Lab Activities
ECS 350 Resource Package
Cole Hintz
Physical and Chemical Changes
Important: When doing classroom labs wear safety glasses at all times please.
Be careful when using fire too please…it burns…YEOUCH!!
These activities are meant to help you look further into the differences between
physical and chemical changes as well as why these changes could be important.
As a quick refresher…
Physical changes – a change that may alter the form of something but does
not create a new substance. These types of changes can be reversed fairly easily
because there are no new bonds that are formed. A change of state (solid ->
liquid -> gas or vice versa) is a physical change.
Chemical changes – a change where the end product (what the substance
changes into) is different than what you started with. These are chemical
differences because new bonds have been formed to create something new. The
new substance has different properties (melting point, boiling point, colour, etc.)
than what it did before. Indicators that a chemical change has occurred are that
a precipitate is formed, there is a colour change, a gas is released, there is a
temperature change, and light or heat is given off.
Throughout these activities you will be asked to make predictions followed by an
observation. When making your observation it is important to:
1.) Describe what you started with.
2.) Describe what happens during the activity.
3.) Describe what you ended with.
*Detail is important and you can even use pictures where it could better help to
show what you saw.
Lab Activities
ECS 350 Resource Package
Cole Hintz
What I’m looking for.
Observations:
Yes Not
Yet
I can make observations that include what I started with (words or a
drawing works).
I can make observations that include a description of what was
happening during the activity.
I can make an observation that describes what we ended up with
(words or a drawing works).
I can make descriptions that provide enough detail.
I can make observations that make sense and are easy to understand.
/10
Predictions and Explanations
I can use the questions to make connections between the activities and
their importance.
I can show that I understand what a physical and chemical change is.
/4
I can work safely in a lab environment.
/15
/1
Lab Activities
HEADS UP! You’re
ECS 350 Resource Package
using fire here. Make
sure you don’t get
burned.
Cole Hintz
Fire!!
Predict:
How do you light a fire? What do you need?
What does a fire need to burn?
Does fire result in something new being produced?
Is fire an example of a physical or a chemical change?
Observation:
Observe: Light the candle and make
sure it is burning. Watch the candle
and make a note of what is
happening. Next place the beaker
upside down over the candle.
Explain:
What happened when you placed the beaker over the candle? Why?
What did the candle have before that it didn’t have afterwards?
Why is it probably not a good idea to inhale all the smoke you can if your house is on fire? Does
fire produce anything new?
Why do Class A fire extinguishers (used for wood, paper, and other combustibles) eject carbon
dioxide?
Lab Activities
ECS 350 Resource Package
Cole Hintz
Fire!! (Part 2)
Predict:
Candles melt and take on weird shapes when this happens.
Is this a chemical or physical change?
What kind of things burn really well?
Are oranges flammable?
Observation:
Observe: Take a piece of orange peel
and briefly heat it over the flame.
Now pinch the peel, close to the
flame, so that the juice in the peel is
sprayed at the flame.
Wear safety glasses and be cautious
of the flame.
Explain:
Was there a chemical change as you sprayed the orange peel at the flame? How do you know?
If there was a new substance formed where did it go? Was only the orange peel and fire involved?
What could oranges have in their peels that would cause them to be flammable? [Hint. Think about
why we like to use fruits for nice smelling perfumes]
Why is it useful for us to have substances that burn very quickly?
What kind of problems does having these kinds of substances present? What do they usually produce
(Think about global warming)?
Lab Activities
ECS 350 Resource Package
Cole Hintz
Rust
Predict:
Do some chemical changes just happen? Why?
Is rusting a physical or chemical change? How do you know?
Observe:
Using the dissecting microscope look
at the surface of the clean metal.
Now look at the surface of the rusted
metal. Note any differences or
similarities you may see.
Observe (label what you are looking at and draw what you see):
Explain:
Where does rust come from? Is this a physical or chemical change?
Is rust hard to remove? Why?
What are some common things associated with rust (What are the ingredients needed for rust?)?
Why would I want to park my car in the garage if I didn’t want it to rust? How does painting help
prevent rust?
Why are older cars usually more rusted? What does this tell you about how quickly or how slowly the
‘rusting’ process takes?
Lab Activities
ECS 350 Resource Package
Brrrrrr!
Cole Hintz
Safety
glasses
please!!
Predict:
What are some ways to identify that a chemical change has
occurred?
How does heat relate to chemical changes? Physical changes?
If something gets colder is it a physical change or chemical
change?
Observe:
Safety Glasses Please!
Keep the contents in the Ziploc bag. Without
opening the outside bag empty the inside bag
into the outside one. Touch the bag and observe
what happens.
Explain:
What happened?
Was this a physical or chemical change? How do you know?
How would you have expected heat to react? Why would it be different?
Marcello is playing soccer and sprains his ankle luckily you’ve learned a thing or two and can
help out. Do you use your idea directly on his ankle? Or do you use a towel to wrap up your slick
idea? Why?
Lab Activities
ECS 350 Resource Package
Cole Hintz
Iced Tea Time
Predict: Take a drink of water and pause for a discussion
break.
What are some things that identify a chemical change has
occurred?
Does a colour change always mean a chemical change has
occurred? Why?
Observe: Make yourself a glass of iced tea. Make sure you pay attention to
what happens. While you contemplate iced tea and chemistry here are
some jokes for you:
Two atoms are walking down the street.
Says one atom to the other, "Hey! I think I lost an electron!"
The other says, "Are you sure??"
"Yes, I'm positive!"
If you're not part of the solution, you're part of the precipitate!
Explain:
What did you end up with?
What happens on the molecular level when you make iced tea?
Is it easy enough to reverse what has happened? How would you do that?
Why is colour change not always a good indicator of chemical change?
Lab Activities
ECS 350 Resource Package
Cole Hintz
Indigestion?
Predict:
What is going to happen when you put an Alka-Seltzer tablet in water?
Is there going to be a change?
If there is a change will it be physical or chemical? Why?
Observe:
Drop the Alka-Seltzer tablet in a
beaker of water. Pay attention to
what is going on.
Explain:
What happened?
Was there a chemical or physical change? How do you know?
Was anything new formed? If so where do you think it went?
How could the products of this change be useful? What do we use antacids for?
Why might it be important to have medications such as this that changes quickly?