Investigating Science Flash Cards ALL

What are systematic errors?

Errors that occur systematically (e.g. every test, every 2nd or 3rd test), usually due to instrument calibration issues or consistent environmental influences. They affect the accuracy of measurements, leading to bias in results.

What are random errors?

Errors that arise unpredictably in measurements, often due to limitations in the measurement process or environmental variations. They affect the precision of results but not the overall accuracy.

Sample Size

The number of observations or replicates included in a statistical sample, which influences the reliability and validity of results in an experiment.

Sample Selection / Types

Probability Sampling
Random	Equal chance for all
Systematic	Every nth person selected
Stratified	Random selection within categories
Non-Probability Sampling
Convenience	Chosen due to ease of access
Snowball	Referrals from participants
Quota	Targets people with specific traits

Poor selection of sample can lead to sample bias.

Accuracy

Use precise equipment, calibrate instruments, and record consistent measurements.

Reliability

Repeat experiments, compare findings, and check for consistency.

Validity

Use control groups, control variables, and directly test the hypothesis.

Aim

The goal of the experiment and must include variables (e.g. To find whether increasing weight in water increases speed of falling in water).

Variables

Independent Variable (Constant), Controlled Variable (Confounding factors that need to be controlled), Dependent Variable (Variable being measured e.g. Speed of a reaction)

Hypothesis

The prediction of the experiment (Must be a statement).

Where should IV and DV be on a graph?

The independent variable (IV) should be plotted on the x-axis, while the dependent variable (DV) is plotted on the y-axis.

What is the definition of a scientific fact?

A basic statement established by experiment or observation. All facts are true under specific conditions. Some facts may be false when re-tested with better instruments.

What is the definition of a scientific law?

Scientific laws describe natural phenomena that consistently occur under the same conditions, often expressed mathematically.

What is the definition of a hypothesis?

A tentative statement such as ‘if A happens then B must happen’ that can be tested by direct experiment or observation. The statement has yet to be proven but can lead to scientific laws or theories.

What is the definition of a scientific theory?

An explanation for why certain laws and facts exist that can be tested to determine its accuracy.

What is the definition of a belief?

A statement that is not scientifically provable in the same way as facts, laws, hypotheses or theories. Scientifically disproven beliefs can still be held to be true.

What is the law of Refraction?

Light or other waves bend when passing from one medium to another.

What is the law of Reflection?

When a light ray (or any wave) reflects off a smooth surface, the angle of incidence (the angle between the incoming ray and the surface's normal line) is equal to the angle of reflection.

What’s a microscope?

Convex lenses magnify small, close objects

What is a Refracting Telescope?

Refracting telescopes have large lens at the front (objective lens) and an eyepiece. They produce high-contrasting images, uses sealed tube to keep out dust and requires little maintenance. However expensive, heavy and long, and can only be supported at the edges, limiting size.

What is a reflecting telescope?

Reflecting telescopes use primary concave mirrors (collects light) and a secondary mirror (to redirect light to eyepiece or camera). Cheap and easy to make, however requires cleaning and maintenance such as fixing alignment of mirrors and dusting.

What is a radio telescope?

Uses a parabolic dish to reflect wavelengths to focal receiver in space.

What is an unstable atom?

An imbalance of protons and neutrons.

What is a radioisotope?

An unstable element emitting radioactivity,

What is radioactive decay?

The emission of radioactivity from unstable atoms.

What types of radioactivity are there and what’s their penetration level?

Alpha (α): Low penetration
Beta (β): Medium penetration

Gamma (γ): High penetration

What is ionisation?

Ionization is the gain or loss of electrons. The loss of electrons, which is the more common process in astrophysical environments, converts an atom into a positively charged ion, while the gain of electrons converts an atom into a negatively charged ion.

What does a Geiger-Muller Counter do?

Radiation ionises gas → creates current → counts as a click. GMC counts click

What is Half-life?

The time taken for the radioactivity of a specified isotope to fall to half its original value.

What is EBT (External Beam Therapy)?

EBT is a type of radiotherapy, it uses LINAC to target tumor with electron beams, sparing healthy cells

Brachytherapy

Radioactive seeds implanted directly near tumor (permanent or temporary)

What is nuclear fission?

Heavy nucleus splits, triggers chain reaction causing boom

What is nuclear fusion?

Light nuclei combine under extreme pressure/heat causing bigger boom

How does a hydrogen bomb work?

It uses fission to trigger fusion using deuterium