Thursday, October 12, 2017

Experiments Which "Went Wrong" in Science Club Today

Today was a busy Science Club session!

My "littles" activity was to read a sweet vintage dinosaur book by Dahlov Ipcar called The Wonderful Egg.

We followed this book with three demonstrations:

  • making "naked eggs" -- Place a raw egg in a deep bowl and pour white vinegar over it until you've covered it up. Then watch as bubbles begin to form! The eggshell slowly dissolves overnight and you are left with a "naked egg." It is so much fun to play with.
  • rolling out my ball of finger knitted yarn in the yard to see the length of the Titanosaur -- Have your students work together to finger knit a long piece of yarn. Then wrap it around a meter stick until you've measured the length of it. Find a dinosaur whose length matches your yarn. Make a fact card about the dinosaur, read the fact card to the class, and then take them outside to unroll the ball of yarn and see how long that dinosaur was! Ours is 35 meters long.
  • exploring the evolutionary benefit of fins and webbed feet -- Fill a fishbowl, aquarium, or large deep bin with water. Have each child spread the fingers of one hand out, then run her hand through the water. Now have each child take a turn again, this time placing her hand in a plastic bag such as a newspaper sleeve. Open the fingers wide and let the plastic bag act like webbing. Run the hand through the water and feel how much more water is pushed aside!

After the younger group was done with their science time, the older group came in from playing outside and started their science time. Today's theme was, roughly, Science Club Wishlist. I've been asking students to keep the front page of their science notebook available for their science questions. Every few weeks they jot down science questions and I read over them and plan the next batch of activities. Most of the questions right now are about the human body, but there are a few odds and ends. One, for example, was "Where does wind come from?" Another child just wants to do sensory play and she keeps requesting Slime. I, for my part, have a few things I've seen (okay, yes, on Pinterest) that look cool to do. So I have my own wish list!

First Activity: Gummy Frankenworms

    This was a "fail" which simply means that it didn't work and we have to figure out why. There are no real mistakes in Science Club.
    We had a great discussion about why we think it didn't work... and decided that we have several variables which we could change.

    Baking Soda: The amount of baking soda we sprinkled on them could be wrong.

    Time: We could have left the worms in the baking soda solution for too long. (Natalie thinks the baking soda was too caustic and that it broke down the gummy worm structure.)

    Worms: I could have messed things up by buying the "fancy" organic gummy worms instead of the "regular" kind and perhaps the experiment required gummy worms with a different list of ingredients.

    Regardless of what went wrong, the simple fact is that they didn't do anything much. The bubbles formed but not enough for the worms to twitch and rise up through the vinegar, then dance, and then fall back down. To be honest, I was pretty disappointed because that activity had looked like a real winner. The photos of it online were pretty cool. But we will try it again next time!

Second Activity: What Makes Wind?

    For this I used two activities from the NEED EnergyWorks Student Guide (2009-2010 version... if you can't find it online, write to me and I'll send you the PDF). They were both in the Heat section (Exploring Heat 6 and Exploring Heat 7).

    For the first, we used two clear plastic cups, four marbles, hot water, ice water, and Dr. Ph. Martin's Hydrus Fine Art Watercolor, 1.0 oz, Cobalt Blue. Place four marbles in the bottom of one clear plastic cup. Pour hot water in the cup until it just covers the marbles. Place the second clear plastic cup inside the first so that it is resting on the marbles. The hot water should be touching the bottom of that cup. Pour ice water into the second cup. Wait 15 seconds. Working very carefully, place the eyedropper right at the water level so that you are not disturbing the water at all and add one drop of color. Let the students draw the movement of the color through the water. (This demonstration provides a lovely image of convection currents. Make sure that students understand that the currents were there already but the dye makes them visible. I have found that this particular dye works better than plain india ink. It seems to move and flow more slowly, giving them time to see what's happening.)

    For the second experiment, clean out your two handy dandy plastic cups and fill one with room temp water and the other with room temp sand. Place them in the house for 10 minutes with a thermometer in them, then record the temperature of both. Then place both outside in a sunny spot. Wait ten minutes and then record the temperature of both. Wait another ten minutes and then record the temperature of both again. How does this show where wind comes from? (Basically, the answer is that water and earth absorb and release heat differently and thus the temp is different above each of them. Warm air rises and cool air moves over to take the space it left. This is the same as what happened with the ink in the water; imagine if you could put a drop of ink in the air and watch it move. Think of it as air currents and water currents. This led to a discussion of how it never gets warm at the bottom of the ocean, and made me think of a good follow-up activity for next time: Ocean Zones in a Jar.)

    Obviously since I've given the overview of the experiments you could do them without the sheets from NEED but it's nice to have kids read supply lists and procedures and make hypotheses and record their data in neat data tables. I did have them write predications in their science journals as we went through the experiments, and draw the movement of the ink individually for the first experiment. But we used just one data table for the class for the second experiment. It was easy enough to record and share the data as a group.

Third Activity: Jack-o-Lantern Halloween Slime

    This was another "failure." Our recipe (here's a nice liquid starch slime recipe in printable PDF format) called for equal parts clear Elmer's glue, water, and liquid starch. You add the glitter or coloring after the glue and water have been mixed thoroughly and before the starch goes in. I could NOT find liquid starch in any store near me but I did find a non-aerosol spray starch. I figured that I could unscrew the lid and pour it in and it would be the same thing. NOPE.

    Again, there are several things which we can do here. We had a nice conversation about mixtures versus solutions (which was helpful for our next experiment, to follow). Our theory is that the starch has been thinned with water so that it could go through the spray nozzle without clogging it. That means that the ratio is off because there's too much extra water (we've already covered ratios with Oobleck). Option #1 is to leave our concoction out uncovered until the extra water evaporates off and we have slime. Option #2 is to make the recipe again leaving out the water and just mixing the glue with the liquid starch. We decided to try Option #2 in our next Science Club session. For the Gummy Frankenworms, we decided to retry this one as well with the cheaper gummy worms.

Fourth Activity: Separating Sand, Salt, and Iron Filings

    After the kids went outside to run around for ten minutes, we set up the final activity. I showed them my kitchen scale and how to place a small ramekin on it and zero it out. I poured 17 grams of salt in, then put the salt in a small mixing bowl. We zeroed out the scale again and I poured 30 grams of sand in the ramekin, then poured it into the mixing bowl with the salt. Last, we zeroed out the scale again and I poured 3 grams of iron filings into the ramekin, then poured it into the mixing bowl with the other two materials.

    We passed the bowl around and everyone got to stir it all together.

    Then I said to the children quite calmly, "Now we have to separate them back out again." We discussed how it was a mixture, not a solution, and how it should be possible to separate them. But how???

    I gave them 10 minutes to brainstorm in their science journals. I did show them a magnet and tell them that was a clue. But I didn't give any other hints besides asking them to consider in which ways salt and sand were different. We poured a small amount of each into bowls so they could compare the color (for those who thought we could separate by looking at them closely) and I let them pinch and feel each betwen their fingertips (for those who thought we could separate by feeling them carefully).

    This is one I can't wait to revisit next Science Club!

This post contains affiliate links to the materials I actually use for homeschooling. I hope you find them helpful. Thank you for your support!

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