This scientific experiment will amaze children of all ages. I called it 'Thaw with salt' and it can help us introduce your sons and daughters, or your students, more advanced concepts about the states of the water. Next, I will tell you how to prepare this fun science activity and I offer you the scientific explanation so that you can pass it on to the children.
This activity can be focused on various age ranges, depending on the purpose we want to achieve, it can be aimed at: students of the first cycle of Early Childhood Education, specifically students between 2 and 3 and a half years approximately, students of Primary Education and Secondary Education .
- Silicone ice bucket
- Blue food coloring
- Felt fish
- Large tray or container
To make this activity more attractive for children, we can tell them a little story. Tell them that the fish and pompoms have been trapped in the ice and must be saved. How? With a little bit of salted water!
Let's see, first of all, how we can prepare this activity step by step:
1. Fill the silicone ice bucket with water. Remember not to completely fill every hole. Therefore, I recommend filling with the help of an eyedropper.
2. Then add in the gaps the felt fish and pompoms. If you can't buy felt fish, you can always make them yourself by drawing their silhouette on a piece of felt and cutting it out.
3. Now you have to put a drop (or less) of food coloring to some of the gaps.
4. Leave the ice bucket in the freezer for about 12-24 hours.
5. After this time, take out the ice cubes and put them on a surface such as a tray or some kind of container but that is deep enough to store the water that is thawing.
6. With the help of a dropper, take a few drops of water mixed with salt. We will see how each block of ice begins to unravel and thus we can rescue the frozen fish and pompoms.
This experiment will amaze the children and, the first thing they will want to know is ... And why is this happening? Here is the scientific explanation behind this experiment so that you can tell it to your children or students. Please note their age and understanding to adapt the explanation to your level.
Ice forms when the water reaches zero degrees (Celsius), but if the ice is sprinkled with water, it will begin to dissolve, and when this occurs (going from solid to liquid) the temperature will drop consecutively.
The salt is made up of Sodium and Chlorine (NaCl) and is called Sodium Chloride. This salt directly dissolves ice.
Ice does not melt, what melts is the dissolution of water and salt. Salt by itself would never lower the freezing point of water, which will remain below 0ºC, but the mixture of salt and water forms a solution where the freezing point is no longer at zero degrees, but at a lower temperature.
Salt can melt ice because the addition it contains makes it lower the freezing point of water. Since liquid water and ice water have a molecular equilibrium, and salt breaks it, lowering its temperature, preventing the freezing speed of water from being lower.
Depending on the purpose for which this activity is programmed, it may be directed to students of the following educational levels:
- Early Childhood Education of both the first and second cycles (0-6 years)
It can be performed in order to attract the curiosity, astonishment, and surprise of the little ones.
It is an activity that perfectly combines the visual and sensory to stimulate and develop the senses, through which you can play with new textures and temperatures.
In addition, if it is presented as something attractive, in which they must rescue (in this case fish and pompoms) by melting blocks of ice, they will concentrate even more on the activity and the success will be total.
- Primary Education, all cycles (6-12 years)
Within this stage we can develop this activity to explain in a more visual way the transition from the solid to the liquid state.
And in the second and third cycles of primary education, we can take advantage of this experiment to start them in the steps that must be taken when carrying out an experiment (hypothesis, procedure, conclusions ...).
- Secondary Education, all cycles (12-16 years)
In the first cycle it can be developed with the same purpose as in the previous cycles in Primary Education. And once they start the second cycle, it can be used in subjects such as chemistry to learn about different elements and their reactions.
A simple activity for all educational levels that will not leave your sons and daughters indifferent and that will also surprise adults.