Liquid Nitrogen Fun!
Recommended Ages: Later Elementary, Middle School, High School
NOTE: This is really a Wandering Wizard activity, since it requires
special materials. We include it as a lesson due to popular demand but,
if you find liquid nitrogen to try it yourself, BE CAREFUL!
Try looking
in the Yellow Pages or similar references under “Gas - Industrial
& Medical.”
Guiding Questions:
- What is liquid
nitrogen?
- How do different materials behave under extremely cold
temperatures?
Objectives
Concepts:
- Liquid nitrogen is made from nitrogen gas.
Principles:
- A gas can be cooled and pressurized to form a liquid.
- A liquid can be warmed to form a gas.
- Nitrogen gas can be pressurized and cooled down to make “liquid
nitrogen.”
- Things dipped in liquid nitrogen become very cold.
- Cold and brittle material often shatters if “smashed”
or pressured.
- Some materials get stronger when cold; some materials get brittle.
Facts:
- You can see evidence of the cold nature of liquid nitrogen by observing
formation of ice crystals and “feeling cold.”
- As liquid nitrogen is exposed to the air, it warms up and we can see its
transition from a liquid to a gas.
- Things dipped in liquid nitrogen get VERY cold!
Skills
- Hypothesizing
- Observing
- Noting Cause-and-Effect Relationships
- Drawing Conclusions
Materials
Note: Some of these are specialized materials.
- Copper Pennies (post-1985)
- Balloon
- Banana
- Mixing Bowl
- Dry Ice
- Flower
- Goggles
- Hammer, nails and wood board
- Ice Cream Mix - Here’s one recipe
- Liquid Nitrogen
- Strong Mixing Spoon
- Tongs
- Gloves
- Water
- Whatever else you can think of to freeze and smash
Room Preparation
Set up chairs and desks in a semi circle so that all students can see the
demonstration.
Safety Precautions
Need to be careful when handling nitrogen and extremely cold materials,
which can cause
frostbite or damage eyes. Also, be sure that everyone is wearing goggles to
protect their eyes from flying pieces when smashing things. Keep faces away
from bowls of nitrogen, which poses a suffocation hazard due to its oxygen
displacement characteristics.
Procedures and Activity
INTRODUCTION
- Understanding liquids and gases
- What is a liquid?
Share examples like water, milk and soda. All are free flowing.
They have a definite volume. They take the shape of their containers.
- What is a gas?
Share ideas including oxygen, nitrogen, and carbon monoxide.
Gases have no definite shape or definite volume.
- What is liquid nitrogen?
Liquid nitrogen is made from cooling and pressurizing nitrogen
gas.
- Properties of liquid nitrogen
- All materials have properties—their own traits and
characteristics.
- Pour some liquid nitrogen into a mixing bowl. What properties
do we see?
- Cold
- “Smokes”
- Visible Liquid
- Seems to Disappear
- Can we see liquid nitrogen turning into a gas? What is
happening?
The liquid warms up and becomes a gas we cannot see. Pour
some more liquid nitrogen into the bowl and watch the
process happen. The liquid seems to disappear.
- What happens when materials get very cold?
Liquid nitrogen is very cold. If we pour it over things
or dip things into it, they get cold. See what happens
as we do “Smashing Experiments.”
ACTIVITY
Smashing Experiments
Smashing things is the first phase. Dip various things into liquid
nitrogen until frozen and see what happens to them. Many materials will
become brittle when cold. Others will get stronger when cold.
- Flowers will crumble in your hands.
- Freeze a copper penny for a good long time, then smash it with a hammer
and watch it shatter into pieces.
- Freeze a banana and then hammer a nail into a board with it.
Why do some things get brittle while others, like the banana, seem to
get stronger?
Other Experiments
- Take out a piece of dry ice and knock it around on the floor or table
top. Why does it glide so easily?
- Put a piece of dry ice into a rubber glove and seal it. What happens
and why? Now take the same glove and put it over a container of liquid
nitrogen. What happens now?
- Put a piece of dry ice into a glass of water. Notice how
it looks like a drink from a horror film. When the dry ice is gone,
drink the water. What does it taste like? Why?
- Blow up a balloon and put it over the container holding the dry
ice. Or you can shove the balloon into a container of liquid
nitrogen. What happens? Why?
Making Ice Cream
| The Process |
A Simple Recipe |
| Put the ice cream mix into a bowl, pour in some
liquid nitrogen, and stir. |
2 cups whipping cream |
| Continue stirring and adding liquid nitrogen until the mixture
is thick. |
2 cups light cream |
| Why do you need to keep stirring? |
4-8 tsp vanilla flavoring |
| Eat the resulting ice cream. |
1 cup sugar |
Closing - Original Questions
- Ask again:
- What is liquid nitrogen?
- How do different materials behave under extremely cold
temperatures?
Evaluation
Ask students to describe liquid-to-gas transitions and gas-to-liquid
transitions. Have students share what they observed and learned about liquid
nitrogen and materials that become very cold. Review what they observed from
smashing things, doing activities and making ice cream. Listen for evidence
that they understand the effect of cold temperature on materials.
Extension Ideas
Explore the properties of liquid nitrogen by conducting more experiments and
researching to learn about pressure versus temperature relationships, liquid
to gas transitions, and insulating properties of gas.
Careers Related to Lesson Topic
- Physicist
- Chemist
- Tour -
U of M Chemistry Department
- Wizard - Whiz
Bang Chemistry
- Chemical Engineer
- Tour -
U of M Chemical Engineering
- Mad Scientist!
Prerequisite Vocabulary
- Gas
- A fluid with no shape or volume that can expand indefinitely
- Liquid
- Something that is free flowing, takes the shape of its container and
has a definite volume
- Nitrogen
- A colorless, tasteless, odorless, gas element found in our
atmosphere
- Properties
- The particular characteristics or traits of something
Let us know what you think! E-mail our webmaster
Last amended 29 Sep 03