science study

Major steps of the scientific method

1. Make observations 2. Formulate a question 3. Develop a hypothesis 4. Conduct experiments 5. Analyze data 6. Draw conclusions

Qualitative observation

An observation that describes qualities or characteristics without using numbers.

Quantitative observation

An observation that involves measurement or quantities and is expressed numerically.

Proper hypothesis format

If [independent variable], then [dependent variable], because [explanation of reasoning].

Independent variable

The variable that is changed or controlled in an experiment to test its effects on the dependent variable.

Dependent variable

The variable that is measured and affected in the experiment.

Constant

A factor that remains the same throughout the experiment.

Control group

The group that does not receive the experimental treatment and is used for comparison.

Experimental group

The group that receives the treatment or condition being tested.

Importance of a control group

A control group is necessary to establish a baseline and compare the effects of the independent variable.

Major problem in experimental design

The lack of random assignment or insufficient sample size; it could be improved by randomizing subjects or increasing participants.

Scientific theory

A well-substantiated explanation of an aspect of the natural world, based on a body of evidence.

Scientific law

A statement based on repeated experimental observations that describes some aspects of the universe.

Laboratory safety

Always read instructions and ensure the workspace is clear before starting any laboratory investigation.

Steps to follow after breaking glass

1. Notify the teacher immediately. 2. Carefully clean up the broken glass using a broom and dustpan.

Action in case of fire on clothing

Stop, drop, and roll to extinguish the flames and use a fire blanket if available.

P.A.S.S. acronym meaning

P: Pull the pin, A: Aim at the base of the fire, S: Squeeze the handle, S: Sweep from side to side.

Best equipment for measuring liquid volume

Graduated cylinder.

Best equipment for holding liquids while heating

Beaker.

Best equipment for moving hot beaker

Beaker tongs.

Meniscus in graduated cylinder

The curved surface of a liquid in a cylinder; the volume should be read at the bottom of the meniscus.

SI Unit for Mass

Kilogram (kg).

SI Unit for Length

Meter (m).

SI Unit for Temperature

Kelvin (K).

SI Unit for Time

Second (s).

Average calculation for Group A

Average = (26.5 + 27.5 + 27.0 + 27.7) / 4 = 27.175 cm.

Average calculation for Group B

Average = (25.5 + 25.0 + 23.0 + 29.5) / 4 = 25.25 cm.

More precise measurements in groups

Group A is more precise because the measurements are closer together.

More accurate measurements in groups

Group A is more accurate overall because its average is closer to the actual length of 26.1 cm.

Difference between accuracy and precision

Accuracy refers to how close a measurement is to the true value, while precision refers to how consistent multiple measurements are.

Conversion to scientific notation

78,900,000,000 = 7.89 × 10^{10}.

Conversion to scientific notation

0.00410 = 4.10 × 10^{-3}.

Conversion to standard notation

1.17 × 10^{-4} = 0.000117.

Conversion to standard notation

9.081 × 10^{7} = 90,810,000.

Metric conversion setup for kg to g

45 kg × 1000 g/kg = 45000 g.

Metric conversion setup for cm to hm

2570 cm × 0.001 hm/cm = 0.0257 hm.

Temperature conversion to Kelvin

K = °C + 273.15; 58°C = 58 + 273.15 = 331.15 K.

Temperature conversion to Fahrenheit

°F = (°C × 9/5) + 32; °F = (29 × 9/5) + 32 = 84.2 °F.

Difference between distance and displacement

Distance is the total path length covered, while displacement is the shortest straight-line distance from start to end point.

Runner's distance and displacement

a. Distance = 400 m; b. Displacement = 0 m; c. Because the runner returned to the starting point.

Average speed calculation

Average Speed = Distance / Time = 5.20 m / 10.4 s = 0.5 m/s.

Train travel distance calculation

Distance = Speed × Time = 227 km/hr × 2.0 hr = 454 km.

Car's velocity calculation

Velocity = Distance / Time; Velocity = 240 km / 4 hr = 60 km/hr west.

Student's total distance traveled

Total Distance = 3.0 miles + 2.0 miles = 5.0 miles.

Student's displacement calculation

Displacement = √(3.0² + 2.0²) = √(13) ≈ 3.6 miles.

Car's acceleration calculation

Acceleration = (Final velocity - Initial velocity) / Time = (65 m/s - 30 m/s) / 3.5 s = 10 m/s².

Go-cart's final velocity calculation

Final velocity = Initial velocity + (Acceleration × Time) = 32 m/s + (-1.5 m/s² × 10.8 s) = 32 - 16.2 = 15.8 m/s.