an outdoors science problem solver

This activity comes from my workshop but I like it so much I wanted to share it. This isn’t mine, it’s pretty standard in all basic high school chemistry classes as an introduction activity.

Problem solving is a key skill in science. This activity is fun to solve and can be a work in progress over several days if need be. It also teaches some properties of chemistry.

 You will need to purchase iron shavings.I found some at this web site:

http://www.physlink.com/estore/cart/IronFilings.cfm for $2.

 In a large container, mix water, sand, lots of salt and the iron shavings.

The problem posed to your little scientists is how to separate them.

If you pour the water out, you loose the salt. If you separate them you’ll now have a salt-water mixture and a sand and iron mixture.

Have your child work their way through this in their mind and verbally with you before they jump in. Guide them along by asking then saying, “If you do that, you’ll end up with this…” until they feel like they’ve found a workable solution. Ask more leading questions for the younger ones.

The answer here is to separate them with a filter so you get the activity of filtration and end up with the salt water in a container and the leftover sand/iron mixture in another. This is the perfect time to talk about how the salt water is a solution and the sand/iron is a mixture. More info: http://www.edhelper.com/ReadingComprehension_27_39.html

Also, there is a great flow chart here:

http://www.chemistry.mtu.edu/pages/courses/ch1120-pcharles/Oxtoby_Ch01.pdf

 where your child can learn to go through and identify whether or not these are mixtures, compounds or solutions. Flow charts are very important in science.

 Next, separate the sand iron mixture with a magnet. Another problem will arise here. The sand sticks to the iron while it’s wet. So you can let them try, or ask what they think they need to do (let it dry). It will separate easily when dry. They learn about how sticky water is, surface tension is a good discussion here. Magnetism and iron and total cereal is a good lesson as a follow up here too.

Now you need to separate the chemical solution, salt water. This will be difficult for them and you may have to tell them the answer here. But first explain that when you heat a chemical solution, you usually cause a chemical reaction and many times, a vapor gas is given off. In this case, the salt will fall out of solution as the vapor (water) rises as it is heated. In English, boil it, the water evaporates leaving the salt behind.

  Make sure your child writes up a lab sheet on this. Also make sure they take notes about what they think will work and then the results they got. You can create a lab sheet for them by going step by step through this process and writing down good questions to ask along the way, print the flow chart, etc and use it too. I think you’ll find many possibilities here. I’d love to make one for you but the hand is still on the mend and typing this today will be all I can do. I will archive this on my site as well.