![Browning apple](/sites/default/files/styles/resource_card_image_360x300_/public/2020-03/Browning_apple.jpg?itok=0ChBaFX8)
Why Do Apples Turn Brown After You Cut Them?
STEM Explained
Has your fresh juicy apple turned an unsightly brown? Learn about the redox reaction behind the transformation.
![Water droplets on succulent leaves](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/Succulent_leaf.jpg?itok=55kCziIw)
How Do Plants Survive in the Desert?
STEM Explained
Plants need to exchange gases and water with their environment as part of photosynthesis. Some plant cells have evolved specifically for this purpose.
![Cartoon leaf holding an umbrella over baby plant](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/cartoon_acid_rain.jpg?itok=J4BMIwgR)
What is Acid Rain?
STEM Explained
Acid rain is any precipitation that has an unusually low pH. It can be rain, snow, fog, etc. But what is a low pH and why is this a problem?
![Hamilton Street Railway bus in downtown Hamilton, Ontario © Adam E. Moreira [CC BY-SA 3.0], Wikimedia Commons](/sites/default/files/styles/resource_card_image_360x300_/public/2019-08/Hamilton%20Street%20Railway%20bus%20in%20downtown%20Hamilton%2C%20Ontario%20%C2%A9%20Adam%20E.%20Moreira.jpg?itok=1ZSDJMZQ)
Fueling Internal Combustion Engines
Backgrounders
Learn about the wide variety of fuels used in vehicles.
![Cartoon of people cleaning teeth](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/Cartoon_dentists_cleaning_a_tooth.jpg?itok=vK4Ow00y)
How can chemistry help you take care of your teeth?
STEM Explained
What are your teeth made up of? What chemistry is at work in your mouth? Why do some people get cavities even if they brush regularly?
![Why do leaves change colour in the fall?](/sites/default/files/2019-08/wiki-autumnleaf.jpg)
Why do leaves change colour in the fall?
Hands-on Activities
How do the green leaves of summer change to vibrant colours in fall? Explore plant pigments in this chromatography activity.
![A melting world-shaped glacier](/sites/default/files/styles/resource_card_image_360x300_/public/2019-11/melting_world-shaped_glacier.jpg?itok=-lrMUAJG)
What is Ocean Warming and Why Does It Matter?
STEM Explained
Oceans absorb the greatest amount of solar radiation on Earth. Ocean warming can lead to glaciers melting and ocean acidification.
![What are curds and whey?](/sites/default/files/2019-08/what-are-curds-and-whey.jpg)
What are curds and whey?
Hands-on Activities
It starts with curds and whey! Explore the basic chemistry behind making cheese in this hands on activity.
![Hamilton, Ontario industrial area with Toronto skyline in the background](/sites/default/files/styles/resource_card_image_360x300_/public/2019-09/the-hamilton-industrial-area-with-toronto-skyline.jpg?itok=shKtb5Tb)
What are Greenhouse Gases?
Backgrounders
This backgrounder explains what greenhouse gases are and how they contribute to climate change.
![What are the effects of acid rain on rocks?](/sites/default/files/2019-08/what-are-the-effects-of-acid-rain-on-rocks.jpg)
What are the effects of acid rain on rocks?
Hands-on Activities
Learn about the chemical reaction that happens between acid rain and limestone.
![What happens when acids and bases mix?](/sites/default/files/2019-08/what-happens-when-acids-and-bases-mix.jpg)
What happens when acids and bases mix?
Hands-on Activities
Learn about acid-base reactions. Make you own pH indicator and test it with different solutions.
![A set of lipstick in various colours](/sites/default/files/styles/resource_card_image_360x300_/public/2020-02/Assortment_of_lipsticks.png?itok=z_U-KbdM)
The Chemistry of Lipstick
STEM Explained
Learn about the organic compounds that make up lipstick as well as about some of the chemistry that goes into this popular cosmetic.
![Is there a difference between baking powder and baking soda?](/sites/default/files/2019-08/is-there-a-difference-between-baking-powder-and-baking-soda.jpg)
Is there a difference between baking powder and baking soda?
Hands-on Activities
Explore acid-base chemical reactions that really get things bubbling in the kitchen!
![illustration of a hydrogen car](/sites/default/files/styles/resource_card_image_360x300_/public/2019-10/Hydrogen_car.png?itok=-Ul7H9-e)
The History and Uses of Hydrogen
STEM Explained
Hydrogen’s tendency towards combustion is what makes it both a dangerous chemical element and a useful energy source.
![How can I stop bananas from turning brown?](/sites/default/files/2019-08/how-can-i-stop-bananas-from-turning-brown.jpg)
How can I stop bananas from turning brown?
Hands-on Activities
Explore the chemistry behind why bananas turn brown. Can chemistry also help prevent this?