Breaking Geodes

There's nothing really informative in this post; just that geodes are cool and we think these have pretty crystals. We didn't find them ourselves (someday we will go to the Dugway Geode Beds, but our current vehicle doesn't facilitate it)---we just bought them from Amazon. But by George they were fun to break!

For an activity that demonstrates how some geodes are formed, go here.

Making "hot ice" (sodium acetate) crystals

Before we talked about rocks we talked about minerals, and when you are talking about minerals you have to talk about crystallization. I had seen a photo tutorial on how to make "hot ice" (the stuff that comes in those little hand-warmer packs; you break a disc inside and the whole packet crystallizes and turns warm) and it looked pretty simple, so I thought we'd try it. Then I read a couple other tutorials and all of a sudden it sounded like it wasn't simple at all, in fact it was fraught with uncertainty and peril, so I thought we wouldn't try it. We had several other crystallization activities, so I didn't really think it was necessary. . . and yet. I kept thinking about it, thinking how much the children would like it, IF we could get it to work.

Finally I found this video tutorial. He does a great job of making it seem possible, and giving you ideas for troubleshooting, but I also really appreciated how he said, "This is tricky to get right. You probably won't get it right the first couple times you try it." 

So, trying to set expectations as low as possible, I explained the demonstration to the children, and asked if they wanted to try it, knowing it might be frustrating and it might not work. They wanted to. So we began.

First you mix baking soda and vinegar. Carefully!---since you know what happens when those two mix.

You mix till all the baking soda is dissolved and the liquid is clear. Then you heat the solution over the stove.

He explains all this in the video, but basically you are trying to concentrate your vinegar---since household vinegar is quite weak; only 5% pure vinegar or so. It makes the house smell STRONGLY like vinegar, so open a window and don't stick your nose right down by the pot, or your eyes will be watering like crazy. This concentration process can take quite awhile. I think it was about a half hour for us. You are watching for a thin, slippery film to form on top of the liquid. Again, he explains this in detail in the video, but this (above) is about what it looks like. You need to take the solution off the heat as soon as you see this skin forming. And you can see the whitish powdery stuff on the side of the pot (upper right corner of this picture, in the shadow) which is sodium acetate crystals that have already formed.

I'll leave off the explanation of the chemistry involved in this reaction---I'd probably mangle it (find it in this video or this less-detailed one)---but suffice it to say, when you drop a crystal of the sodium acetate into the supersaturated sodium acetate solution, it initiates immediate nucleation and you can actually SEE the crystals form. It is really quite amazingly cool. And, probably thanks to our meticulous adherence to the directions (and our low expectations)---we actually got it to work! And we repeated the process several different times. Once you have the sodium acetate made, you can use it again and again (you just heat it to dissolve the crystals, then start the reaction over).

It was interesting, because sometimes our crystals looked more sharp and needle-like, like this^^

And other times they spread out in fan shapes, like this ^^

So, in spite of my fears that this would be one of those really frustrating and time-consuming demonstrations that never actually works---it wasn't! And it turned out to be one of the coolest things we've ever done. Watching the crystals spread through the solution, so orderly and yet so organic-seeming, and then reaching your hand in feeling the instant heat created by the chemical reaction, is incredible. We LOVED it. We wanted to see the reaction over and over again, and to show it to everyone we knew! And we will definitely be making this again (since after many uses, we have now thrown our sodium acetate away). 

Here are a couple videos---if you're only going to watch one, the first one is most impressive.

Hot ice crystallization---best version

Hot ice crystallization---slower, more needlelike crystals

Wonderstone Field Trip

Our first field trip during the rock unit was to Vernon, Utah to collect some wonderstone. I had never heard of the stuff before, but I read about it on the Utah Geological Survey (great website), and my friend Andrea's family was studying rocks too, so we went together.

The wonderstone (if I understand it right) is an igneous rock, specifically a kind of tuff---so it's made of volcanic ash which was compressed, and then water seeped in between the layers and left deposits of minerals behind, creating beautiful bands of color in the rock. You break open a rock and it's filled with circles and waves of maroon, orange, white, and yellow. It is seriously beautiful. I couldn't believe it was just lying around for us to collect! Amazing!

I would caution, if you are going there, that if you have just driven through Vernon as these directions describe, the dirt road you turn onto is BEFORE you reach the railroad tracks. It is right by mile-marker 17. These directions make it sound like you will cross the railroad tracks, but you will not---the turn is just before the tracks. We got going onto the wrong dirt road and drove several miles before realizing we were too far away from the mountains to be in the right place.

Gorgeous.

The site is clear out in the middle of nowhere, but at this time of year the dirt roads weren't bad and even the minivan was fine. I was glad to be with Andrea just in case we got a flat tire or something, but there were no mishaps. The area is just lovely. I love Utah; I think our desert is so often beautiful!

We were right up next to this nice hill, which of course the children had to conquer. They are so tiny in these pictures!

A lot of the rock is broken up in piles already,

but some of it is in rocky veins on the hillside that you can chip into with the rock hammer. So cool.

Elfish Emeline.

Everyone. In silhouette.

So pretty! I love the faraway mountains.

Patsy is such a good dog. Malachi loved playing "fetch" with her.

Junie and Harriet show off their finds

Yay, I have two babies! Marigold and Oskar.

I love the serious collecting going on here!

When we got home we put some of our wonderstone in the rock tumbler and it came out beautifully! I'll show that in another post.

Silver Lake with Laurisa

Silver Lake is so beautiful, and it was a perfect place to go with Laurisa and Jodie's families because it's level enough for Maggie's wheelchair! We had a nice time enjoying the not-quite-Fall day. We went earlier than our hike in this area last year, so the leaves weren't quite changing color yet, but the aspens definitely had a yellowish tint!

Blue jay!

A tiny yellow group of aspens up on the hill!

Rocks and Minerals Study Unit and Lesson Plan

For this unit, we found so many great resources on The Happy Scientist. I know I've mentioned him before but I just can't praise him enough. His videos are so informative, interesting, and even funny---but not in that annoying hyperactive/loud-music/in-your-face way that, say, Bill Nye videos are. For $20 a year to access all his videos and resources, I think it's a steal. Anyway, he has a whole unit on minerals and a whole unit on rocks, so we used several activities from those units as part of our studies. Fun.

We bought this box of rock and mineral specimens which I thought was really useful---it's so much easier to understand the characteristics of a rock or mineral when you can hold it in your hands and see it under a magnifying glass! The specimens are pretty good-sized and they come labeled with numbers, in case they get mixed up in the box.

We also bought Rock picks and goggles for our field trips. This was great because it made us feel like real rockhounders. The children LOVE wearing their goggles! And the picks did, in fact, come in very handy.

And, here's my Rock and Mineral Unit Pinterest board.

Making Fresh Mozzarella

I feel like I should make mozzarella a few more times before writing this post, because we're still so new at it! But I'm trying to get this Cheese Unit all written up before I forget everything, so I'm just going to plow ahead and show you what we did, failures and all.

So, we wanted to make some cheeses for this unit, of course, but I wanted to keep it pretty simple for our first attempts---nothing that needed aging, for example. (Maybe we'll try that someday!) We have made paneer before, but this time we made yogurt (technically a cheese), which is super easy, and ricotta, which is super easy, and then we moved on to mozzarella. Mozzarella is different because it's coagulated by rennet, so you can't just make it with lemon juice and milk like you can ricotta. A friend recommended this site, so I read a bunch of stuff there, and on other cheesemaking sites online, and finally settled on ordering this mozzarella kit. It has cheesecloth, a thermometer, rennet, citric acid, and cheese salt in it, and you can make a ton of cheese with it.

Here are the basic instructions: you heat a gallon of milk (to kill any bacteria, I assume) and then add part of a dissolved rennet tablet (or liquid rennet). You also add citric acid. Then you let it sit 5 minutes. It becomes stiff like pudding. You cut it into curds, then drain the whey and keep heating the curds to release more and more whey until you can stretch it. At the end you knead in some salt. And that's the whole process in a nutshell.

The first time we tried the mozzarella, we didn't get very good curds. They were small and ricotta-y, like this:

The instructions we had said that this might mean our milk was ultra-pasteurized (but it wasn't)---and it wouldn't work, so we should just start over.

We drained out the whey, stirred the curds together, and added salt, and used this as a cheese spread on crackers. It was quite tasty! But it was not really mozzarella.

Hmm. The instructions said that some milk is almost ultrapasteurized, and the high temperatures make it unsuitable for making cheese. Our milk was just regular milk from the BYU Creamery and it seemed like it should be okay, but we decided to try again with some goat milk we got from a goat dairy nearby.

We love visiting the goats. They are so cute and friendly! (At least they are friendly through the fence!) :)

Armed with goat milk, we tried again. This time the curds looked very promising. They were bigger and held together a little better than before:

But when the time came for stretching the cheese, again we couldn't get it to be stretchy. It was just in a soft lump in the bowl and when you tried to stretch it, it just broke apart softly, kind of like one of those soft cheese balls you serve with crackers. (Sorry I don't have a picture of that stage.)

Again, though, it tasted good, and this time I kind of patted some of the cheese onto pizza for our dinner.

You can see how it doesn't really hold together, and it's certainly not sliceable like regular fresh mozzarella. However, it melted beautifully, and it tasted really good on the pizza.

At this point, honestly, having already used two gallons of milk, I might have just given up on this. It was tasty, but it didn't seem worth all the work. But, then our friend Tami from Harmon's saved the day! She told us that they do mozzarella demonstrations on Saturdays at the store. But since we were going to be busy that Saturday, she said we could arrange to meet her at another time and she would show us how to stretch the mozzarella.

When we got there, Tami had hurt her wrist and couldn't handle the cheese! But she gave us a big container of curds, some instructions, and said we should go home and try it ourselves. Her instructions were a little different than our other ones. She said we should heat the cheese to 180 degrees instead of 135 before stretching it! So, we took the curds home, heated them, and . . .

Finally! They stretched. It was beautiful.

The fresh mozzarella is so delicious! It tastes amazing while it's still warm. We formed it into balls so we could slice it to eat with tomatoes and basil later. This ball is spreading out because it's still warm. I should have put it in cold water before it had time to settle like this.

Now, having had one success, I was motivated enough to try the whole thing one more time, from scratch. This time, like the first time, we used our regular grocery-store milk. We used 1/2 of a rennet tablet instead of 1/4.

After adding the rennet, the curds looked very nice.

We ladled them into a colander so the whey could drain, then put them into a plastic bowl.

Then we heated the bowl in the microwave. This time we kept heating it until it was 180 degrees, like we had with the Harmon's cheese. But still, the cheese was soft and lumpy and unconsolidated, just like it had been the first time. We were afraid we were going to be stuck with just a cheese "spread" again! But I had talked to a neighbor who had made cheese before, and her advice was: "It doesn't matter what the curds are like. Just keep heating them. When they are hot enough, keep stretching and it will work."

So, we persevered, heating them 30 seconds or a minute at a time in the microwave, stirring them with my hands, and then heating again. The curds got so hot that I had to put on cloth gloves (the stretchy kind you wear in the winter) beneath my rubber gloves so my hands wouldn't get burned! I just kept scooping the curds over each other in the bowl with my hands, trying to get them to form a ball. Suddenly they got shiny and I could tell they were starting to melt together! Then I could stretch them:

(cloth gloves underneath rubber gloves) You can see the kind of gritty-looking cheese on the wrists and arms of the yellow gloves? That is the cheese that stuck to me before it was hot enough. Once the curds were hot enough, they stuck together and cleaned off my gloves as I stretched the cheese.

And then we could form the cheese into nice little balls:

So! It was another success, and this mozzarella was just as delicious as the other. Hooray!

I think, now that I have seen this work, that if I had persisted longer with the first batch, I could have made that one work also. I just never got the curds hot enough and I wasn't patient enough with the kneading/stretching process. 

In short, here are my recommendations if you want to make this cheese. I really like the kit we got, and it will make you bunches of cheese. But, don't stop when the cheese is heated to 135---just keep heating and kneading, heating and kneading, until the cheese finally starts to be stretchable. Don't give up on it! And wear double gloves so you won't get burned. Since we have more rennet, next time I will double-glove Abe and Seb and let them do the stretching, but it's definitely too hot for really small kids to work with. However, little ones would probably love to watch and definitely have tastes of the warm cheese! It is SO delicious.