Atmospheric Science – Part 3 – Solar Science

It has become a bit of a tradition for us to open the school year with a solar bag experiment.

Unfurling the Solar Bag


The solar bag is rather like a very thin black garbage bag only much much longer.

Solar Bag Filled


Once the bag is filled we tie it off and add a string.



Then we wait a few minutes for the air in the bag to heat up.  This year we had a nice conversation about radiant energy and convection while we waited.  We were also careful to observe that we could visibly see the bag had expanded.

Solar Bag in Flight

Eventually the bag was floating high in the sky.

You might notice a lot of clouds in the pictures.  The clouds caused a lot of rise and fall of the solar bag.  In past years, we have done the experiment on clear sunny mornings.  Clear sunny days are certainly best for having the bag flying for a long time, but the cloudy day really illustrated the importance of radiant energy from the sun.

We sourced our bag from Steve Spangler Science. (not an affiliate link)  If you choose to do this experiment make sure to choose a large grassy field and bring along transparent tape and scissors.

Hope you are having a great school year!

Atmospheric Science – Part 2

We are continuing our study of atmospheric science using lesson plans from UCAR with our own twist.  The activity today closely followed Introduction to the Atmosphere – Activity 3.  

Today’s activity was short, but packed with important concepts.

First we watched the following short videos from the Canadian Museum of Nature:

Part 1

Part 2

I emphasized to the boys that not all molecules are polar.  The polarity of water gives it properties that are important.  The polarity is introduced due to an uneven sharing of the electrons that create the bond between hydrogen and oxygen.

After viewing the videos,  we used paper plates and M&Ms to make models of water in it’s solid, liquid and gas states.


C chose to use single M&Ms to represent each water molecule.  This representation allowed us to shake the plate rapidly to represent gas molecules and more slowly when representing molecules in the liquid state.  He glued the molecules to the plate when representing ice and drew in the hydrogen bonds.

We briefly discussed that it is a combination of pressure AND temperature that effect the state of matter, but for our purposes we would be discussing water at a constant atmospheric pressure.  We also reviewed the temperatures at which state changes begin to occur in both Celsius and Fahrenheit at atmospheric pressure.



E chose to emphasize the  H2O structure of water.  The disadvantage was we couldn’t shake the gas and liquid plates, but we were more clearly able to see the need to line up the hydrogens facing the oxygen in the solid state.

Both boys used a roughly equivalent number of molecules in their solid and liquid representations.  We ended up moving a couple of molecules from solid over to liquid to emphasize that ice is less dense than water, which they knew but just didn’t think to count the number of molecules in each plate.

The shape of the arrangement and hydrogen bonds didn’t turn out exactly right in the models, but they did understand the concept of attraction between slight positive and negative charges that are easily overcome at higher temperatures (faster vibration).

Between the videos and the models the boys were able to clearly understand why ice is less dense than water and why that is a “special” case.  They were also able to grasp that hydrogen bonding between molecules is a much weaker force than the sharing of electrons between atoms, yet the hydrogen bonds are important in creating the structure of ice and causing it to float.

In addition to the lesson plan I think it is worth pondering some of the ways our world would be completely different if ice weren’t slightly less dense than water.  How would that impact life in ponds?  What about polar bears?  What about the planet as a whole?

Periodic Videos offers some thoughts on the importance of the density of ice:

Hope you are having a great day exploring the world around you!



Atmospheric Science – Part 1

This summer as I was trying to find a good answer to a particular science question,  I found a lesson plan that really did a great job answering the given question and giving a hands on activity that illustrated the concept well.  Then I realized the lesson plan was part of an entire set of Atmospheric Science lesson plans from the University Corporation for Atmospheric Research designed for middle school teachers.  The more of the plans and activities I read through the more I thought –  “These will be great to use with the boys! ”  There are lots of suggestions for hands on activities that will appeal to a variety of learning styles.

Today we started out with the boys telling me what they already knew about the atmosphere.  Then we read through about the first half of the Intro to the Atmosphere lesson.  After that we were ready to start with one of the suggested hands on activities.

Atmospheric Science - Sorting the M&Ms

What could be better for the first day of school than counting M&Ms?

Atmospheric Science - Representation of Earth's Atmosphere

First we counted out 78 Blue M&Ms to represent the amount of nitrogen in Earth’s atmosphere. Then 21 green M&Ms to represent oxygen and 1 brown piece to represent Argon.  There is a fleck of red in there somewhere to represent the 0.03% carbon dioxide.

Atmospheric Science - Earth, Venus, and Mars

Next we used the same color system to represent the make up of the atmospheres of Venus and Mars.

In addition to the planned topics, we had some great discussions about the contribution of plants to our environment, the water cycle, and ozone.  Then it was time for the best part:

Atmospheric Science - Eating the M&Ms

Eating some of the M&Ms!

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