Saturday, March 16, 2013

STEM Themed Linky Party #4



STEM themed Linky Parties: 1st and 3rd Sat of each month: STEMmom.org

Welcome to the STEM Mom's fourth Linky Party! This linky party is open on Saturday February 16, 2013 and closes 8 days later, Saturday February 23, 2013.  The following week, I will choose two lucky winners who will be featured in a blog post at STEMmom.org, and will receive a special "STEM Mom Liked this Post" button that can be forever displayed on the winning post.  

In the spirit of STEM, any science, technology, engineering, or mathematics activities for ANY age are welcome to be entered in the STEM Mom Linkys. Note: Links that are not STEM related will be deleted.

However, special consideration (to be featured on my blog the following week) will be given to posts that:


  • Give detailed explanation of the activity so that others can do it with their students
  • Offer free handouts (if applicable)
  • Include math as a component to the science activity
  • Proudly display the "I linked up @ STEM Mom" button on the post they link up
  • Integrate multiple science content areas (for example: biology and chemistry or physics and earth science) 
  • Focus on engineering (the often forgotten vowel of STEM)
  • Integrate multiple science content areas (for example: biology and chemistry or physics and earth science) 
  • Include technology aspects into the other areas, science, engineering, and mathematics.
When you link up, grab a button and place it at the bottom of your post! Please be sure that you link to the specific post url, not your homepage. 

Thanks so much.  Looking forward seeing what you all have to share! If the linky is closed, check my linky page to see when the next party opens.

the STEM Mom





Friday, March 15, 2013

pH Baseline Reference -Cabbage Indicator


Although doing a pH lab seated at a table is hands-on, and might be considered "fun" (depending on the mood) we know it can help make the spectrum of pH more understandable. But don't be fooled; it isn't doing science, its learning science. Once students understand a bit about the pH spectrum, they should be encouraged to design an experiment to test the pH of substances for a real reason! Whether you use cabbage indicator solution, DIY pH papers, or store bought pH papers, it is a lot of fun to see how substances in the environment vary in their pH.

Using pH papers as data collection to DO real SCIENCE!: STEMmom.org
We decided to test area snowfall from different areas of our yard. We selected samples from snow piles under a tree, near our shed, and a water sample from a large puddle in our front yard.  

Boy collecting snow sample in order to test pH: STEMmom.org

We used a paper plate, divided into 4 quadrants and labeled A-D. The clipboard held the paper that we wrote down where the samples came from, and also held our paper plate in place (sort of....we're in the country, and its windy) so we could scoop snow or water samples using our plastic spoon.

 Boy collecting snow sample to test pH as a STEM lab: STEMmom.org

Boy collecting water sample to test pH in a STEM lab: STEMmom.org

Once we came inside, we used our DIY pH paper strips, to test our water/snow samples to see if their pH was different at all. We compared our pH papers to the pH baseline scale that we constructed on a previous day (free download at the end of this post) that showed the color variance of the full pH spectrum. 

Boy using pH paper to test snow samples in a STEM lab: STEMmom.org

I printed the baseline pH table on card stock and laminated it so the wet pH paper strips could be placed right on them for direct comparison.

Use a basline pH scale from STEMmom.org to do on-the-field pH testing

For our field science experiment, we found that all the snow and water samples were in the "normal" or "7" range. However, I have a feeling we will be packing our pH paper strips in our hiking bag this spring and summer for more STEM fun.  For the FREE download, visit my Teachers Pay Teachers Store.


This is a baseline pH scale students can make using cabbage as a pH indicator: They fill in the "color" row with crayons, and use this as their basline reference for all future pH test they make. Free download available via STEMmom.org

 

If you liked this lab be sure to visit my other posts on pH:


Using Cabbage Juice to make pH indicator solution
DIY pH Paper using Cabbage Juice and Coffee Filters



Keywords: free download, homeschool lab, on the go science, STEM lab, pH, free download, chemistry, field science, inquiry,



Wednesday, March 13, 2013

DIY pH Paper Tutorial

Cabbage Juice as an Indicator: An Update


Cabbage pH indicator solution and paper: STEMmom.org

I can't describe how tickled I am at how well the cabbage juice worked as a pH indicator. It was fun to make, and the results were visually stunning. (OK, my inner science geek is totally peeking through!) However, I have a confession and an update.  The confession is that cooking cabbage will stick up the room.  And the smell only gets worse the longer you store it! I've stored my juice in a plastic peanut butter jar, and the juice has wrecked havoc on the bottom of the plastic jar, as you can see from this photo, and started leaking the smelly juice. Therefore, I am warning you to store your cabbage juice in a glass container instead.

Don't store cabbage juice in plastic jars, it will "melt" it and then leak: STEMmom.org

I've transferred my cabbage juice from a plastic container to a glass one. But notice in 4 days time, it is no longer purple, but pink. Hummmm....

Store pH Cabbage Juice in glass containers: STEMmom.org

Here's my update.  After only four days, the cabbage juice has changed color from a deep purple, to a pink color, indicating that it is becoming more acidic. However, I ran my baseline test again, and it still works as an indicator.  Therefore, storage long-term is probably not the best idea.  If you want to use the cabbage juice indicator, you should mix it up only a day or so ahead of time, or better yet, have your (older) students make the solution the day they plan on using it. (I'll post a lab for older students later.)


Another solution to the liquid storage issue, is to use the cabbage juice to make your own pH paper. As usual, I took a lot of pictures, but it really is easy as just soaking coffee filters in cabbage juice.

Tutorial on making your own pH paper using cabbage juice and coffee filters: STEMmom.org

Materials Needed for Making Your Own pH Paper

  • 1/4-1/2 head of red cabbage
  • blender
  • rubber/latex/surgical gloves
  • boiling water
  • rubber spatula
  • coffee filters
  • shallow bowl or pan
  • clothes line and pins
  • scissors
  • paper envelope for storage of pH strips

 

Tutorial on How to Make Your Own pH Paper


The instructions for obtaining the cabbage juice is the same that I described in my previous tutorial on how to use cabbage juice as a pH indicator. The only difference is that you want the solution to be super concentrated. To extract as much as I could from this beautiful purple vegetable, I cut up about 1/4 head of cabbage and placed it in a blender. I only added enough water so the blender would chop it properly.

Blended cabbage bits for making DIY pH paper: STEMmom.org


Tuesday, March 12, 2013

Gumdrop-Toothpick Engineering Challenge

This is an engineering challenge idea that I’ve modified from one I found on Teacher’s Domain. My 5-year old son was up for the challenge, and I’ve also done the activity with science teachers at a professional development workshop. You’ll love this activity as part of an engineering unit, when you’re introducing shapes, or just for a fun Friday or rainy day activity.

Testing Gumdrop Structure Engineering Challenge: STEMmom.org

Marci saw my post about a collection of activities I did for a state science teacher workshop, and asked me to guest post at the Homeschool Scientist about the gumdrop engineering challenge. In the post, I give tips on how to approach the activity with varying levels of inquiry appropriate for any age, along with FREE Downloads that include two versions of student handouts. Head on over and take a look! I would love to know how your students enjoyed this activity!   

Testing Gumdrop Structure Engineering Challenge:Book on structure, Fail!: STEMmom.org

Wednesday, March 6, 2013

pH Cabbage indicator tutorial and labs

Cabbage Juice as a pH indicator: Tutorial and tips for pH labs from STEM Mom

Although pH paper won't break the bank, it is easy to make a pH indicator solution (or paper) from supplies you can get at your local grocery. What you need:

  • red cabbage
  • filter paper or coffee filters 
  • boiling water
  • pot
  • strainer

I've taken a lot of photos, because red cabbage is absolutely beautiful! But really, making the solution as easy as boiling a cabbage and using the water as the indicator! 

Steps to Make Cabbage Indicator Solution


Cut cabbage into small pieces: pH indicator lab from STEM Mom.or


  1. Dice 1/2-3/4 of a cabbage into small pieces and enjoy the beautiful color.  
Cut cabbage into small pieces: pH indicator lab from STEM Mom.or


2.  Boil water in the microwave or on the stove.
3.  Pour boiling water over the cut cabbage and allow to steep until room temperature.

Steep cabbage in boiling water to make pH indicator solution: STEM mom.org

Steep cabbage in boiling water to make pH indicator solution: STEM mom.org



4.  Strain cabbage through a strainer so only the purple liquid remains. You may chose to filter the cabbage/water solution through a coffee filter in addition to straining. 

Strain cabbage to isolate purple indicator water; from STEMmom.org


Strain cabbage to isolate purple indicator water; from STEMmom.org


5. Reserve the purple liquid for experimentation. I store my excess cabbage juice in an empty plastic peanut butter container with a tight lid. 


Labs Using Cabbage pH Indicator 


Its best to set students up to experience the whole pH spectrum. While you could TELL them about the differences between acids and bases, I believe its best to let them experience the color changes in an inquiry-based lab, and allow them ask questions naturally, so they actually want to know why there are differences. 

Therefore, I suggest providing students with the following materials to test and record:

  • lemon juice
  • white distilled vinegar
  • water
  • baking soda
  • washing soda (or ammonia) 

Boy testing pH of lemon using cabbage indicator; STEMmom.org

Start the laboratory experience by determining the scope of the pH scale. You do this by using the materials listed above.  

Pour the cooled cabbage indicator solution into test tubes or small jars. We used glass baby food jars which worked great because they don't tip easily, and any color change is easily noticeable. So we poured cabbage juice (which does have an odor you will notice) into each of the 5 jars. Then we created a data table that looked like this. However, I provide a free student lab sheet at the bottom of this post if you want something quick.

Entering data for pH lab using cabbage indicator: STEMmom.org

 
Since I am working with a five-year old, I made the table, and had colored pencils and crayons  available for him to use to record data.  He poured, squeezed, and dabbled the lemon juice, vinegar, water, baking soda, and washing soda, into the baby food jars one at a time and got amazingly different results; visible by stark color differences. 

Sunday, March 3, 2013

STEM Linky #2 Winner - Pinecone Study





We have a new blogger on the horizon, and I've decided to feature Rachel @ Momma Owl's Lab and her post, The Pine Cone Experiment. I'll let you go visit her post, for the details, but the kids make predictions about what happens when they put pine cones in water. Rachel does a great job of framing the science talk, providing extension activities, and even provides a table showing what science process skills are used in the activity. And you know I am ALL about process. So please, go take a look at her site, and be sure to welcome her to the blogging community by leaving a comment!  





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