How to Make an Easy 3 Ingredient Slime With Contact Lens Solution
Kids love playing with slime. The squishy slippery stretchy mixture provides them with a fantastic sensory experience, and it is fabulous fun. One of the best slime recipes involves using contact lens solution. Yep, contact lens solution! It’s easy to make and it doesn’t require Borax or liquid starch.
Why make slime?
There are a lot of good reasons to get busy and make homemade slime.
It is great for the development of gross and fine motor skills, as the muscles of the hands and fingers manipulate the slime into different shapes
Like most kitchen crafts it requires careful measurement of materials, a good way to introduce a little math into the day
For slime to form a chemical reaction must take place, so this is a great science activity
Turn this into a reading and comprehension activity and invite your kid to read the instructions and follow the steps.
How does it work? It’s all science!
School glue, such as Elmer’s Glue, is made up of polyvinyl alcohol (PVA) polymers. Very simply, a polymer is defined as two or more molecules joined together to form a chain, but those chains can be very long. Polymers can form a thick liquid like glue because the molecules in those long chains can easily pass by one another. How does the glue transform into slime? It needs an activator, like boric acid and sodium borate (found in Borax and particular brands of contact lens solution), to cause a chemical reaction to occur between the glue and borate ions to form a new substance. The activator also changes the position of the molecules cross-linking or bonding the chains together. When the chains are cross-linked, they can no longer pass by one another easily and that makes the slime stretchy.
This recipe works!
If you’ve tried to make slime in the past, you may have memories of producing nothing but unusable sticky gloop. But if you want a fast and failsafe recipe then this is for you! It has a simple ingredient list, can be made quickly and is super stretchy. If you want to jazz it up, then you can add food coloring or glitter.
What you need to know before you get started
Why contact lens solution?
Firstly, many slime recipes call for Borax and liquid starch, two products not readily available in all regions. Secondly, though you can use Borax it can cause skin irritation. A much gentler activator is contact lens solution provided it contains the boric acid and sodium borate necessary to create the required chemical reaction. We used the renu Bausch + Lomb Lens Solution and found that it did the job.
You may try replacing the contact lens solution with a saline solution, but make sure it does contain boric acid and sodium borate in the ingredients list. Bausch & Lomb Splash Saline Solution do list these ingredients but we have not tried this product to make slime.
Soap and slime
Soap can give slime an unpleasant ‘extra’ slimy feel. If your kid washes their hands before playing with the slime, make sure they thoroughly rinse and dry their hands.
Storing slime
Slime will last up to five days if stored in an airtight container.
Safety first
Science experiments always require adult supervision. Please keep the following safety guidelines in mind:
Adults should always be informed about the products to be used. Products can vary depending on your area and even between brands. Please, read all labels carefully.
Be cautious when substituting ingredients as changes may affect chemical reactions and alternatives may not be suitable for children. For example, not all glues are non-toxic and suitable for use by children.
Adults should be involved in the process of making slime. In science experiments, both ratios and process are critical to the success and safety of the outcome. If steps are missed, or incorrect ratios are added, the slime may fail, or the result may cause harm.
If any glue or contact lens solution is ingested, please seek medical attention immediately.
If you notice any skin irritation, itching or redness discontinue use immediately.
Slime should not be placed in the mouth or ingested.
Always wash your hands after playing with slime.
Play with slime in moderation. Slime should not be played with for an extended time.
How to make contact lens slime
This recipe will take about 5 minutes to make. Be sure you follow the instructions carefully as the correct ratios will produce the right consistency.
Elmer’s Glue (non-toxic and washable, white or clear) - 6 oz (180ml or ¾ cup)
Baking Soda (also known as bicarbonate soda) – ½ teaspoon
Contact Lens Solution – 1½ tablespoons
Water – ¼ cup (optional BUT helps make the slime more stretchy)
Liquid food coloring – a few drops (optional)
Glitter – optional
Step 1:
Add 6oz of glue to a bowl.
Step 2:
Add baking soda by sprinkling it over the glue and mix thoroughly.
Step 3:
At this point, if desired, add a few drops of liquid food coloring or glitter. Mix thoroughly.
Step 4:
Add the water if you want super stretchy slime. We added the water to this mixture.
Step 5:
Add the activator of contact lens solution a few drops at a time and start to mix thoroughly. As you slowly add the contact lens solution the mixture will start to pull into a ball.
It’s important to add this slowly to control the structure of the slime. If you add it all at once, the mixture will start to harden, and you will not be able to manipulate it to create stretchy slime. You may find that you do not need to add the entire 1½ tablespoons to get the right consistency, so take your time.
Step 6:
Take the slime from the bowl and start to knead it with your hands. It will be quite sticky at this point but the more you stretch and knead the less sticky it will be. If you are finding it is too sticky add a few drops of contact solution and continue to mix it in. Don’t add too much or the mixture will become too hard or begin to break.
Trouble shooting
If it’s too hard or it’s breaking then you’ve added too much of the activator. Try adding a little lotion or baby oil to your hands and begin to knead.
AND now you have slime!!
Extension Science Activity
Change the ratio – an observation experiment.
When creating a mixture, the amount of one ingredient compared to another makes a difference in the outcome. This is called a ratio. We use ratios to work out how much of one ingredient you need to add to your mixture so that it has the properties you want. For slime, we want just the right amount of stretchiness, so not enough glue or too much contact lens solution and you may not make the slime you wanted. You can change the properties of a mixture by varying the amount of each ingredient used to make them. Why not change the amounts of the ingredients in this slime recipe and see what happens? Encourage your kid to make a hypothesis about what they think might happen and write down their observations.
The final word
Slime is great fun! Make this simple contact lens slime recipe and encourage your kid to learn a bit about science along the way.