Science Assessment 3 Study Notes

Grade 6 – Gravitational Interactions and Fields


1. Gravitational Force

  • Gravity is an attractive force between objects that have mass.

  • Gravity pulls objects toward each other.

  • All objects with mass have gravity.

  • Gravity can act without objects touching.

  • Gravity can work in a vacuum, where there is little or no air.

  • When mass increases, gravitational force gets stronger if distance stays the same.

  • When distance increases, gravitational force gets weaker if mass stays the same.

  • Gravitational force is measured in newtons (N).

2. Mass and Distance

  • Mass is the amount of matter in an object.

  • Both objects' masses affect gravitational force.

  • Distance is measured between the centers of two objects.

  • More mass usually means stronger gravitational attraction.

  • More distance means weaker gravitational attraction.

  • Attraction means objects pull toward each other.

  • Repulsion means objects push away from each other.

3. Variables in an Investigation

  • Independent variable: The factor that scientists purposely change.

  • Dependent variable: The result that scientists measure.

  • Controlled variables: Factors that scientists keep the same.

  • Confounding variable: An extra factor that changes and makes it hard to know what caused the result.

  • A fair test changes only one independent variable at a time.

4. Repeated Trials

  • Repeated trials are when scientists test something more than once.

  • Repeating trials helps check if results are consistent.

  • Repeated trials show how much results can vary.

  • More trials can make results more trustworthy.

5. Graphs and Data

  • The x-axis shows the independent variable.

  • The y-axis shows the dependent variable.

  • A downward-sloping graph means the measured force gets weaker as distance increases.

  • A graph showing weaker force does not mean the force becomes repulsion.

  • Scientists should not make claims about distances they did not test.

6. Magnetic Fields

  • A magnetic field is an area where magnetic forces can affect objects.

  • Magnetic fields can act without touching.

  • A compass can detect a magnetic field.

  • A magnet can attract certain objects across an open gap.

  • The direction of a magnet can affect the results of an investigation.

7. Electric Fields

  • An electric field is an area where electric forces can affect objects.

  • Electric fields can act without objects touching.

  • A charged bead can be used to test an electric field.

  • Two positive charges repel each other.

  • Opposite charges attract each other.

  • A charged object can attract a neutral object.

  • A neutral object has no overall electric charge.

8. Reference Readings and Sensor Drift

  • A reference reading is a starting measurement used for comparison.

  • A baseline is another word for a reference reading.

  • Scientists compare results with a reference reading to see if something changed.

  • Sensor drift happens when a sensor's reference reading changes over time.

  • Scientists should check the sensor before and after testing.

  • If the sensor keeps changing, subtracting only the first reading might not fix the problem.

9. Detector Limits and Uncertainty

  • Every measuring tool has limits.

  • A detector limit is the smallest force a detector can reliably measure.

  • A reading of 0.00 N does not always mean there is no force.

  • It could mean the force is too small for the detector to measure.

  • A more sensitive detector can measure smaller forces.

  • Scientists should consider uncertainty when comparing results.

10. Making an Investigation Trustworthy

  • Change only one independent variable.

  • Keep controlled variables the same.

  • Repeat each trial.

  • Use the same equipment when possible.

  • Record measurements carefully.

  • Check the reference reading before and after testing.

  • Use a suitable test object.

  • Observe whether an object moves without touching the source.

11. Important Things to Remember

  • Gravity is always attractive.

  • More mass means stronger gravitational attraction when distance stays the same.

  • More distance means weaker gravitational attraction when mass stays the same.

  • A compass tests for magnetic fields.

  • A charged bead tests for electric fields.

  • Repeated trials help make results more trustworthy.

  • A fair test changes only one variable.

  • Sensor drift means the reference reading changes over time.

  • A zero reading does not prove that no force exists.