Inside: Check out the Tin Hedgehog experiment, one of two experiments Mel Science provided me for review. Hedgehogs are adorable! Let’s find out what the tin version looks like. *disclosure: the following post contains affiliate links. If you click I may make a small commission but at no added cost to you.
The tin hedgehog experiment came in the the Tin kit Mel Science provided me for review (along with the Starter Kit described here). It was one of 2 experiments. Why did I choose this one first? Come on……hedgehogs are adorable. I had to find out what the tin version would look like.
Look at all of those spikes on this creature. Similar forms crop up in many things on this beautiful planet. These spiky outgrowths of the hedgehog serve as a mean of protection from predators. But we can see spiky phenomenon in the growth of crystal structures too. You’ve likely seen sugar and salt crystals magnified. These compounds prefer to form the more typical cubic crystal structure. The element tin on the other hand tends to form elegant needles when forming its crystal structure.
The Mel Science kit contained all the chemicals and apparatus to perform this experiment. The only pieces of equipment I needed from their starter kit was the safety goggles, the cell phone stand and the macro lens for my cell phone pictures.
Instructions for Performing the Tin Hedgehog Experiment
The pamphlet in the kit provides excellent instructions. However, it might be a good idea to read more on their website or through their App available in both iOS and Android versions. There are some hints and tricks included that may make your attempt more successful.
Make sure you ensure safety first. Both you (if you are helping a younger child) and your child need to wear both the safety goggles and the protective gloves. As well, perform this experiment on the tray provided in the starter kit. I found it difficult to remove the red cap after mixing the chemicals and some of the contents of the bottle did leak onto my gloves and onto the tray. I’m glad I was wearing those gloves.
Following the instructions as written in the pamphlet I was able to get great results. Check out the pictures below!
Here’s a closeup of the tin hedgehog taken with my Samsung Galaxy A8 using the macro lens given with the starter kit. You can clearly see the needle-like tin crystals which have formed on the zinc pellet. You can also see some bubbles that quickly formed after the pellet was dropped in. Because the pellet was spherical, so is the general shape of the tin hedgehog.
So how do these tin crystals form?
Let’s take the process step by step:
- in this experiment, the tin came in the form of a solid powder – tin(II) chloride
- tin does not dissolve well in water but does dissolve well in acids and bases.
- the tin is dissolved in a solution of sodium hydrogen sulfate – a weak acid
- SnCl2 + NaHSO4 → SnCl2 + NaHSO4
- after the zinc pellet is introduced to this acidic mixture you should immediately see bubbles
- those bubbles are the result of hydrogen gas being released due to the separation of hydrogen ions from the acid NaHSO4
- as well, there is a single displacement reaction where Zn, being more reactive than tin, combines with the chloride freeing the tin
- SnCl2 + NaHSO4 + Zn → ZnCl2 + Sn + NaSO4 + H+
- from the above you can see that after the zinc is introduced the reaction produces zinc chloride and free tin particles as well as free hydrogen which forms those bubbles
- tin particles do not settle randomly, they prefer a very specific pattern of joining together resulting in the formation of needle-like crystals
Some Cool Tin Facts
- number of protons in the nucleus (Atomic number): 50
- Atomic symbol (on the Periodic Table of Elements): Sn
- average mass of the atom (Atomic weight): 118.710
- Density: 7.287 grams per cubic centimeter
- Phase at room temperature: Solid
- Melting point: 449.47 degrees Fahrenheit (231.93 degrees Celsius)
- Boiling point: 4,715 F (2,602 C)
You can discover a lot of the above information using a periodic table
The needle-like crystals tin forms are highly organized. When tin is bent some of those crystals break creating a noise called the ‘tin cry’.
Check out this article by Live Science for some more cool facts about tin!
Mummy Can We Keep our Tin Hedgehog?
The answer to that question which your kids will ask is no! You can keep it for awhile if you don’t take it out of the solution. Those needles are very delicate. They won’t survive outside of the vial and even then they won’t survive forever in that vial either. I’ve taken a picture of my tin hedgehog in the vial 2 days after the experiment.
In the top photo you can see a hole or void in the ‘hedgehog’ where the zinc used to be. Most of the zinc has combined with the chloride. It seems the reactions continued without us watching. The bottom photo is from another angle. The tin crystals are losing their lustre.
I’ll keep mine for awhile and see what happens. But it won’t be as pretty as it was minutes after it formed. Our tin hedgehog is a short-lived pleasure unfortunately. Take lots of pictures right away with your kiddos so they can remember their shiny, spiky, little friend!
If you liked this experiment, check out my review of Mel Science here. If you liked what you saw and are super pumped about getting kits delivered right to your door with more amazing chemistry then click the link below to find out how from the makers of Mel Science.