Thursday, January 24, 2013

Fossils

Here's a lesson I did with 3rd graders over fossils:

First, we looked at pictures of fossils. I created a quick matching game where students were asked to match the picture of the fossil with a picture of the organism that created the fossil print. We talked about how fossils form and why they're important.

Next, I passed out a bag of random objects. Most were rough seashells, but some were starfish, rocks, leaves, etc. Students could choose whichever artifact they wanted.

While they were doing this, I mixed up a batch of "fossil dough." For a class of 24, here's the fossil dough recipe:

3 cups of salt* + 3 cups of flour + 5-ish tablespoons of used coffee grounds** + 1-ish cup of water***

*3 cups of salt is roughly the amount of salt in one of those large, generic salt containers from Walmart.
**The coffee grounds are just for coloring; they add an antique-looking effect that makes the fossils look more realistic. I just used however many tablespoons I wanted...I added until I thought it looked good.
***For this, the trick is to add water very slowly. Because you're using flour, you don't want to use TOO much water, or else the mixture will be more like cake dough and impossibly sticky! The salt helps take away some of the stickiness, but you DEFINITELY want to be careful of adding too much water. {Can you tell I'm speaking from experience here??} I think I added somewhere between 1-2 cups of water for 1 batch. I added it until the dough started to stick together and mixed it all around. As I handed each student their wad of dough, if I noticed any part of the batch was too dry and crumbly to stick together, I would add a smidge more water to help it. It's your call.

Each student got a small ball of dough and was instructed to roll it like a ball and then squish it like a hamburger patty. Students then pressed their artifact into the dough to try to create an imprint. I let students keep their fossils on a piece of tin foil with their name written at the bottom for the next couple of days, since it takes the dough a little while to dry out.

Here's an example of a great-looking fossil that one student made:



You could probably use a toothpick to poke a hole at the top and thread a piece of ribbon through it to make an ornament for Christmas, if that's your cup of tea. :)

**I won't be posting again until after Christmas break so that I can relax and spend time with my family and friends. I wish you and yours a very blessed and merry holiday!**


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