I am a child therapist and this is essentially a "Calm Bottle" (see here) with a Christmas twist.

Supplies

Jar (I chose a round plastic jar from the Dollar Store)
Clear glue (or glitter glue)
White and silver glitter (fine and regular grain)
Hot glue gun
Christmas miniatures
Water
Super glue

Step 1: Create Snow Scene

Use hot glue to secure the christmas miniatures to the inside of the lid of the jar. Make sure that nothing interferes with the grooves or it will not close fully. I glued glitter to the bottom.

Step 2: Prepare Snow Globe

Making a Calm Bottle (clear glue): Fill the bottle 3/4 of the way full with water. Then add the glue (and shake) and glitter (and shake). I use a funnel for the glitter. The more glue you use, the longer it will take the glitter to fall. I usually use the whole bottle.
Making a Calm Bottle (glitter glue): Instead of clear glue you can use glitter glue. If you go this rout then mix the glitter glue in a bowl with very hot water (I boil the water) before adding it to the bottle. If the water is not hot enough then the glue will clump up and not work.

Step 3: Finish Snow Globe

Put the lid on the jar and superglue shut. This can be a fun decoration or used as a sensory relaxer to aid in emotional regulation.

Using a Calm Bottle: If you are making this with a client I suggest making it with them, rather than for them. It is fun to make, they can personalize it, it will mean more to them and they will be much more likely to use it. When your client becomes upset, angry, frustrated, anxious, etc., direct them to shake the bottle vigorously as long as they want as an expressive/physical release activity. When they are finished they set the bottle down and watch the glitter fall as they use their favorite coping tool and/or deep breathing exercise (how to teach deep breathing can be found here.)
Other uses: This is a common coping tool used for people who self-harm and is easily adaptable to many clinical issues. I have also used this as a coping tool + timer for kids who are transitioning into sleeping in their own bed or have trouble focusing and are taking long breaks during homework. It is a highly adaptable to numerous therapeutic goals. You can also make these just because they are awesome and fun to make, or as an art project :)