Science skills

Science and Mathematics Notes

Accuracy: How close a measurement is to the true value.
Precision: How close multiple measurements are to each other, indicating a small spread of data.
Repeatable: An investigation is repeatable if the same person can repeat it and get the same results.
Reproducible: An investigation is reproducible if another person can repeat it and get the same results.
Anomalies: Values in a set of data that do not fit the observed pattern.

Continuous Data: Data that can be given any numerical value within a range. Examples include measurements like time, length, or speed.
Discontinuous Data: Data that can only take specific, separate values. Examples include the number of items (e.g., shrimp) or categories (e.g., plant names).

Independent Variable: The variable that you change in an experiment. It is typically plotted on the x-axis of a graph.
Dependent Variable: The variable that you measure in an experiment. It is typically plotted on the y-axis of a graph.
Control Variable: A variable that you keep the same throughout an experiment to ensure that only the independent variable is affecting the dependent variable.

Aim: To investigate how the number of turns in a coil affects the strength of an electromagnet.
Apparatus: Power pack, ammeter, variable resistor, insulated conducting wire, crocodile clips, iron core, paper clips.
Safety: Do not touch the wire; turn off the power between readings. Do not set up near water.
Graph: A line graph with the number of turns on the x-axis and the number of paper clips picked up (indicating magnetic strength) on the y-axis. Expect a positive correlation.
Variables:
- Independent: Number of turns in the coil of wire.
- Dependent: Number of paper clips picked up by the magnet.
- Control: Same amount of voltage/current, same wire type.

Aim: To investigate how the length of a wire affects the resistance in a circuit.
Equations: Resistance (ΩΩ) = Voltage (V) / Current (A)
Apparatus: Power supply, leads, crocodile clips, meter ruler, wire, fixed resistor, ammeter, voltmeter.
Safety: Do not touch the wire due to heat. Keep voltage low to prevent overheating of delicate components.
Graph: A line graph with length of wire (cm) on the x-axis and resistance (ΩΩ) on the y-axis. Expect a positive correlation.
Variables:
- Independent: Length of wire (cm).
- Dependent: Voltage (V) and Current (A), used to calculate resistance (ΩΩ).
- Control: Type of wire, same power supply.

Aim: To investigate how variables affect the speed of a toy car.
Equations: Speed (m/s) = Distance (m) / Time (s)
Apparatus: Metre ruler, trolley, ramp, blocks (to adjust ramp height), stopwatch, something to catch the trolley.
Safety: Clear the track of trip hazards. Use a car made of safe material.
Graph: A line graph with the height of the ramp (cm) on the x-axis and the speed (m/s) of the car on the y-axis.
Variables:
- Independent: Height of the ramp (cm).
- Dependent: Time taken for the car to travel down the ramp (s). (Note: Speed is calculated from this, so it's indirectly dependent).
- Control: Length of the ramp, type of car.

Aim: To investigate how the characteristics of a falling asteroid affect the size of the crater formed.
Apparatus: Tray with sand, ball bearing(s), metre ruler, clamp stand.
Safety: Clean up sand to prevent trip hazards. Do not throw or dangerously handle balls.
Graph: A line graph with the mass or height of the ball on the x-axis and the diameter or depth of the crater on the y-axis.
Variables:
- Independent: Mass or height of the ball.
- Dependent: Size of the crater (e.g., diameter or depth).
- Control: Height or mass (whichever is not the independent variable) and the method of dropping the ball.

Aim: To investigate changes in mass when copper carbonate and magnesium are heated.
Copper Carbonate Heating:
- Apparatus: Eye protection, heating apparatus (Bunsen burner, heat-proof mat), clamp, boss & stand, boiling tube, spatula, electronic balance, copper carbonate.
- Safety: Wear eye protection. Ensure the open end of the boiling tube points away from people. Wash hands afterwards. Take care with the hot apparatus.
Magnesium Heating:
- Apparatus: Eye protection, heating apparatus (Bunsen burner, heat-proof mat, tripod), pipe clay triangle, tongs, crucible with lid, emery paper, magnesium ribbon.
- Safety: Wear eye protection. Use tongs to handle apparatus. Wash hands afterwards. Do not look directly at burning magnesium.

Aim: To test the hypothesis that the volume of carbon dioxide produced by respiring yeast depends on the temperature.
Apparatus: 3 measuring cylinders, bread flour, dried yeast, large beaker, stirring rod, sugar, spoon, water, clock, thermometer, water bath.
Safety: Do not eat the dough. Wear eye protection.
Graph: A line graph with temperature (°C) on the x-axis and the change in volume of gas (cm3cm3) on the y-axis.
Variables:
- Independent: Temperature (°C).
- Dependent: Change in volume of gas (cm3cm3).
- Control: Amount of dough, time spent in the water bath.

Explosive: Indicates a substance that can explode under certain conditions.
Flammable: Indicates a substance that can easily catch fire.
Corrosive: Indicates a substance that can damage materials or living tissue.
Acute Toxicity: Indicates a substance that can cause harm or death if inhaled, swallowed, or absorbed through the skin.
Health Hazard: Indicates a substance that can cause long-term or serious health effects, such as carcinogenicity or respiratory sensitization.
Hazardous to the Environment: Indicates a substance that can harm aquatic life or the environment.
Oxidising: Indicates a substance that can cause or contribute to the combustion of other materials.

R=VIR=IVWhere:

Speed=DistanceTimeSpeed=TimeDistanceWhere:

a=ΔvΔta=ΔtΔvWhere: