physical and chemical change
What is a physical change?
A physical change is a change in the form or appearance of a substance without changing its chemical composition.
What is static electricity? What is human-harnessed electricity?
Static electricity is when electric charge builds up on something, like when you rub a balloon on your hair. Human-harnessed electricity is the kind we use in homes and buildings, coming from power plants and wires.
What is the difference between constructive and destructive processes, and how do they shape Earth's surface features?
Constructive processes build up Earth's surface by adding material, such as through deposition, volcanic eruptions, and mountain formation.
Destructive processes break down Earth's surface through erosion, weathering, and natural disasters like earthquakes.
These processes work together to constantly reshape landforms such as deltas, sand dunes, mountains, and volcanoes.
What is a microorganism?
A microorganism is a tiny living organism that can only be seen under a microscope. Examples include bacteria, fungi, protozoa, and viruses.
Why is it helpful for scientists to sort animals into groups like vertebrates and invertebrates?
Sorting animals helps scientists organize information and understand how animals are alike and different.
It also helps us study animals’ body structures, behaviors, and how they survive.
If you freeze water into ice and then melt it back into water, how do the properties of the substance change or stay the same?
The state of matter changes (solid to liquid and back), but the chemical composition of H₂O remains the same.
How do people use static electricity in real life? How do people use human-harnessed electricity?
Static electricity is used in printers and air purifiers. People use human-harnessed electricity to power homes, businesses, and technology like computers and phones.
Analyze how erosion and deposition work together to form a delta. How does this demonstrate both constructive and destructive forces?
Erosion breaks down rock and soil from land and carries it downstream through rivers.
As the river slows down near the mouth, deposition occurs, where sediment is dropped and accumulates, forming a delta.
This demonstrates destructive forces (erosion removing material) and constructive forces (deposition building up land).
Compare beneficial and harmful microorganisms.
Beneficial microorganisms help with processes like digestion, food production, and decomposition. Harmful microorganisms can cause diseases and spoil food. For example, E. coli can be harmful, while Lactobacillus is beneficial.
create a model (chart, poster, or slideshow) that shows how animals are sorted into vertebrates and invertebrates, and how vertebrates are sorted into 5 groups. Explain your choices.
Animal Classification Model
Explanation:
I sorted animals into two big groups first: vertebrates and invertebrates. Then I looked at the vertebrates and sorted them again based on body features. For example:
A frog goes in amphibians because it has moist skin and lives on land and water.
A parrot goes in birds because it has feathers and lays eggs.
A spider is an invertebrate because it does not have a backbone.
Explain why some substances dissolve in water while others do not.
Substances dissolve in water based on their molecular structure and polarity. Water is a polar molecule, meaning it dissolves other polar substances (like salt and sugar) but does not dissolve nonpolar substances (like oil).
What is the difference between a conductor and an insulator?
A conductor lets electricity flow, and an insulator stops electricity.
Construct an argument using scientific evidence to explain how a volcanic eruption can lead to both constructive and destructive changes to Earth's surface over time.
A volcanic eruption can be destructive because lava flows, ash clouds, and pyroclastic flows destroy ecosystems, homes, and landscapes.
However, over time, the cooling lava hardens and creates new landforms, such as islands, mountains, or rich volcanic soil that supports plant growth.
An example is the formation of the Hawaiian Islands, where repeated eruptions have built landmass over millions of years.
Explain how yeast is used in baking and why it's considered beneficial.
Yeast, a type of fungus, feeds on sugars and produces carbon dioxide gas, which helps dough rise. It’s beneficial because it makes bread light and fluffy and contributes to fermentation in food and beverage production.
Why is it important to understand the difference between inherited and acquired traits when learning about how living things grow and change?
Understanding the difference helps us know what traits we’re born with and what traits can change over time. This is important in science and health—like knowing if a disease runs in a family (inherited) or came from a person’s lifestyle (acquired). It also helps us see how organisms adapt to their environments.
If you mix flour and water, then let the water evaporate, what happens to the flour? What does this tell you about physical changes?
The flour remains after the water evaporates, showing that it was not chemically changed, only physically mixed with the water. This confirms that a physical change does not alter the substance's chemical identity.
Imagine you are designing a new way to use electricity. Would you use static or human-harnessed electricity? Why?
I would use human-harnessed electricity because it is more reliable and can power machines for a long time. Static electricity cannot provide steady energy, so it would not be good for running appliances.
Develop a hands-on experiment or simulation to model how a river changes the landscape over time. What variables would you manipulate, and how would you ensure your data accurately reflects real-world processes?
Experiment: Create a stream table using a sloped tray, sand, and flowing water to simulate river erosion and deposition.
Variables: Adjust water speed, volume, or sediment type to observe different erosion rates.
Data accuracy: Record sediment movement, measure changes in the land, and compare results to real river systems.
Explain how the structure of a plant cell supports its function in a plant's survival.
The cell wall provides rigid structure for support and helps the plant stand upright. Chloroplasts allow the plant to perform photosynthesis, creating energy. The large central vacuole (not explicitly in the standard, but often present) stores water and helps maintain pressure inside the cell.
Create a chart that compares the physical traits of a child and their parent(s). Label each trait as inherited or acquired. Then, explain how knowing which traits are inherited helps scientists or doctors learn about health and development.
Trait Parent Child Inherited or Acquired
Eye Color Brown Brown Inherited
Hair Texture Curly Curly Inherited
Tattoo Yes No Acquired
Height 5’10" 4’6” Inherited (potential)
Scar on knee Yes No Acquired
Develop a step-by-step procedure for separating a mixture containing sand, salt, and iron filings. Justify why you chose each separation method and how it demonstrates physical changes.
Step 1: Use a magnet to remove the iron filings (magnetism).
Step 2: Add water to the sand and salt mixture. The salt will dissolve while the sand remains.
Step 3: Use filtration to separate the sand from the saltwater solution.
Step 4: Evaporate the water to retrieve the salt.
Plan an experiment to test if different objects are conductors or insulators. What materials will you need? What steps will you take?
Gather materials: battery, wires, light bulb, different objects (penny, rubber band, paperclip, plastic spoon).
Connect the circuit with the battery, wires, and light bulb.
Test each object by placing it in the circuit.
Observe if the light bulb turns on (conductor) or stays off (insulator).
Record the results and classify each material.
If you were a city planner, what questions would you ask to determine the best technology to use in reducing the impact of coastal erosion? How would you evaluate the effectiveness of different solutions?
Questions:
What areas are most at risk for coastal erosion?
What natural and man-made factors contribute to erosion?
What technologies (e.g., seawalls, beach nourishment, artificial reefs) are most effective in similar environments?
Evaluation:
Compare before-and-after images using satellite data.
Measure changes in coastline over time.
Assess costs, environmental impact, and long-term sustainability of solutions.
Design and create a 3D model or digital animation comparing the structures and functions of plant and animal cells. Explain the significance of each labeled part.
Nucleus: Controls cell activities (both).
Cell membrane: Regulates materials entering/exiting (both).
Cytoplasm: Holds organelles and supports reactions (both).
Cell wall: Adds support and structure (plant only).
Chloroplasts: Site of photosynthesis (plant only).
How is an inherited trait different from an acquired trait? Can you give an example of each?
nswer:
Difference: Inherited traits come from your parents and are present at birth. Acquired traits are gained after birth through experience or environment.
Example:
Inherited trait: Naturally curly hair
Acquired trait: A pierced ear