Christmas Science: Studying Snowflakes

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Ideas and activities based on snowflakes for the science classroom at Christmas

In the run up to the Christmas holidays you may wish to plan a festive science lesson, or two, for your classes. Here we present a couple of ideas with a snowflake-based theme, which are not only fun but teach some objectives from the new KS3 science PoS as well!

 

Why do snowflakes have six sides?

PoS statement: the differences in arrangements, in motion and in closeness of particles explaining changes of state, shape and density, the anomaly of ice-water transition.

 

You can start of by showing the class some images of snowflakes and video clips of them being formed. Use this as a novel way of explaining what happens when water freezes.

This video explains the science of snowflakes

 

Give pairs of students some molymods and ask them to make water molecules from them. Then see if they can arrange the water molecules to form ice. They should see that 6 molecules arrange neatly to form hexagonal shaped crystals.

For some KS3 classes, using Molymod kits may not provide a way of easily representing the H-bonds. This may be a little advanced for some classes as it not only requires thinking about  bonds but also then H-bonds. However, there are alternatives – if you’re feeling truly festive, why not get the students to make an ice molecule from midget gem sweets and cocktail sticks!

 

Chromatography snowflakes

PoS statement: simple techniques for separating mixtures: filtration, evaporation, distillation and chromatography

Get your classes to use chromatography to make colourful snowflakes to decorate the walls with.

  • To do this, give each students a circle of filter paper. They can fold it to make a scientifically-correct six-sided snowflake by following the instructions below. The dotted lines show where to fold.

  • Instructions for snowflake making

When they have folded the paper, ask them to cut some shapes into the triangle but make sure they don’t unfold the triangle.

  • Secure the shape with a paperclip at the top.
  • Add one or two dots of ink from coloured felt-tip pens about 1 cm away from the pointy end of the triangle.
  • Add some water to a beaker.
  • Thread some string through the top of the paperclip and place the tip of the triangle into the water (make sure the surface of the water is below the pen dots). Secure the string to the sides of the beaker with sticky tape so the triangle is held in position.
  • Leave until the water level has reached the top of the triangle.
  • Remove from the water and leave to dry overnight. Then remove the paperclip to reveal the beautiful snowflake.

 

 

 

 

Questions to ask the class

What type of separation technique are we using here?

What colour pigments were in the pens you used? How can you tell?

How does chromatography work?

How is chromatography used? (not normally for making Christmas decorations!)

 

 

 

Further Festive Science

Ever wondered where the bang comes from when you pull a cracker? Wonder no more by reading the article Christmas Science – The chemistry behind how Christmas crackers work.