BCScience great 2 (June 2016)2Big Idea: Materials have the right to be changed through physical and also chemical processes.

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NTK-6 scientific research and technology Curriculum (NWT, 2004)5Matter and Materials: properties of and Changes in Matter
NUK-6 science and technology Curriculum (NWT, 2004)5Matter and also Materials: nature of and also Changes in Matter
YTScience grade 2 (British Columbia, June 2016)2Big Idea: Materials deserve to be readjusted through physical and chemical processes.
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How perform you walk from flour, sugar, and also eggs to cookies? Or indigenous fruit juice to popsicles? make food is all about changes! These have the right to be physical changes or chemical changes.

Physical Changes

A physical adjust is a readjust in the state that matter. There are three key states of issue - solid, liquid and also gas.

If you freeze fruit juice to do a popsicle, this is a change in state. The juice transforms from a liquid to a solid. Ice cream melt on a warm day is additionally a readjust in state. The ice cream cream transforms from a solid to a liquid. The juice and ice cream room still juice and ice cream, also when they adjust from one state of matter to another.

Misconception Alert

Sometimes when you cook a fluid it becomes a solid, like when a raw egg becomes a scrambled egg. This is not a change in state. Changes in state can usually be reversed. Girlfriend can’t adjust scrambled eggs ago into life eggs!

If you break something big into smaller pieces, this is additionally a physics change. Once you grate a item of cheese for her pizza, friend are transforming the block that cheese. The cheese is quiet cheese, also though the little shreds don’t look prefer the block the cheese you began with.


Left come right: Frozen fruit treats, melting ice cream cream and also grated cheese (Sources: LauriPatterson via iStockphoto, Collin BH via iStockphoto and (sergio_kumer via iStockphoto).


Sometimes physical alters are hard to see. If you placed some sugar right into water and also stir, soon you wouldn’t be able to see the sugar. It hasn’t disappeared! The sugar has actually just been broken down right into pieces that space too small to see. 

It’s choose if you combined a couple of red candies right into a big bag of blue candies. The red candies might be hard to see, yet they’re still there. 

Chemical Changes

chemical change is a adjust in what something is make of. We can tell the a chemical change has occurred by spring for certain clues. 

One reservation is gas. Gas is produced during a chemical change. The following time you bake a cake or flip a pancake, look for the bubbles. Inside each balloon is a small bit of a gas. This gas is made once the ingredients adjust each other. 

Bubbles help make the food you bake fluffy. If you cut into a cake, you can see the spaces whereby there were bubbles of gas in the wet batter.

Misconception Alert

Not all bubbles come from chemistry changes. When you mix batter through a whisk, you might see bubbles. This are just air that gets trapped in the batter throughout whisking.

Speaking that gas… smell is the second clue that a chemical readjust is happening. Sour milk, rotten bananas and mouldy cheese all do smells. These smells warn united state not come eat this food. Food that’s rotten or mouldy can make united state sick. 

But over there are many smelly foodstuffs that room perfectly for sure to eat! Blue cheese and Durian fruit have very strong smells. They will not harm you unless you room allergic to them. Everyone has various tastes. Lots of people love foods with distinct odours. 

Did girlfriend know?

Some civilization say Durian fruit smells like paint thinner and also onions, with a note of stinky gym socks!

Can girlfriend think of nice smells that might come from the kitchen? The smell of baking bread or roasting turkey are signs that chemical alters are happening!


From left come right: world smelling new bread, roast turkey and also simmering soup (Sources: gpointstudio via iStockphoto, FG trade via iStockphoto and also eclipse_images via iStockphoto).


The 3rd clue is a adjust in colour. Think the the perfect golden brown girlfriend can get when friend toast marshmallows end a fire. Or the dark brown colour as soon as you coincidentally burn it. Whoops! 

When tomatoes readjust colour from eco-friendly to red, that way they are ready to eat. As soon as bananas change from yellow to black, that way they are not an excellent to eat anymore.


Toasted marshmallows, scorched toast and also overripe, ripe and also under ripe bananas (Elenathewise via iStockphoto, ImageDB via iStockphoto and also kolesnikovserg via iStockphoto).


Colour adjust can be a tricky clue. Periodically it’s hard to tell if a adjust in color is since of a physical adjust or a chemistry change. 

Imagine that you add red food colouring come white icing. Now you have pink icing. Perform you think this is a physical adjust or a chemistry change? mental stirring street in water? Food colouring works the exact same way. The colour simply spreads v the icing. The doesn’t adjust the icing itself. This is a physics change.

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So how can you phone call if a readjust is physics or chemical? questioning yourself:

Is the substance the very same thing now as it was before the change? If that the same, that is a physics change. If that isn’t, the is a chemical change.Was over there a adjust in colour or smell? to be a gas formed? If any of these points happened, it to be a chemistry change.Can the change be reversed easily? If so, it to be a physics change.

Your kitchen deserve to be an amazing laboratory to explore the human being of chemistry!