Wave Properties & Signals
What are the three possible things that can happen to a light wave when it hits a material?
Reflection, absorption, transmitted (or transmitted/refraction).
What process do plants use to turn sunlight into chemical energy?
Photosynthesis.
What is competition between organisms? Give a short example.
Competition: organisms vie for the same limited resource (e.g., two plants for sunlight).
Name two factors that cause seasons on Earth.
Earth’s tilt and its orbit around the sun (or rotation relative to the sun).
What is a constraint in the engineering design process? Give one classroom example.
A limit on the design (e.g., time, materials, size). Classroom example: only using recycled materials.
Define amplitude and explain how amplitude relates to the energy in a wave.
Amplitude = height of wave; larger amplitude means more energy.
What molecule produced by photosynthesis stores energy for plants to use?
Glucose (or sugar).
Name and define one type of symbiotic relationship besides competition.
Mutualism (both benefit), commensalism (one benefits, other unaffected), parasitism (one benefits, other harmed).
What causes a solar eclipse?
When the Moon passes between the Sun and Earth, blocking sunlight.
When evaluating two design solutions, name one criterion you might use to decide which is better.
Criteria example: durability, cost, effectiveness, safety.
What is the difference between reflection and refraction of light?
Reflection: bounces off a surface; Refraction: bends when entering a different medium.
Draw or describe a simple food chain that starts with the sun and includes a producer, a primary consumer, and a secondary consumer.
Sun → Grass (producer) → Rabbit (primary consumer) → Fox (secondary consumer).
How might limiting resources affect the population size of a species?
Limiting resources (food, water, space) can reduce birth rates or increase death rates, lowering population size.
What two forces control the regular motion of planets and other celestial bodies?
Gravity and inertia (or motion/centripetal forces).
Describe a simple test you could run to compare two designs for a prototype (what data would you collect?).
Test run: measure time to complete task, count failures, measure distance/temperature; collect quantitative data like time (s) or temperature (°C).
Give one example of a material that mostly absorbs light and one that mostly transmits light.
Absorb: black cloth; Transmit: clear glass.
On an energy pyramid, does the amount of available energy increase or decrease as you move from producers to top predators? Explain why.
Decrease — energy is lost at each level (heat, metabolism), so less is available higher up.
Describe one example of a predator–prey relationship and how it helps maintain ecosystem balance.
Example: wolves (predator) and deer (prey); predation controls deer numbers and prevents overgrazing
Give one way the Earth’s moon is different from Earth (size, surface, atmosphere, or ability to support life).
Moon is smaller, has many craters, and no atmosphere; cannot support life like Earth.
Explain how combining the best characteristics of different designs can lead to a better final solution.
By identifying best traits (e.g., lightweight from Design A, durable from Design B) you combine them to meet criteria better.
Explain why digital signals are often more reliable than analog signals for sending information.
Digital encodes discrete values (bits) so noise/errors are easier to detect and correct; analog varies continuously and is more affected by noise.
Explain how photosynthesis connects to respiration in the flow of energy through ecosystems.
Photosynthesis captures solar energy in glucose; respiration releases that stored chemical energy for organisms to use.
Construct a brief argument (1–2 sentences) that changing a physical component (like water availability) can affect populations, using evidence or reasoning.
Example argument: If water availability drops, plant growth declines (data: lower biomass), causing herbivore populations that depend on those plants to decrease.
Describe how Earth’s tilt and orbit result in different daylight hours at different times of year.
Tilt changes the angle sunlight hits different hemispheres during orbit, changing day length and intensity of sunlight.
Define criteria and constraints for a small project: design a device that reduces heat loss from a model “house” (list at least three criteria or constraints).
Example criteria/constraints: keep inside temperature within 2°C of target, use only materials provided, cost under $10, safe for students.