8th grade Science EOG Review Part 1

Front

What is a chemical change?

Back

A chemical change is a process where substances combine or break apart to form new substances with different properties. Example: A cake baking is a chemical change because it transforms ingredients into a new product.

Front

What evidence supports the theory of evolution?

Back

Evidence from rock layers, fossils, and ice cores supports the theory of evolution by showing how life forms have changed over time.

Front

How can genetic variation in a population be increased?

Back

Genetic variation can be increased by an increase in mutations, which introduce new traits into a population.

Front

What is a compound?

Back

A compound is a substance formed when two or more elements chemically bond together. Example: Sugar (C12H22O11) is a compound made of carbon, hydrogen, and oxygen.

Front

Why do scientists study ice cores?

Back

Scientists study ice cores to understand past climates by analyzing the trapped air bubbles and layers of ice.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change alters the form of a substance but not its chemical composition (e.g., crumpling paper), while a chemical change results in the formation of new substances (e.g., baking a cake).

Front

What is the role of fossils in understanding evolution?

Back

Fossils provide evidence of past life forms and their changes over time, helping scientists understand the process of evolution.

Front

What is genetic mutation?

Back

A genetic mutation is a change in the DNA sequence of an organism, which can lead to new traits and increased genetic diversity.

Front

What are the main components of air?

Back

Air is primarily composed of nitrogen (78%), oxygen (21%), and small amounts of other gases like carbon dioxide and argon.

Front

What is the significance of tree rings?

Back

Tree rings can provide information about the age of a tree and past climate conditions, as each ring represents a year of growth.