.
- Stir constantly. You will know that dissolution is complete because a small amount of powder will be on the bottom of the pot.
- Once dissolved, slowly pour the solution into your glass container. Be careful that the undissolved powder in the pan does not transfer to the glass container.
- Refrigerate the solution for up to an hour then remove
- Put a very small amount of sodium acetate on the tip of the toothpick and touch it to the solution.
- Crystals should form instantly.
- If you carefully place a hand near the container you should feel heat radiating up to 130 degrees!
In short, during this process you have created a solution supersaturated with sodium acetate. Supersaturation in this solution means that it contains more dissolved material than can be dissolved under normal circumstances. After refrigerating, you have supercooled the solution. Supercooling is the process of reducing the temperature of a substance below the point at which it changes phase to a solid. As you may remember, phases of matter are gas, liquid, solid (and also plasma).
Supercooling the sodium acetate brings the liquid below the temperature it would normally freeze. But, because it is supersaturated it cannot crystallize and become ice. Introducing the solid sodium acetate provides a seed crystal, or nucleation center, for the rest of the liquid to organize around and begin to crystallize. While this substance is not water ice, it is a form of ice because it has solidified from a liquid. The heat is a form of exothermic reaction where the chemical energy in the sodium acetate is being released into the surrounding air.