Sc EYE revision

Flashcards

What is a hypothesis?

A proposed explanation for an observation that can be tested scientifically.

What should you do if experimental results do not support a hypothesis?

Revise the hypothesis to form a new one.

What is the independent variable?

The part of the experiment that you deliberately change.

What is the dependent variable?

The quantity you measure or observe.

What is a constant variable (control variable)?

A factor kept the same throughout an experiment to ensure a fair test.

What is the SI unit for time?

Second (s).

What is the SI unit for mass?

Kilogram (kg).

What is the SI unit for length?

Metre (m).

What is the SI unit for temperature?

Kelvin (K).

What is the SI unit for volume commonly used in physics?

Cubic metre (m³).

What is accuracy?

How close measurements are to the true value.

What is precision?

How close repeated measurements are to each other.

What is zero error?

An instrument reading that is not zero when the quantity is zero.

How can zero error be corrected?

By using tare or adjusting zeros as appropriate (e.g., pressing tare).

What is parallax error?

Error caused by viewing a scale from an angle rather than perpendicularly.

What is the correct way to read a ruler?

Keep your eyes perpendicular to the markings.

What is the correct way to read a measuring cylinder?

Read at the bottom of the meniscus.

What is the correct way to read a thermometer?

Level with the top of the meniscus for the given setup.

What is qualitative data?

Data collected using senses and non-numerical observations.

What is quantitative data?

Data that uses numerical values.

What is the goal of science?

To explain phenomena and test hypotheses.

What is a scientific theory?

A well-supported explanation that can be revised with new evidence.

What is melting point?

The temperature at which a solid changes to a liquid.

What is electrical conductivity?

The ease with which an electric current flows through a material.

What is thermal conductivity?

The ease with which heat flows through a material.

What is density?

Mass per unit volume; density = mass ÷ volume.

What is hardness?

A material's resistance to wear and scratches.

What is the purpose of the water displacement method?

To measure the volume of an irregular object by the change in water level when submerged.

How do you calculate volume using water displacement?

Final water volume minus initial water volume after submerging the object.

Why is a sinker used in density experiments?

To ensure the object is fully submerged for an accurate volume measurement.

What is the formula for density?

Density = mass ÷ volume.

What is the purpose of a digital caliper?

To measure internal and external diameters (and depth) with high precision.

What does the air hole on a Bunsen burner control?

Regulates air intake to adjust flame type and temperature.

What is the difference between a luminous and a non-luminous flame?

A luminous flame is yellow/orange and cooler; a non-luminous flame is blue and hotter.

What is the periodic table used for?

To identify and predict trends in the properties of elements.

What is a compound?

Two or more elements chemically combined in fixed proportions.

What is a mixture?

Two or more substances not chemically combined in fixed ratios; can be separated by physical methods.

What is a solute?

Substance dissolved in a solvent.

What is a solvent?

Substance that dissolves the solute.

What is concentration?

Amount of solute dissolved in a given amount of solvent.

What factors affect the rate of dissolving?

Stirring, particle size, temperature, and amount of solvent.

What is filtration?

A separation technique that uses filter paper to retain insoluble solids while letting liquid pass.

What is evaporation?

Separates a soluble solid by evaporating the solvent, leaving the solute behind.

What is distillation?

Separates liquids with different boiling points by heating and condensing the vapor.

What is magnetic separation?

Separates magnetic substances using magnets.

What is a suspension?

A mixture in which insoluble particles are dispersed; light is scattered and may not pass through completely.

What is dispersion of white light?

Splitting white light into its component colors (red to violet) due to different refractions.

What is refraction?

Bending of light when it passes between media with different optical densities.

What is the main idea of the ray model of light?

Light travels in straight lines; rays reflect, and images form according to reflection rules.

What is a concave mirror?

A mirror that curves inward; can magnify and form real or virtual images depending on distance.

What is a convex mirror?

A mirror that curves outward; typically produces a virtual, upright, reduced image.

What is meant by regular vs irregular reflection?

Regular reflection produces a clear image (smooth surfaces); irregular (diffuse) reflection scatters light.

What happens to light when moving from a rarer to a denser medium?

It slows down and bends toward the normal.

What happens to light when moving from a denser to a rarer medium?

It speeds up and bends away from the normal.

What is the visible spectrum?

The range of colors visible to the human eye (red, orange, yellow, green, blue, indigo, violet).

What is the job of the cell membrane?

A partially permeable layer that controls the movement of substances into and out of the cell.

What is the nucleus?

Controls all cellular activities and contains DNA.

What is cytoplasm?

The site of most chemical reactions in the cell.

What is a plant cell’s central structure that stores water?

Large central vacuole.

What is the plant cell wall?

A rigid layer that provides shape and support (absent in animal cells).

Do animal cells have chloroplasts?

No, animal cells do not have chloroplasts.

Do animal cells have a cell wall?

No, animal cells do not have a cell wall.

What is microscopy used for?

To magnify an object and observe tiny structures not visible to the naked eye.

What is the typical sequence for preparing a slide for microscopy?

Prepare a thin tissue layer, add stain (e.g., iodine), place on slide, remove air bubbles, focus with knobs.

What is a microscope’s stage used for?

To hold the slide in place.

What is a common method to identify the atomic structure?

Atoms are composed of protons, neutrons, and electrons; protons determine the element’s identity.

What does an atom’s mass number represent?

The total number of protons and neutrons in the nucleus.

What does the atomic number represent?

The number of protons in the nucleus (defines the element).