Question

chemical and physical weathering
weathering is the process by which rocks are broken down into sediments. rocks can be physically or chemically weathered. physical weathering is when rocks are broken down by physical means (no chemical reaction takes place). physical weathering is also known as mechanical weathering. an example of physical weathering is ice wedging. in cool climates water seeps into the cracks in rocks during the day. at night the water in the rock freezes. when water freezes it expands - takes up more space. this is why you should never put a glass bottle full of liquid in the freezer - it can expand a break the glass. in some regions, the water freezes each night and melts during the day. this freezing and thawing cycle creates a wedge that can break even large rocks apart. in cold wet climates a lot of ice wedging occurs so lots of physical weathering takes place. other examples of physical weathering are a glacier (frozen river) scratching a mountain or an animal scratching soft rocks as it digs a hole.
chemical weathering is when a rock is broken down by a chemical reaction. oxidation - the chemical reaction that creates rust - is an example of chemical weathering. another example is when basic rocks are chemically broken down by acidic rain. acids and bases will react with each other. seashells are basic and so rocks that are made from sea shells or marine skeletons are also bases - like limestone, marble, and chalk. these rocks will react with rainwater (which is naturally slightly acidic) and will be chemically weathered (broken down) over time. sedimentary rocks are softer than igneous or metamorphic rocks so sedimentary rocks weather more easily. in warm wet climates there is a lot of acidic rain so more chemical weathering takes place. temperature and precipitation are the biggest climatic factors that influence weathering.

1. what are the two types of weathering?
2. what is another name for mechanical weathering?
3. what is mechanical weathering in your own words? give an example

Explanation:

Question 1

The text states that rocks can be weathered physically or chemically. It defines physical weathering (with no chemical reaction) and chemical weathering (with a chemical reaction). So we extract these two types from the passage.

The passage says "Physical weathering is also known as mechanical weathering", so we can directly get the answer from this sentence.

First, rephrase the definition of mechanical (physical) weathering from the passage: it's breaking rocks by physical means (no chemical reaction). Then, use an example from the passage like ice wedging (water in rock cracks freezes, expands, and breaks rocks) or a glacier scratching a mountain, or an animal scratching soft rocks while digging.

Answer:

The two types of weathering are physical weathering (also called mechanical weathering) and chemical weathering.

Question 2