Big Idea 9 - Changes in Matter

Which change to an object best indicates a chemical change?

• Changes in odor

• Changes in size

• Changes in shape

• Changes in volume

Answer explanation

Some chemical changes produce new smells. The chemical change that occurs when an egg is rotting produces the smell of sulfur. If you go outdoors after a thunderstorm, you may detect an unusual odor in the air.

Tags

NGSS.MS-PS1-2

Parker burned a pieces of wood while camping. Which explains what happened to the wood once the fire burned out?

• a physical change occurred

• a chemical change did not occur

• a new substance was formed

• all of the wood became gas and blew away

Answer explanation

When you burn wood, the carbon in the wood reacts with oxygen in the air to create ash and smoke, and energy in the form of light and heat. This is a permanent change that cannot be undone – you cannot turn ashes back into wood.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

Bill Nye the Science Guy is using his cool Interactive Science Journal to document an investigation which he is completing on air temperature. He goes outside and observes the thermometer and reads the temperature as 90 degrees Fahrenheit. As a scientist, what should he do next?

• He should let all his friends know the temperature

• He should record the temperature in his Cool Science Journal

• He should talk to a professor about the temperature.

• He should take the temperature somewhere else

Answer explanation

A Scientist should always record their data!

Josh was home when the power went out. He walked to the kitchen to get a candle and knocked over a lamp. He lit a candle with a match to get the candle to burn. He used the light to help find his way to his bedroom, where he laid on his bed and went to sleep. Which of these events was a chemical change?

• 
• 
• 
• 

Answer explanation

Fuel + heat + oxygen = fire The fuel comes from the sulfur (that's another chemical) and wax in the head of the match. ... When it gets hot, it releases a lot of extra oxygen and heat. This makes the match head burn quickly and strongly. When you put it all together – the heat, the fuel, and the oxygen – you get a flame!

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Lauren left her metal scooter out in the rain. After some time the scooter developed rust. Lauren believes her scooter went through a chemical change. Is she correct?

• Yes, she is correct rust is a form of a chemical change.

• No, she is not correct rust is a form of a physical change.

Answer explanation

Rust is a type of corrosion. It happens to iron and its alloys when it is exposed to air or water for a long time. Rust slowly decomposes iron into other chemicals, because of a reaction with the oxygen molecules. Both air and water are needed for rust

Tags

NGSS.MS-PS1-2

Which of the following is an example of a physical change?

• 
• 
• 
• 

Answer explanation

A physical change affects the physical properties. Think about a pencil that is broken in half. The broken pencil is still a pencil, but its physical properties, like size and shape, have changed.

Your teacher asked you to write a brief summary on physical changes. Which gives the best definition of a physical change?

• a change that gives off heat

• a change in size, shape, or state

• a change that makes a new substance

• a change that causes a new odor to be given off

Answer explanation

A physical change is a change to the physical properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape (volume and size), color, texture, flexibility, density, and mass.

Which observation best supports the prediction that a physical change occurred.

• The materials bubbled and fizzed when mixed.

• The liquid evaporating into gas

• The odor changed when the materials were mixed.

• The materials created a new substance when mixed.

Answer explanation

The evaporation of water is a physical change. When water evaporates, it changes from the liquid state to the gas state, but it is still water; it has not changed into any other substance.

Fred is preparing for his birthday party. His mom placed balloons around the house. By the end of his party, the balloons had lost air. Which best describes the physical change in the balloons?

• Change in size

• Change in shape

• Change in color

• Change in substance

Answer explanation

A deflated balloon is a physical change because only the size of the balloon changes , no change in chemical properties of the balloon occurs

While waiting for breakfast, Jordan noticed several different changes of matter taking place. Which of the following is an example of a chemical change?

• fruit mixing

• water boiling

• butter melting

• pancake frying

Answer explanation

When you cook your pancake in a frying pan, the cooking temperature causes a chemical reaction between the sugars in the starch and the amino acids in the proteins.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5