I’m sure this is something we have all experienced before- you go outside and find a tool or other metal item completely discolored. You may already know, this discoloration is called rust. We typically expect something to take weeks or months to rust, but today I am going to show you a way you can rust a nail in just seconds. Want to see how it works, and how you can try this at home? Watch the video below to learn more.
Materials to Collect
- An iron nail (Make sure it’s not galvanized)
- A plastic or glass container that is large enough to hold your nail & all of the liquid ingredients. *Do not use a metal container or it might rust too*
- 8 teaspoons hydrogen peroxide (3%) (you can pick this up at any store where they sell first aid supplies)
- 1 teaspoon distilled white vinegar
- Table salt
- Safety glasses or goggles to protect your eyes
- A pair of gloves
Try it Out! (with adult supervision)
**Before doing this experiment, it is very important that all participants are wearing personal protective equipment (PPE): a pair of safety glasses or goggles and waterproof gloves. A pair of safety glasses or safety goggles is ALWAYS a good idea when working with liquids that could splash in your eyes. It is also a good idea to have a pair of gloves on hand because you don’t want to have prolonged skin contact once these chemicals are combined.**
Once you’ve collected all of your materials and have your personal protective equipment on, it’s time to start the science!
Step 1: Measure out your ingredients using the amounts listed in the materials section. If you need more solution, make sure you use 8 parts hydrogen peroxide to 1 part distilled vinegar as you measure out what you need. Then carefully combine the vinegar and hydrogen peroxide in your bowl.
**Once these liquids are combined, be careful not to touch the mixture. Putting on a pair of gloves when working with this solution is a great way to keep your hands safe.**
Step 2: Add enough salt to the mixture to saturate the solution (the same way you would make really salty water). Mix the solution together, you can use the nail if it is long enough, or you can use a wooden skewer. If you use the nail to stir, you may see a rust color and bubbles start to appear.
Step 3: Place your nail in the container. If you’re rusting more than one nail, choose a container large enough to hold all of the nails that you want to rust.
Step 4: Let the nail sit in the solution. Any part of the nail that is sitting in the solution will form rust on it. Keep an eye on your nail, and when you are happy with how rusty your nail has become you can carefully take it out of the solution.
Step 5: Let the nail air-dry. Wear gloves and carefully remove the nail from the solution. If you wipe down the nail you may lose some of the rust finish. Place it gently on a paper towel and let it air dry. In a few hours, your nail should look rusty and you can check it out a little closer. Be sure to safely drain your solution and dispose of your gloves.
What is the Science?
So what is rust anyway?
Rust forms on metals in a process called oxidation. Oxidation occurs when certain metals, like iron, are exposed to oxygen. For some metals this happens very quickly, and for others this process is a little slower. Metals that are protected by paint and other coatings will not rust because those coatings are protecting the metal from being exposed to oxygen. If some part of the coating is removed or damaged (like a scratch on a car, or paint on a bicycle wearing off) the metal will then be exposed to oxygen and the process of rusting can begin.
What is actually happening when rust forms?
In our experiment, mixing hydrogen peroxide (H2O2) and distilled vinegar together creates a small amount of something called peracetic acid. Acid is corrosive and can cause things like metal to break down. Hydrogen peroxide is made of hydrogen and oxygen, but it’s the oxygen that’s key to creating rust on metal.
The molecules of iron on the surface of the nail exchange atoms with the oxygen in the solution and produce a new substance. You guessed it–rust! (or iron oxide as scientists would call it!)
This whole process is helped along by the salt we added to the solution. Its job in this whole process is to act as an electrolyte which lowers the electrical resistance in the solution, helping the oxygen and the nail to trade atoms more easily.
**Atoms are the pieces that make up a molecule. These are super tiny and impossible to see with your own eyes, so scientists have to use very powerful equipment to see these tiny building blocks**
Why am I noticing so many changes?
Any time you see bubbling, fizzing, or a color change, that is a clue that you’re probably seeing a chemical reaction. This means that our iron is changing. Once the nail undergoes the process of rusting we can remove the rust from the nail, but the iron that turned to rust will never go back to being iron.
You might also notice the reaction getting warm. This particular chemical reaction is an exothermic reaction, meaning a chemical reaction that produces or gives off heat. This is one of the reasons we want to be sure to use proper tools and safety equipment throughout the entire experiment. If the nail is too warm for you to comfortably touch, use a kitchen utensil like tongs to remove your nail, or pot holders to safely relocate your container.
Ask Your Young Scientists
As you begin combining ingredients to make your solution, ask:
- What do you notice happening?
- They may see and hear some fizzing, some bubbling, the salt disappearing (dissolving) into the mixture, and they may notice that the mixture is clear but gets cloudy as the salt is added
Once the nail is in the solution, ask your scientists:
- What do you notice happening now?
- They may see and hear more fizzing or bubbling, the color changing, they may notice that the container feels a little warmer after a few minutes, or even see rust beginning to form on the nail
- What do you wonder about the things you are noticing?
- Your scientist may wonder why the color of the solution is changing, why it is bubbling, they may wonder why the solution has a different smell. They might wonder what rust actually is.
Once the nail is out and dry, ask your scientist to make a few comparisons between a rusty nail and a non-rusty nail.
- What things are different?
- What things stayed the same?
More to Explore
The amount of time you leave the nail sitting in the solution will determine how rusty your nail gets. If you only want a little bit of rust, try taking your nail out after a few minutes. If you want a really rusty nail, try leaving your nail in the solution all day, or maybe longer. You can leave the nail in the solution for as long as you want, but keep in mind that the container may get very warm if the nail rusts for an extended period of time.
Try this same investigation again but with a twist. Either use another nail or wipe off the nail you just used with a paper towel. Before you put the nail into the solution try covering it in petroleum jelly. Will it still rust? Let’s find out!
This content was made possible in part by the Institute of Museum and Library Services.
We want to see what you try at home. Share your experiments with us on social media by using the #ScienceAtPlay and tagging @CTScienceCenter.
Nick Villagra is a STEM Educator at the Connecticut Science Center, responsible for developing and delivering science experiences, including classroom lab programs, stage shows, and vacation camps. Nick holds a Bachelor’s of Science in Engineering from Swarthmore College. and has been a speaker at the New England Museum Association conference. Always looking to put a unique stamp on the Science Center’s offerings, Nick enjoys incorporating custom-designed 3D printed materials for students to interact with.