Rocks and Minerals

Last night we did some investigating of rocks and minerals for Sarah, Plain and Tall. We borrowed the kit from a certain local university that has a few lending labs for teachers. If you are nearby to a college or university, I encourage you to check out what they might have to offer you as a homeschooler.

I started out by asking the kids how they might identify these rocks if they weren't sure what they were and that lead to talking about the different properties of the rocks and minerals that we use to categorize them- things like hardness, streak, color, chemical properties, etc. In a classroom, there are protocols for experiments running smoothly, but I'm working with three kids now so I let them have at it! Which means I let them take all the rocks out and just see what they could see after we talked about all the different properties. That's my kind of science and the kids loved it!

Here they are testing to see if the rock will react with 3% HCl (hydrochloric acid)- I know I should have a plastic tray but it was close to bedtime! This stuff is no worse than vinegar, but it brought back memories of spilling 6 molar HCl on my hand in college. That hurt! Results- the marble fizzed like crazy and that was a lot of fun. Check out the above picture- they wanted to see it happen a few times.

Yup- this one's magnetic! It's name? Magnetite- how about that?

Checking out the crystals and other properties on the surface of the rocks.

The Moh's hardness scale- the kids scratched glass microscope slides with each rock to see if it could make a mark in the glass. If so, then it was harder than 5.5 on the scale. If both got a mark it is around 5.5 on the scale and if it didn't, well it was less than 5.5 on the scale.

In the end, they only had to record data on two of the rocks. I'd have gone for all of them, but in the interest of time AND the fact that the pre-made data chart only had room for two- that's what we stuck with. This time of year the kit is busy otherwise I could have kept it for two weeks. I think we got a nice evening's work out of it though and I got to send it all back today instead of finding a place for it!

The kids were delighted to find another use for our magnet wands though...look out!