On the fourth day of Christmas Science, my mommy made with me...
Salt dough ornaments for our tree!
Some of our favorite chemistry activities have involved the preservation of materials and preventing bacterial growth. The pH level of an environment (whether it's acidic or basic) can have a huge impact on whether a home made decoration will last, or if it will wither away as a holiday buffet for the microbes all around. With this activity, we take a look at the chemistry of salt dough and make our own holiday ornaments!
SALT DOUGH ORNAMENTS
1. 1 cup of flour
2. 1/2 cup of salt
3. 1/2 cup of water
4. Rolling pin
5. Cookie cutters
6. Acrylic Paint
7. String or ribbon
1. Preheat oven to 250 degrees (F)
2. Mix all of your ingredients together in a bowl.
3. On a lightly floured surface, knead the dough until it becomes dry enough to roll, but still wet enough that it's pliable.
4. Once the dough is rolled, start using your cookie cutters! You can also use a paring knife to cut out your own designs. Get creative, you can make whatever you like!
5. Poke a hole in the top of your shapes, so that you can tie a ribbon through them later.
6. Put your salt dough shapes on an ungreased baking pan.
7. Bake in the oven for approximately 2 hours.
8. let them cool for 1/2 hour, then start decorating! We used acrylic paints for our ornaments, you can also use glitter glue or glitter paint for a more festive approach.
When we mix our flour with water, we notice that the flour starts to thicken and bind together. You may even see strands of this mixture as you're stirring! This sticky stringy substance is called gluten, and it forms when the added water washes away some of the other starches and enzymes, leaving gluten free to work its sticky magic!
The salt acts as a preservative, as it dehydrates materials by absorbing water. This makes the dough an inhospitable place for microbes to grow. Indeed, salt has long been used as a preservative throughout the ages, due to its ability to prohibit the growth of molds and bacteria! The hardened salt crystals, combined with the long strands of gluten, also allow for a more solid and cohesive structure in the dough!
This was a really fun and simple activity to combine a little bit of science with our holiday decorating. Now we have these adorable ornaments that we've made that will last for years to come!