This learning activity is to help you think critically and find evidence that supports your claims about whether a chemical reaction or physical changed has happened. Remember that we took focus notes about how we identify a Chemical vs. a Physical Change. If you missed that day and have not taken the notes yet you can review the Powerpoint here:
In review, when trying to determine if a chemical reaction or physical change has occurred, go through the following steps:
1. Ask yourself, “Did it create a new substance?”
2. Did any bonds between atoms break or form?
3. If you are looking at the chemical equation does it look different on the left side than on the right side of the arrow?
If you answered YES to any of the questions above, then it is a CHEMICAL CHANGE! If you answered NO, then it is a PHYSICAL CHANGE!
Sometimes it isn’t easy to see that a new substance has been formed, or we can’t look at the atoms, or don’t have the chemical formula. When we can’t use these methods we look for possible signs (hints) that it may be a chemical change. You will still need to use your critical thinking skills to decide if there are enough signs, or the right kind of signs to tell if a chemical change has occured.
SIGNS OF A CHEMICAL CHANGE
1. Change in color.
2. Change in temperature (that you did not cause).
3. Change in odor.
4. Production of a gas (bubbling or fizzing).
5. Production of sound.
6. Production of light.
7. Forms a precipitate (remember this is two liquids forming a solid).
INSTRUCTIONS:
Now that you have reviewed all the things that help you decide if a chemical change has occured, use the document below to practice.
1. Read the text in each section to find evidence for a chemical or physical change. Highlight evidence as you read.
2. Fill out the table under the text. Under CLAIM you should write either chemical or physical. Then fill out your evidence that you highlited in the paragraphs, and finally the reasoning. This should be things like (this is a sign of a chemical change, or phase changes are always physical changes.)
3. When you are done with the table answer any questions below the table.
Additional Info:
For Passage One: Glowstick Click – Click here for a video of someone activating a glow stick.
For Passage Two: What’s Poppin? – Click here for a video of a popcorn kernel popping in slow motion.
For Passage Three: Shining Seas – Click here for a video of what the paragraph is talking about. We call it bioluminescence.
For Passage Four: Cold Pack Whack: Click here for a video showing someone activating a cold pack.