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“Sublimation Station: Discovering Gases with Museum of Discovery – Blueberry’s Clubhouse”

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Solids, liquids and gases … oh, my! You’re probably familiar with these natural states of matter (plasma is the lesser known state.) Matter can change from one state to another. For example, when the temperature of water is lowered to 32 degrees Fahrenheit, it changes from a liquid to a solid. This is called “freezing.” Today, your friends from Museum of Discovery are going to explore a phase change that occurs when a solid turns into a gas using a fun and hands-on bubble activity!

When Blueberry called on the Museum of Discovery to explain what makes balloons float, Educator Corrie turned to helium.

Helium is an element (number 2 on the Periodic Table) that is a gas in its natural state which moves freely, like air, and cannot be seen. Because helium is lighter than air, when balloons are filled with it, they float. Corrie also did a demonstration with liquid nitrogen, which is, as stated in its name, the liquid form of nitrogen. Like helium, nitrogen in its natural state, is a gas. Another gas you are probably familiar with is carbon dioxide. Each molecule of carbon dioxide consists of one atom of carbon and two atoms of oxygen (CO2.)

When carbon dioxide’s temperature is lowered to -109 degrees Fahrenheit, it freezes and becomes a solid. Its solid state is dry ice. When the temperature of ice (frozen water) is raised, its phase changes from a solid to a liquid. This phase change is called “melting.” So, when the temperature of dry ice (frozen carbon dioxide) is raised, it must melt too, right? Not so fast! When dry ice is introduced to a warmer temperature, instead of turning into a liquid, it immediately changes into a gas. This phase change is called “sublimation.”

Sublimation Activity

Getting started with sublimation

When you hold a chunk of dry ice using tongs in room temperature, you will notice that is looks like its smoking or fogging. That’s because as the carbon dioxide escapes, it is much colder than the surrounding air. The sudden drop in temperature causes water vapor in the air to condense into tiny droplets, forming fog.

When you place dry ice in warm water, it sublimates even faster. As the gas escapes, it rapidly expands within the water leading it to bubble. When the bubbles escape at the surface of the water, the warmer moist air condenses into lots of fog.

Now that you understand the process of sublimation, let’s have some fun with it, shall we?

Download a printable of the instructions here.

Here is what you will need:

  • 1 block of dry ice (Dry ice can typically be found in freezers near the check out of grocery stores. You must be at least 18 years of age to purchase.)
  • An adult present (Dry ice can be dangerous if not handled properly)
  • Safety googles
  • Tongs or a spoon
  • Nail
  • Any type of 16 oz – 32 oz plastic container with a plastic lid (Yogurt containers, margarine containers, Cool Whip containers, etc. will work. You can even use the plastic lemonade cups with the bendable straw you get at the fair.)
  • Plastic straw (the thicker the better) or a section of plastic or rubber hosing
  • Dish soap (Dawn works best)
  • Warm water
  • Hot glue gun
  • Funnel (optional if you are using hosing)
  • Directions:

  • Using the nail, puncture the middle top of the container’s lid. A nail works best because you need a circular hole (scissors will leave a slash instead of a hole.) Additionally, puncture the lid in another location of the lid (this will allow you to control the buildup and release of gas when making bubbles.)
  • Take the hosing or bendable portion of the straw (where you place your mouth) and stick it in the hole of the lid. Make sure that the bend of the straw remains exposed outside of the lid.
  • Glue around the straw or hose on the top of the lid and then around the bottom of the lid to secure it.
  • Mix one-part soap with three-parts warm water and pour in the container. You will want enough water to fill the container halfway.
  • Put on your eye protection.
  • Using tongs or a spoon, drop several quarter-sized chunks of dry ice in the container. Do not handle the dry ice with your bare hands.
  • What Happens?

    Using a straw for the sublimation activity

    You will soon see bubbles coming out of the straw. This happens because as the dry ice sublimates into carbon dioxide gas, it expands and fills the soapy water.

    Make Large Bubbles:

    If you are using a section of hosing or tubing, stick the small end of a funnel in the end of the hosing. As the gassy bubbles escape the funnel, they will grow larger around the exit of the funnel.

    LEARN MORE:

    Museum of Discovery 

    ”Blueberry’s Clubhouse”