Severe Weather- Snowflake Formation-Blizzard of Oz

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Objective

Students will observe how crystals form by conducting an investigation with 3 different kinds of salt.

Big Idea

How do ice crystals form?

Hook

5 minutes

While this lesson can stand alone, it does work well with the previous lesson about blizzards.  

I ring my chime to get the class’s attention.  I announce that we were about to begin the sixth Science lesson in our unit about severe weather.  I ask them to return to the carpet squares and ‘Show Five’.

We began our study on blizzards in the previous lesson.  Again, using the movie ‘Frozen’ as the jumping off point, I remind them of the part where Elsa builds the Ice Castle.  I ask them to curl up in a tight ball.  “Now, I want you to slowly- as slow as you can- stretch up like you’re a crystal, growing bigger.”  I let them explore this movement to act as a point of engagement before I transition them with the chime to the next step.

Large Group Instruction

10 minutes

Yesterday, we learned about blizzards.  What are some of the parts?”  “Ice!”  “Wind”  “Snow”.  “Right, remember snow is made up of ice crystals, kind of like the ones we studied yesterday.  We saw that they look different when they're bigger.  At it's tiniest point though- when it's just forming- every crystal has the same basic shape, with six sidesWe learned this shape in our lesson on bee colonies.  Anyone remember it?”  “Hexagon!”  “Right again.  These hexagon crystals form snowflakesThe amount of moisture and particles in the air, plus the temperature, decide how big the snowflake getsNo crystal- like no snowflake- is the same.  A unique environment makes sure that each snowflake crystal will develop differently.

 “It’s time for us to be scientists and conduct an experiment about crystals.  We are going to do a test and see what kind of solution- a mix of ingredients- will create the most observable crystal.  Why is it so important to learn about crystals?  Take a minute to talk about this with your partner.”  I give them minute to discuss this.  I’m looking for answers that talk about either snow, or crystal formation process..or both.  I get a suggestion, “If we know how snow starts, we can learn how bad it will be.”  “Definitely.  The more we know about the weather, the better we can prepare for it.  Who’s ready to get started?”

 

Small Group Instruction

15 minutes

Materials:

• Salt Assortment (I used table, alum, and epsom.  Borax could work as well)

• Water (warm water works well to dissolve the salts)

• Black paper (cardboard or construction paper)

• Paint brushes

• Small containers or jars for the solution

I use a chime to dismiss them to their tables.  “We are going to conduct an experiment to see how crystals grow using three different kinds of salt.  We need three small jars, one for each kind of salt.  We’re going to use Epsom salts, table salt, and alum.  We will use these crystals to grow bigger crystals.”   

Procedure

1First, put in some of the each salt into its jar. 

2. Next, add some warm water to the jars and stir it around with a paint brush so it dissolves. 

3. Last, take the paint brush in each jar and use the solution to paint your initial- the first letter  of your name- on the black paper. Remember, keep each brush in it’s own jar or the solutions will mix and invalidate your results- they won’t count.   

I give these initial, simple steps while doing some vocabulary and concept enrichment so the students have context to better understand the upcoming process and results.  "After it dissolves, all the jars will look like plain water again.  So how will we know the difference between the solutions?”  “Write their name?”  “Good idea, let’s label the jars so we know what kinds of crystals we are growing.”  When possible, I like to stop at a point and encourage the students to "teach" me.  It encourages their autonomy and ultimately, makes my job easier.  

Before I continue, I pass out black construction paper that I tri-fold into thirds.  This makes it easier for the students to organize their experiment,  To further aid this organization, I labeled each section with the names of the salts (Epsom, Table, Alum).  I then pass out three baby food jars (one for each salt) with blank labels, a small container of each individual salts, and a spoon to each table.  “While you wait for me to come by with some water, add some salt- just one spoonful- inside each jar.  Accurate records are so important with experiments so make sure to write the name of the kind of salt on the side of the jar so you know which kind you are using to test.”  I walk through the class with a carafe of warm water and put some in each jar.  The warm water will help the salts dissolve better so I remind the students to be careful.  “Take turns with the brushes.  It won’t take long, so be sure to discuss your ideas- your prediction- about the things you think might happen while you are waiting.”  When possible, it's helpful to have a helper (adult or older student) to help with this step so the students remember to keep the brushes separate.  It really makes a difference with the result!  After everyone has a turn painting each salt solution, I ring the chime and ask the students to put the brushes in the sink, leave their papers on top of the tables, and come back to their carpet squares.  

 

Wrap Up

10 minutes

I ring the chime to wrap up this part of the lesson.  We sit back on our carpet squares.  “This is the hard part- we have to wait.  Patience is an important step in science experiments because you don’t always see results right away.  We’re going to leave the papers on the tables for a few hours and check on them with our magnifying glasses a few times. When we get back from lunch, our solution should be dried.  Then, the fun part starts!  We get to watch our crystals grow and become bigger.  We’ll record the results on our data sheets from yesterday and measure it against our original hypothesis.  Let the learning adventure begin!"

Later in the day, we go back to the tables to revisit the crystals and wrap up the last part of this lesson, as well as the previous one on Blizzards.  The students observe how the crystals on their paper grew.  After a few minutes, I pass out diagram recording sheets from the previous lesson.  The class uses magnifying glasses to observe the crystals more closely, adding diagrams on the bottom row of the recording sheet to show how their observations from the crystals in the photos compare to the actual crystals on their paper.  "What things did you notice that were the same or different?  Take a minute to share with a table partner."  I circulate to listen to a few comments.  "The alum crystal was smaller."  "The salt crystals were tinier."  Comparisons like this support the scientific idea that hypotheses don't always match the result, yet have the potential to be a valuable addition to the learning experience.   After a minute of sharing, I ring the chime to end the lesson here and ask the students to put both papers away in their bags before they return to their carpets squares.