Comparing the Accuracy of Liquid Measurement Tools

Blog, She Wrote: Comparing the Accuracy of Liquid Measurement Tools

Have you ever thought about how accurate your volumetric measuring tools are? How do you know your measuring cup is calibrated? Is it good science to use your kitchen tools for science? Today’s discussion is Comparing the Accuracy of Liquid Measuring Tools.

Are All Volumetric Measuring Tools the Same?

Blog, She Wrote: Comparing the Accuracy of Liquid Measurement Tools

The gold standard in measuring volume is the Volumetric Flask. It’s a laboratory flask which is calibrated precisely to a certain volume at a particular temperature. They come in various sizes from 1-10,000 mL of liquid. But, they are also expensive and they are typically not found in classroom labs or homes because neither work with extremely precise volumes of liquid.

So, what do we use instead? The rule of thumb is to use the graduated cylinder. With all the markings on the cylinder, it is considered more accurate than other volume measuring tools. But, is there a big difference? We decided to test them to see.

Tools for Measuring Volume

Blog, She Wrote: Comparing the Accuracy of Liquid Measurement Tools

What are some tools available for measuring volume?

  • Beakers- Are containers primarily used for mixing and heating. There are markings on them for measuring, but they are meant to be approximate.
  • Measuring Cups- The liquid measuring kitchen variety. We use Pyrex brand.
  • Erlenmeyer Flasks- These are wide bottomed but not circular with a neck that can use a stopper (with or without holes). It makes a good reaction vessel and allows a larger area for smaller volumes.
  • Florence Flask- This is a round bottomed flask used for boiling solutions.
  • Field Collecting Tubes- These are screw top collecting tubes which come in 15 mL or 50 mL and they are terrific for collecting aquatic specimens in the field. We use them during our entomology excursions.
  • Pipettes- Used for moving small volumes of water or removing liquid in small increments. I like the disposable kind because the cleaning is much easier!
  • Graduated Cylinder- Are used for measuring volumetric quantities. They range in size from 10- 1000 mL. If you are going to choose only one, the 100 mL size is a good one.

So, if you want to use something other than what’s found in your kitchen, where do you get them? We use Home Science Tools. We order some specialty items, like collecting tubes, from BioQuip. Just for fun, we also visited our local university’s chemistry supply room. Armed with gift money, our then 8 year old, took a trip with Dad to pick out his own glassware.

Testing the Accuracy of Volume Measuring Tools

Blog, She Wrote: Comparing the Accuracy of Liquid Measurement Tools

Since we used the graduated cylinder as our gold standard, we chose to determine the final volume in a graduated cylinder. Our procedure:

  • Choose a beaker, flask, or collecting tube and fill it with water to the highest marked volume in mL.
  • Record that volume in your data chart which will be labeled with the containers you are using.
  • Pour the contents of the first container into the appropriately (closest) sized graduated cylinder available.
  • Measure the volume of water in the graduated cylinder
  • Record the volume.
  • Repeat using various sized measurement tools.

How to Record Data When Doing a Science Exploration

Blog, She Wrote: Comparing the Accuracy of Liquid Measurement Tools

The data chart for recording volume was designed by each student separately based on what we needed to write down. Here are a few things to remember about data charts and recording data.

  • Have each student design her own based on ability- parents can step in when columns are missing.
  • Give hints or general categories students need to remember when constructing their own chart. It’s ok if the charts turn out differently from others as long as they record everything.
  • Creating their own data chart is a great way to learn the skill of organizing information. I think we underestimate the importance of our homeschooled students being able to organize information on their own- without the help of a printable!
  • Remember printables are fun, but they aren’t necessary and sometimes they slow you down- like when you are spending all your time looking for ones you’ve already printed or when you can’t find just the perfect one.
  • Scientists in the field must create their own data charts since they often design their own experiments. Step boldly!

Our Findings- How Accurate are the Volumetric Tools?

Blog, She Wrote: Comparing the Accuracy of Liquid Measurement Tools

What were the results?

  • All volumetric containers are not the same!
  • The graduated cylinder has more markings and measures more accurately – it was certainly easier to determine an accurate volume with more gradations.
  • The readings on the graduated cylinder were higher than the same volume measurement in the other tools.
  • The larger the container, the larger the discrepancy. The largest beaker was off my 20 mL or more!

What does it all mean? Well, it means if you want accurate volume without using a volumetric flask, use the graduated cylinder for the best results. Always use the container that will reasonably hold your liquids. If you use the extreme opposite, your readings will be less accurate.

Does My Homeschool Need Volumetric Measuring Tools?

Some of you might be asking whether or not it’s a good idea to invest in some volumetric containers for your homeschool. Is it a good idea? Here are a few things to think on:

  • Using containers meant for science frees up your kitchen tools- I prefer to use science tools for science and kitchen tools for the kitchen. That might be the science teacher talking, but it’s more than that!
  • Some chemicals don’t belong in vessels we eat from- Perhaps your wet labs aren’t dangerous, but some of them might be.
  • Using science tools reinforces safety measures- We don’t eat in the lab! Nor should we really eat from vessels used in the lab.
  • Ensures your students know how to measure volume accurately using appropriate tools
  • Your students will be versed in labware and how to use it
  • It helps our science to be more accurate- rather than guessing at volume when your liquid falls somewhere between 50 mL marks!

It’s easy to start out with a few beakers and graduated cylinders. We have a mixture of plastic and glass, but plastic lets me relax a little more. I would recommend a 100 mL graduated cylinder, 250 & 500 mL beakers at a minimum to start. If you work in small volumes, a 10 mL graduated cylinder is a good size.

Even the simplest of labs can introduce a great deal of concepts and provide plenty of practice at homeschool science. It’s important to use scientific volumetric tools as much as possible. Your measurements will be more accurate!

facebooktwittergoogle_pluspinterestmailby feather

Geography Quest: Shark Edition

Blog, She Wrote: Geography Quest- Shark Edition

National Shark Week begins on August 10, 2014. Are you studying the ocean or its creatures? Need a topic of focus because the summer is getting long? There are many resources available for Shark Week and I thought it would be a great opportunity to give you a new Geography Quest. Geography Quest: Shark Edition.

Species of Shark & Their Distribution

Ever wonder where various shark species are found around the world? A simple web search revealed some great sites for answering this question. Do some research and choose information to represent on a map.

  • Shark Foundation Shark Database- This site contains shark classification and distribution information. It has an interactive map to visually see the range. You can click on an area in the world and see a long list of shark species found there. Use this information to map several species of shark around the world.
  • Shark Trust- Traveling around this website will lead you to a Shark Sighting Database where you can see where people have sighted sharks. This is a great site to learn more about shark morphology and sharks in the news. Take a look!
  • Habitat & Distribution of Sharks- Learn about where sharks are found in the ocean. Are they surface dwellers? Deep swimmers? What conditions are best for sharks?
  • Shark Attack Map- From surfertoday.com shows where shark attacks have happened. Would your student like to make a shark attack map of his own?
  • Choose Some Information from Your Research to Make Your Own Map- Choose one species or several or choose an area of the world to map all the shark species found there.

Blog, She Wrote: Geography Quest- Shark Edition

Map Shark Migration

Do sharks remain in the same areas of the ocean at all times? Do they travel based on the weather? Time of year? Food needs? Read about shark migration and make a map. A lot of shark tracking is going on, but it is by species. I will list a few sites here for you.

Blog, She Wrote: Geography Quest: Shark Edition

Shark Week Resources

There is no shortage of hype around shark week! Here are some of my favorite picks from my searches.

Shark Art with Chalk Pastels

Tricia at Hodgepodge is releasing a new chalk pastels eBook for National Shark Week. Check the links below for a shark art video tutorial along with the new book.

Blog, She Wrote: Geography Quest- Shark EditionHow to Draw a Shark with Chalk Pastels- Nana does a nice little Great White Shark video tutorial with her chalks. We enjoyed this!

You’ll find 10 shark tutorials with instructions for how to draw them in chalks along with information about the shark species. There’s a paragraph or two with general facts at the start of each lesson and embedded in the art directions are more tidbits about the shark! I loved this!

Shark Art Tutorials

Through August 10, 2014, the new shark eBook is available for $5.99. Once shark week begins, the price will increase to it’s regular price of $7.99.

 

Gear up for National Shark Week by gathering your art supplies and making sure you check out the Discovery Channel’s programming. Trim up some mapping skills by having your kids do some shark research and map out the distribution and migration of sharks. Have fun!

Big Book of Homeschooling

Shark Art Tutorials

facebooktwittergoogle_pluspinterestmailby feather

Tips for an Excellent Insect Display

Blog, She Wrote: Tips for an Excellent Insect Display

Labeling Your Insect Collection

As you might have predicted, there are rules on how to label an insect collection for display. Here are a few key points:

  • Number Labels- Each insect in the collection gets a number. If it is a 4-H collection, a numbered insect must have been collected in the current fair year (not before the previous year’s fair). You can have those insects in a collection, but they cannot be numbered in that year’s collection. These labels are the last ones on the pin with the insect.
  • Collection Labels- The first label on the insect pin (underneath the insect) is the collection information. Where the insect was collected and when along with the name of the collector.
  • Identification Label- For 2nd year collections and up, you must include another label which goes between the number and collection information. It will have the family name of the insect as well as the genus and species. Correctly identifying the insect to the species is important for point value.
  • Order Labels- These are larger labels and they are pinned inside the box. When you organize your collection do so by order.
  • Common Name Labels- Required after the first year, these labels tell the common name of the insect and usually include a family name (so not just “fly” but “crane fly”)

Keeping a Collection Record

Along with all the labeling in the box, you must turn in a collection record. Since the collections are additive over the years, these records can be many pages long. Below are listed the information you need to keep:

  • Insect Number- comes after you’ve labeled your insects
  • Common Name- 2nd year and beyond
  • Order
  • Family
  • Genus Species
  • Locality- location of collection
  • Date Collected
  • Place Collected- what habitat

A first year collection only needs to be identified to the order. After that, more work is required!

Blog, She Wrote: Tips for an Excellent Insect Display

Other Tips for Insect Displays

In addition to the labeling, here are a few more helpful hints:

  • Group orders of insects together in the collection and place the order label nearby
  • Numbers within an order should be chronological
  • Place the vials toward the bottom of your collection- So if they come loose, they don’t wreck other insects in the box!
  • Keep a collection record as you go- This is a time saver when you are preparing your collection for evaluation!

For more information on making displays, check out How to Make an Awesome Insect Collection from Purdue which follows 4-H guidelines for entomology projects.

This has been an exciting project area for us this year. We’ve already started next year’s collection. As of publishing time for this post, the collection pictured here has won a blue ribbon and a project excellence for first year collections and is headed for the NY State Fair next month.

Enjoy the collecting!

Other bloggers in the iHN are sharing their series this week for 2014’s summer Hopscotch. Don’t forget to hop over!

iHN July 2014 Hopscotch

facebooktwittergoogle_pluspinterestmailby feather