facebook
Why is an iceberg frozen but not the water below it | Fizzics Education

Welcome!

Have 10% off on us on your first purchase - Use code NOW10

					

Why is an Iceberg Frozen but not the water below?

Why is an Iceberg Frozen but not the water below?

Follow FizzicsEd 150 Science Experiments:

You will need:

  • Two balloons
  • Salt, funnel and a measuring spoon
  • 75mL of water per balloon
  • A freezer
  • A stopwatch

Copyright

Why is an iceberg frozen and not water below science experiment - materials needed
1 Why is an iceberg frozen and not water below science experiment - funnel in the balloon

Place a funnel into the mouth of the balloon and add at least 1 tablespoon of salt into the
balloon.

2 Why is an iceberg frozen and not water below science experiment - adding salt to the balloon

Carefully measure 75mL of water pour it into the balloon, tie the balloon and shake to dissolve the salt.

Using the funnel, add 75mL of water to the other balloon and tie it.

3 Why is an iceberg frozen and not water below science experiment - starting the stopwatch

Place both balloons in the freezer and start the timer.

4 Why is an iceberg frozen and not water below science experiment - balloons in the freezer

Check the balloons on 10-minute intervals. Which freezes first – salt water or fresh water?

5 A man using a pipette to drop blue coloured water onto a taught strong that is suspended over a tray

Get the Unit of Work on Water Science here!

  • Explore the water cycle
  • Learn about cohesion, adhesion & capillary action
  • From water currents to floatation, join us to explore water science!

Includes cross-curricular teaching ideas, student quizzes, a sample marking rubric, scope & sequences & more

Orange read more button

6 LN2 sprinkler by Holly SciFest Africa Grahamstown March 2015
7 Teacher showing how to do an experiment outside to a group of kids.

Online courses for teachers & parents

– Help students learn how science really works

Orange read more button

Why Does This Happen?

Adding salt to water lowers its freezing point below 0o Celsius. As ice forms in polar regions, the salt within the forming ice is ejected into the surrounding water. This causes water below the ice to exist at sub-zero temperatures.

Also, water expands when it freezes – try measuring the diameter of the balloon with vernier callipers before freezing and afterwards once it has frozen > better than exploding cans in the freezer! Expanding causes the ice to be less dense than the surrounding liquid water, thereby the ice floats.

People use salt to melt ice on roads, an important safety concern for motorists.

Variables to test

More on variables here

  • What if you add sugar instead of salt?
  • Does vegetable oil do the same thing?

A man with a glove above a liquid nitrogen vapour cloud

Learn more!

Comments

2 thoughts on “Why is an Iceberg Frozen but not the water below?

    1. Hi Selina! This is dependent on the starting temperature of your water as well as which temperature your freezer is set at. Run this experiment whilst taking measurements on at least a 10-minute basis until one of the balloons has water inside that is completely frozen. Let us know your results!

Leave a Reply

Your email address will not be published. Required fields are marked *

This website uses cookies to improve user experience. By using our website you consent to all cookies in accordance with our Cookie Policy.