Scientific Investigations
A student want to measure the length of a toy car's path across the floor. What tool should the student use?
A meter stick or measuring tape
What type of energy does a soccer ball have while it is rolling across a field?
kinetic energy
What is a push or pull that can change an object's motion called?
a force
What are the two basic properties that all matter has?
has mass and takes up space
What process allows green plants to use light energy to make their own food?
Photosynthesis.
A student tests two types of soil to see which allows water to pass through faster. Name one thing the student should keep the same to make the test fair.
Keep the amount of soil, amount of water, container, or testing method the same. Only the soil type should change.
What type of energy is produced when a drumhead vibrates?
sound energy
What force causes a toy car rolling across carpet to slow down?
Friction
ice melts into liquid water. Is this a physical change or a chemical change?
A physical change. The substance remains water, although its state changes.
Name two important jobs that plant roots perform.
Roots absorb water and minerals and help anchor the plant in the soil.
A student repeats an experiment three times and gets similar results. Why is repeating an experiment helpful?
Repeating an experiment helps determine whether results are consistent and reduces the chance that a result was caused by an unusual occurrence.
A stretched rubber band is ready to be released. What type of stored energy does it have?
potential energy
A toy car travels 20 meters in 4 seconds. What is its average speed?
5 meters per second
A student mixes sand and iron filings. What tool can be used to separate the mixture?
A magnet. It attracts the iron filings but not ordinary sand.
In this food chain, which organism is the producer?
GRASS → GRASSHOPPER → FROG → SNAKE
Grass. It is the producer because it makes its own food using photosynthesis.
A student wants to determine whether water temperature affects how quickly sugar dissolves. What variable should the student change, and what should the student measure?
Change the water temperature and measure how long the sugar takes to dissolve. Keep the amount of sugar and water the same.
A lamp uses electrical energy and produces light and heat. What two forms of energy are produced?
light energy and thermal energy
Two identical balls roll down a ramp. One moves faster than the other. Which ball has more kinetic energy, and why?
The faster ball has more kinetic energy because the balls have equal mass and the faster ball is moving at a greater speed.
What happens to the particles of water when liquid water freezes into solid ice?
The particles become arranged in a more fixed structure and vibrate in place. They remain water particles.
A pond contains fish, frogs, algae, water, rocks, and sunlight. Name one living component and one nonliving component of this ecosystem.
Living components include fish, frogs, and algae. Nonliving components include water, rocks, and sunlight.
A student tests whether plants grow better in sunlight or darkness. The student uses different amounts of water for each group of plants. Why could this make the results unreliable, and how could the student improve the investigation?
Different amounts of water introduce another variable. Give both groups equal amounts of water and keep other conditions the same so light is the main variable being tested.
A student strikes a triangle instrument with a metal beater. The instrument vibrates and produces sound. What energy transformation occurs when the instrument is struck?
Kinetic energy from the moving beater is transferred to the instrument, causing vibrations that produce sound energy.
A student pushes a box to the right, but another student pushes it equally hard to the left. If the forces are balanced and the box starts at rest, what will happen to the box's motion? Explain.
The box will remain at rest because the forces are balanced and the net force is zero.
A student cuts paper into small pieces. Another student burns paper and observes smoke and ash. Which process is a physical change and which is a chemical change? Explain the difference.
Cutting paper is a physical change because it changes the size and shape without creating a new substance. Burning paper is a chemical change because new substances, including ash and gases, form.
In a meadow, the number of grasshoppers decreases greatly. Frogs eat grasshoppers, and snakes eat frogs. Predict one possible effect on the frog population and one possible effect on the snake population. Explain your reasoning.
Frogs may decrease because they have less food. Snake numbers may also decrease because less food is available if frog populations decline.