Chemical vs. Physical Changes: Let’s Get it Straight!

Breathing, cooking, exercising, and more: we are surrounded by changes every day! But how do we keep straight which are physical and which are chemical?


Physical Changes

Physical changes involve chemicals getting rearranged in a new way, but without getting destroyed or irreversibly combined. The molecular structure of the original substance(s) is the the same after the change, which means it is still the same substance. A common example is of water freezing; the liquid water becomes a solid, but it is still water. Ripping paper is another example because while it may be in pieces, it’s still paper. Signs of a physical change include:

  • Expected color change
  • Change in size or shape
  • Change in state of matter
  • Reversible
  • No new substance formed!

Chemical Changes

Chemical changes, or reactions, involve chemicals getting rearranged in irreversible ways. We bring in the term “reaction” when dealing with chemical changes because the chemicals involved actually react with one another to form a new substance (that’s why we call the parts in a chemical reaction the reactants). The ways chemicals can react are many: two substances can combine to create a totally new one (Direct Combination), a substance can permanently break apart, separating into different substances (Decomposition), or maybe a substance combusts as it reacts to oxygen (Combustion) (see more types of reactions here). Whatever the reaction, it’s important to recognize that one or more new substances are formed! Burning wood is a common example of a chemical reaction because as the wood reacts with oxygen after it has been ignited, it creates smoke and ashes. Signs of a chemical reaction include:

  • Unexpected color change
  • Change in temperature as energy is released or absorbed
  • Gas created
  • Irreversible
  • New substance formed!

Confusing Cases

In many cases, it may seem a simple task to distinguish between the two, but it gets more complex when we’re dealing with changes that seem irreversible when they’re not. For example, we may look at a glass of Kool-Aid and think to ourselves, “I made Kool-Aid. It was water and a packet, but now it’s dissolved together to make new drink, so it’s a new substance.” However, if you think back to the list of signs of a physical change, you’ll realize that not only was there an expected color change (the water didn’t turn purple when you added red Kool-Aid!), but that it is reversible–the water could evaporate in the form of gas, leaving red Kool-Aid residue behind! The water is still water, and the Kool-Aid is still Kool-Aid, and since no new substances were formed, it is a physical change!

Another example of confusion is in cooking eggs–after all, isn’t it still an egg before and after tossing it in pan? However, on a molecular level, the egg has changed completely as the proteins have bonded in new ways, making it a new substance. Additionally, because of the change, it is not possible for the egg to ever become raw again, and since a new substance was formed, it is a chemical change!

For some practice using the different lists of signs for each type of change, and to view several other examples in action, check out this Prezi below!

Photo credit: Faris Algosaibi

Other Sources:

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Practical Student Blogging

If you’re like most teachers, you have 47 other tabs open besides this one: your grade-book, email, lesson plan resources, and a couple articles on stress management.  So how can you implement student blogging without tipping the scale?


Blogging Benefits

The countless benefits of student blogging are likely what led you to this article today!  Some that we at the Honors Grad U family have witnessed through experience include:

  • Authentic audience: Parents, teachers, peers, and even fellow students across the globe can view, comment, and contribute to the learning!

  • Developing practical tech skills: Besides the obvious benefit of typing practice, blogging is a perfect tool for introducing and practicing skills from copying and pasting to simple HTML editing to maintaining various digital accounts.

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  • Multimedia Literacy:  Growing up, we all made dioramas from shoe boxes, wrote 5-paragraph essays, and crafted posters.  However, 21st century students can and need to also become fluent in an ever-expanding pool of digital resources.  Blogging gives them practice in creating and sharing pictures, Youtube videos, Educreations, Thinglinks, Infographics, Prezi’s, and much more!

  • Engaging Assignments/Projects Through Student Choice & Variety: It can be difficult to keep the passion burning when you introduce a persuasive writing unit.  However, when you also introduce the idea of also including persuasive imagery, as well as actually sharing their work with their intended audience, suddenly things get much more intriguing and personal for each student!

  • Simpler Teacher/Student Collaboration: You’ve experienced the dredge of writing comments on dozens to hundreds of assignments–and that’s only after deciphering questionable handwriting!  Once students have posted various artifacts to their blogs, you can easily type feedback–and depending on your platform, that can even be made private!

  • Easily Accessible Digital Learning Portfolio: Say goodbye to clunky binders with half-ripped-out pages from September by the time you get to March!  If you just consider the use of a few tags, you can already imagine how much easier it would be to navigate the archives of a digital portfolio.

Simple Steps for Success

  1. Pick a Platform:  Spend time exploring your options, privacy needs, and budget.  Most platforms are free on a basic level, but if you want more storage, you’ll want to consider budgeting for your account.  You can even try talking to your administration for some budgetary help, especially if they want to purchase a group package for your school!  Kidblog, WordPress, and Edublogs are all common options that allow you to add users with you as the administrator and moderator!

  2. Permission: Make sure you discuss your school’s privacy policies with your administration before you get started, especially if you’re the first teacher at your school to start student blogging!  You may just need to make a permission slip from parents for each student, or you may find that media permission slips have already been submitted to the school!

  3. Carve out class blogging time: This is probably the hardest step of all!  However, if you are an elementary school teacher, just a weekly 30-45 minute time slot should be enough to get them started!  For secondary levels, you may be able to do more at-home blogging assignments, but you’ll still want to establish at least a little class time for modeling how to use the resources (see below).

  4. Internet Safety & Respect:  Before students enter their blogs for the first time, make sure they are all familiar with basic safety rules, including sharing their personal information (this website is full of teaching ideas).  Also, practice proper etiquette in commenting on paper (see lesson ideas here), before launching into the real deal!  Creating and signing a class blogging contract for future reference is always a plus, too!

  5. Establish clear expectations:  Decide what’s most important to you for their blogs.  If you expect capitalized titles, tags for every post, and a reflection, make sure it’s clear from the beginning.  Let students know you won’t publish any posts missing basic expectations (but make sure they are reasonable for your students’ level as well)!

  6. Choose a few resources: While you’ll definitely want to introduce them one at a time (see below), spend some time beforehand identifying and familiarizing yourself with the main resources you want to teach your students to use.  We recommend choosing one resource for each subject you want your students to be able to exhibit.

    1. Math: Educreations is fantastic resource that allows students to explain their thinking as they draw while also recording their voice!

    2. Reading: You can use Audioboo to have students record their reading skills throughout the year!  Particularly for younger students, it would be powerful for them to literally listen to their progress from September to May.  For a free option (Audioboo maxes out after 3 minutes), you could also use Youtube, even covering up the camera so it just records their voices.

    3. Writing: Obviously, the simple text of a blog post is a great way to share student writing throughout the year. However, you can easily liven things up by introducing a word cloud maker like Wordle.  Not only would it add some beauty to their published piece, but it can also help students visualize their most common word usage in essays!

    4. Art: Older students will likely already be familiar with Photobooth to simply take pictures of their art pieces, but you may need to spend time teaching younger students how to take and upload photos to their blogs.

    5. Science/Social Studies: Thinglink allows students to collect several online articles, videos, and photos into one beautiful interactive presentation!

  7. Introduce one at a time:  Even if it takes several months, it is worth teaching and  practicing just one resource at a time!  Before moving to the next resource, thoroughly familiarize them by allowing them to explore several examples, create a few of their own on their blogs, and collaborate with one another’s work through commenting.  We’ve also found it effective to print and display a board of step-by-step guides for each resource for students to reference in the future.

  8. MODEL, MODEL, MODEL!!  Every chance you get, model how you would like them to use each resource.  Using your own blog account, create multiple examples of each resource for them to reference.  Remember to also model quality comments on their own blogs throughout the year!

  9. Make sure it’s accessible to parents: One of the most rewarding aspects of student blogging is to watch parents connect authentically with their child’s work!  Make sure links to student blogs are available on your classroom blog, and/or email reminders to parents after students have finished blogging projects!

Additional Ideas

Once you get into a groove with blogging, here are a few other ideas to consider to keep things exciting for your class:

  • Student Blogging Challenges: Websites like this one offer wonderful challenges for students to tackle in their blogs!  You can always get creative and craft a few of your own!  For high schoolers, this can even be in the form of working on scholarships, such as our very own Honors Grad U Scholarship, as students share their progress on their blogs!

  • Quadblogging:  This is one of the best ways to connect globally with classrooms just like yours!  Four classrooms form a quad, with each class taking turns being the  highlight classroom, while the other three visit their blogs and leave comments!  One member of our Honors Grad U family has experienced connecting with classes from the U.K. & China!

  • Consider social media: Another way to break down your four classroom walls is social media, including Twitter (Click here for our post on Twitter for teachers)!  Educational hashtags can allow your students to quickly find feedback from around the world.  For example, #comments4kids is specifically intended to post links to student work for others to leave comments!

  • Badges: www.classbadges.com is a fun way to motivate students to work to visually earn various achievements!  You could also use them in conjunction with your student blogging challenges!

Hopefully, these steps allow you to tackle student blogging in a manageable, practical way!  Leave a comment if you have any questions or additional ideas as you get started!


photo credits: DeathToTheStockPhoto (featured image)

Practicing Self-Development

Personal development activities improve awareness, identity, develop talents, enhance the quality of life, and bring you closer to your dreams. Honors Grad U is a big promoter of self-education and has provided tips below on how to be the best you:

Continue reading Practicing Self-Development