Science Grade 7 Final Review

What types of organisms can create their own food?

What types of organisms can create their own food?

Plant organisms

What is the difference between a physical and chemical change? Give examples.

Physical Change - A physical change is when something changes how it looks or feels, but what it's made of stays the same. (Melting) Chemical - Any change that changes matter into a new substance (Burning Wood)

What is an organic compound? List 4 categories of organic compounds.

An organic compound is a compound that contains carbon and hydrogen. 

• Lipids

• Carbohydrates 

• Proteins 

• Nucleic Aid 

What are 3 differences between animal and plant cells?

1. Plant cells have a cell wall and animals do not. 

2. Plants produce glucose through the chloroplast and animal cells do not 

3. Plant cells are boxier while animal cells are rounder

Nucleus

Holds DNA; gives direction to the cell

Cell Wall

A rigid layer that surrounds plant cells only 

Provides Protection and Support

Cell Membrane

Boundary Layer that controls what substances go in and out of the cells

Cytoplasm

Gel-like liquid that contains all the structures needed for the basic life structures of the cell

Mitochondria

Powerhouse of the cells

Ribosomes

Ribosomes are tiny structures found in cells that help in the production of proteins.

Chloroplast

Use sunlight to create food

What is the connection between fossil fuels, the greenhouse effect, and climate change?

When fossil fuels get burned, they release carbon dioxide. Carbon dioxide is a greenhouse gas that traps heat in the atmosphere, causing global warming.

What are some impacts of climate change?

Climate change causes hotter temperatures, melting ice, and rising sea levels.

How can we slow down the rate of climate change?

We can slow down climate change by using renewable energy sources like solar and wind, and by reducing our use of fossil fuels.

What is a renewable resource? Give examples?

A renewable resource is something that can be used repeatedly and doesn't run out because it is naturally restored.. Examples include sunlight, wind, and water.

What is a nonrenewable resource? Give examples.

A nonrenewable resource is a natural resource that cannot be replaced once it is used up. Examples include coal, oil, and natural gas.

Explain the direction in which heat transfers between objects of different temperatures and identical temperatures

Heat always transfers from a warmer object to a cooler one until both objects reach the same temperature. When two objects have identical temperatures, there is no heat transfer between them because they are in thermal equilibrium.

What type of energy transfer takes place when you turn on a toaster?

When you turn on a toaster, the type of energy transfer that takes place is electrical energy being converted into heat energy.

What are the differences between rotation and revolution? (At least 3)

Rotation: 24 hours, causes day and night, earth spinning on its aix

Revoltuion: 365.25 days, causes seasons and its earth’s movement around the sun

What causes day and night?

Rotation

What causes seasons?

Revolution

What is the Moon? Why do we see it?

The Moon is Earth's natural satellite, orbiting around our planet. We see the Moon because it reflects light from the Sun.

What causes the Moon’s phases?

The cause of the Moon phases is It’s orbit around the Earth

How long does it take for the Moon to go from one Full Moon to the next?

It takes 29.5 days to go from one Full Moon to the next.

What causes eclipses?

Eclipses occur when the Earth, Moon and sun align in different ways.

Is light matter? Explain.

Light is not considered matter because it doesn't have mass or take up space like solids, liquids, and gases do. Instead, it's a type of energy that travels in waves.

How are light waves different from sound waves?

Light waves travel fastest in gasses while sound waves travel fastest in solids.

What is the relationship between frequency & wavelength?

As frequency increases, wavelength decreases.  As wavelength decreases, frequency increases.

What is the relationship between energy & amplitude?

As energy increases, amplitude increases.

What are the differences between reflection, refraction, transmission and absorption?

Reflection: The bouncing back of an object after it strikes matter Refraction: Changing direction or bending of a wave passing from one medium to another Transmission: When something moves from one place to another Absorption: the transfer of energy from a wave to matter as the wave passes through it;