Science Assessment- Task 1-2026

Energy is a fundamental concept in science, defined by the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed or transferred.
Everyday examples of energy transformations include:
Chemical energy from food converted into kinetic energy during movement.
Electrical energy transformed into light and heat in a light bulb.
Although energy is conserved, some energy is often lost as heat, which reduces the efficiency of processes.

Kinetic Energy: The energy of movement, which can be observed in moving objects.
Potential Energy: Stored energy that has the potential to do work, such as energy stored in chemical bonds or elevated objects.

Electricity involves the movement of charged particles, primarily electrons.
Three key components of electricity:
Voltage (V): The amount of energy provided to charges.
Current (I): The flow of electric charge.
Resistance (R): The opposition to the flow of current.
Ohm’s Law (V = IR) describes the relationship between voltage, current, and resistance, indicating that increasing voltage increases current, while increasing resistance decreases current.

Electrical circuits can be arranged in two main configurations:
Series Circuits: Only one path for current to flow, where the total resistance is the sum of individual resistances.
Parallel Circuits: Multiple pathways for current, allowing for more reliable energy flow and reducing the total resistance.

Homeostasis is the process by which living organisms maintain stable internal conditions necessary for survival.
Key parameters regulated by homeostasis include body temperature, blood glucose levels, water balance, and pH.
Failure to maintain homeostasis can lead to illness or death.

Homeostasis operates through feedback loops:
Negative Feedback Loops: Most common type, reversing changes to maintain stability (e.g., sweating to cool down when body temperature rises).
Positive Feedback Loops: Amplify responses until a specific outcome is achieved (e.g., blood clotting or childbirth).

Homeostasis involves various physiological processes:
Thermoregulation: Control of body temperature through sweating and shivering.
Regulation of blood glucose levels by hormones:

The body detects and responds to changes through the stimulus-response model:
Stimulus: A change in the environment detected by receptors.
Receptors: Convert stimuli into electrical signals sent to the central nervous system.
Effectors: Muscles or glands that carry out responses.

The nervous system is responsible for fast, short-term responses using electrical impulses.
It consists of:
Sensory Neurons: Carry signals from receptors to the central nervous system.
Interneurons: Process information within the central nervous system.
Motor Neurons: Transmit signals to effectors.

Reflex actions are rapid, automatic responses that occur without conscious thought, controlled by the spinal cord through a reflex arc.
These reflexes are crucial for protecting the body from harm, such as withdrawing a hand from a hot surface.

The endocrine system controls slower, long-term processes through hormones, which are chemical messengers released by glands.
Key glands include:
Pituitary Gland: Master gland regulating other glands.
Thyroid Gland: Regulates metabolism.
Pancreas: Regulates blood glucose levels.

The nervous and endocrine systems work together to maintain homeostasis:
During exercise, the body increases heart rate and breathing rate to supply muscles with oxygen, while sweating helps regulate temperature.

Scientific investigations into biological processes rely on accuracy, reliability, and validity to draw meaningful conclusions.
Accuracy: How close results are to the true value.
Reliability: Consistency of results when experiments are repeated.

Validity: Refers to whether the experiment measures what it is intended to measure.
Ensuring these factors are met allows scientists to understand how the body maintains homeostasis and responds to environmental changes.