Changes that materials undergo

Bread placed in a toaster turns brown then black if too long. What is needed for this chemical change to take place?

• Heat energy had to be added.

• Heat energy had to be taken away.

• A certain amount of time had to pass.

• The bread had to be taken out of the wrapper.

Sheena decided to eat an apple and cut it into two. After a few seconds, her mother asked her to buy at the sari-sari store and left the apple in an open area. When she come back, she noticed that the apple turns brown. What could be the possible reason for this?

• Her younger sibling paint it.

• Her mother put a brown sugar on the top of the apple.

• The apple turns brown because it is exposed to air.

• The apple turns brown because it is sliced.

Manang Lina often buys vegetables in the market and put it in her dining table when she got home. A week after, she noticed that her vegetables rot fast and feel worried about it. What advice can you give to Manang Lina?

• Manang Lina should put it in a refrigerator.

• Manang Lina should give it to her neighbors.

• Manang Lina should throw it away.

• Manang Lina should cook it anyway.

Mrs. Bayron's science class is learning that changes happen in materials under the following conditions:

1. Presence and lack of oxygen; 2. Application of heat.

Which of the following shows a change due to the application of heat?

• Paper being ripped.

• Water freezing into ice.

• A chocolate melting inside the oven

• An apple that rots.

Natalia baked cookies for the family. When the cookies came out of the oven, the color has changed and it smelled different than the raw cookie dough. What kind of change has taken place in the cookies?

• Chemical change- decaying

• Chemical change- cooking

• Physical change- cooking

• Physical change- breaking

Megan is observing a kiwi for 10 days. She noticed that the kiwi becomes soft and brown spots appear on the skin. The kiwi is starting to give off a strong odor. Megan hypothesizes that the kiwi changed because of the heat in the room. What observation and inference that Megan made?

• Megan noticed that the color has changed.

• Megan infers that the heat is responsible for it.

• Megan notices that the color has changed and infers that the heat is responsible for the changes.

• Megan does not observe any changes.

Louiela is making smores over the campfire. Her marshmallow falls into the fire and burn. Which is true about her marshmallow?

• The fire produces no change to the marshmallow.

• The fire produces a physical change to the marshmallow.

• The marshmallow turn into ashes.

• The ashes left behind will turn back into a marshmallow.

You forgot to dry the bread knife when you washed it. Days later, reddish brown spots appeared on it. What kind of change has taken place?

• Environmental change

• Physical change

• Personal change

• Chemical change

Chewing food to break it down into smaller particles represents a _______ change, but the changing of starch into sugars by enzymes in the digestive system represents a ________ change.

• Chemical, physical

• Chemical, chemical

• Physical, chemical

• Physical, physical

The statements below are the ways to avoid causing fire incidents at home, except one.

• Keep all fires and heaters well guarded.

• Keep portable heaters and candles away from furniture and curtains.

• Do not smoke in bed.

• Leave a pan unattended when deep frying.