Introducing polymers and mix-linking within polymers by looking into making slime which demonstrates both liquid-like and solid-like conduct - the home referred to as viscoelasticity.
KS1: Sc3 Materials as well as their Qualities, Altering Materials 2(a)
KS2: Sc3 Materials as well as their Qualities, Grouping and Classifying Materials. 1(e)
KS2: Sc3 Materials as well as their Qualities, Altering Materials 2(a) and (f)
Summary of KS3: Sc3 Materials as well as their Qualities, Altering Materials - Chemical Reactions. 2 (h)
Per group/pair/child (as appropriate):
- 1 plastic disposable cup that contains 20 ml of borax solution* (borax or hydrated sodium borate can be purchased as powder from chemists/supermarkets, it's a soap)
- 1 plastic disposable cup that contains 20 ml of PVA glue solution*
- 1 wooden lolly stick for stirring
- 1 plastic dropper for that borax solution
- food colouring/glitter - optional
- clingfilm to wrap slime to consider it home
- Results table [PDF version ] [Word version ]
*see below for the way to organize these solutions
SAFETY: Do this under adult supervision. Borax and PVA are unsafe within their concentrated forms to be used by children, although the diluted solutions used listed here are appropriate for kids to make use of with supervision. Neither Borax or PVA ought to be ingested, and subsequently the slime is inedible. The kids should wash their hands after making the slime and before eating or visiting the toilet. Any leftover solutions ought to be diluted further with water and washed lower the sink by a grownup.
Prepare ahead of time (by and adult):
Prepare the borax solution the following: look for a container which could hold enough water for the quantity of slime to make (20ml each). Fill using the appropriate quantity of water and gradually add borax powder just a little at any given time, stirring until forget about dissolves.
Prepare the PVA glue solution: look for a container which could hold enough water for the quantity of slime to make. Calculate just how much option would be needed (20ml each). Mix half PVA glue and half water to achieve the prospective amount. Stir until a uniform consistency is arrived at.
2 cups are essential per group/pair/child. Pour 20 ml of borax solution into single serving - labeled borax, and pour 20ml of PVA solution in to the other cup - labeled PVA. Repeat til you have enough for everybody.
Children ought to be made away from the safety aspects about not consuming any solutions and never eating the resulting slime. Also, help remind them that you should wash their hands later on.
Go ahead and take PVA solution. A couple of drops of food colouring/glitter may be included to it at this time to help make the finished slime more interesting to check out. Mix using the wooden stirrer.
Give a couple of drops of borax solution at any given time using the dropper and stir using the wooden stick.
Continue adding the borax solution in drops until there's no liquid left and just slime remains. At this time the slime won't keep to the container.
Take away the slime in the cup and knead it by hands.
Permit the children to research the qualities from the slime. The outcomes table may help focus the analysis.
Wrap the slime in cling film when finished to avoid it becoming dry. The kids may take it home.
Discuss the obvervations with all of those other class.
Polymers are lengthy chains of molecules and they may be mix-linked, joining several chains together. This can alter the qualities from the polymer.
PVA is really a polymer polyvinyl alcohol.
When borax is put into PVA it leads to a reaction in which the PVA chains mix-link, or join together in places.
This will make the PVA less runny because the PVA chains can't easily slide past one another anymore.
If more borax is added, more PVA chains join together right up until the slime is created and also the PVA looks a lot more like a good.
The slime has completely different qualities based on that which you do in order to it it's viscoelastic.
It may be squishy (viscous conduct) or bouncy (elastic conduct).
If one makes a ball in the slime and drop it up for grabs, it'll bounce. The power from bouncing spreads through all of the chains that are became a member of together and may not disseminate within the time that it requires to bounce.
Should you put the slime up for grabs, it's time for you to gradually disseminate, much like a liquid. It's include a container (e.g. the cup) it'll spread and be exactly the same shape because the container.
- ‘Silly Putty’ may be the commercially accessible form of the slime made here. There's also several things you can test by using it because it holds its shape better.
- Make two sausages from the silly putty. Pull one apart gradually, and pull another apart rapidly. What's the difference? Consider what could be happening.
- If left overnight the silly putty will disseminate such as the home-made slime.
- The slime could be stored for a few days before it gets dry it ought to then be tossed away. It'll last longest should you ensure that it stays within an airtight container within the fridge.
- If left on clothes, carpets etc, leave to dry after which scrape them back. Any residue could be washed with tepid to warm water because the clime is water soluble. But it's best to avert this happening to begin with
WEB LINKS:
Homemade Slime
An alternate recepie in the Mad Sci Network, Washington College School Of Medicine, USA
Science in the shops - Let us get Physical!
Another slime recipe in the Department of Chemistry, College of You are able to, United kingdom
How come rubber stretch?
Details about polymer chains, their conduct and mix-linking, in the Polymer Science Learning Center, College of Southern Mississipi, USA.