Lesson focus: fieldThe area around something where it can push or pull another object without touching, like around a magnet. describe gravitational, magnetic and electrostatic interactions across distance.
Compare attraction, repulsionA pushing force that moves things apart, like two magnets pushing away. and material response for three non-contact forceA push or a pull, measured in newtons (N)..
Build on earlier learning
Introduction to forcesExtend force interactions to cases without contact.
You will be successful when you can…
- Name three non-contact forces.
- State gravity is attractive.
- Predict pole/charge interactions.
- Identify magnetic materials accurately.
Words that carry the science
- field
- Region in which an object can experience a non-contact force.
- gravity
- Attractive interaction between masses.
- magnetic force
- Interaction involving magnets and magnetic materials.
- electrostatic force
- Interaction between electrically charged objects.
- repulsion
- Forces pushing interacting objects apart.
Compare sources and possible directions
01Gravity
Every mass produces a gravitational fieldThe area around something where it can push or pull another object without touching, like around a magnet.. Between ordinary masses, gravityThe force that pulls objects towards each other, such as the Earth pulling you down. is attractive.
02Magnetism
Like magnetic poles repel; unlike poles attract. Iron, nickel and cobalt respond strongly; not every metal is magnetic.
03Electrostatics
Like charges repel and unlike charges attract. Both gravity and electrostatic forces are non-contact forcesForces that act without the objects touching, such as gravity, magnetism and the push or pull between electric charges.: they act without touching. The difference: gravity acts between massHow much matter (stuff) is in an object, measured in grams (g) or kilograms (kg); it stays the same wherever the object is, unlike weight. and only pulls (attracts). Electrostatic forces act between chargesPositive or negative electric charge that objects can carry; opposite charges attract and like charges repel. and can pull or push (attract or repel). Neutral objects can sometimes be attracted through charge rearrangement.
Forces at a distance
Magnetic, electrostatic and gravitational forces act without touching. They get weaker quickly as the objects move apart. Each object pulls (or pushes) the other with an equal and opposite force.
Controls
Forces are illustrative; the inverse-square pattern is right for charges and for gravity. Gravity only ever attracts.
Classify an interaction
A charged balloon attracts a neutral wall.
- No contact is needed initially.
- The balloon’s electric field rearranges charge slightly in the wall.
- Nearer opposite charge gives net attraction.
- This is electrostatic, not magnetic.
How to make the reasoning visible: Use source evidence rather than “pulls without touching”.
Field comparison
Complete the source and direction.
| Interaction | Source/test objects | Attract? | Repel? |
|---|---|---|---|
| Gravity | Masses | Yes | No for ordinary matter |
| Magnetic | Magnets/poles | Unlike poles | Like poles |
| Electrostatic | Charges | Unlike charges | Like charges |
| Magnet + iron | Magnet and iron | Usually | Not as a simple pole rule |
Why is aluminium not automatically attracted strongly to a bar magnet?
Why might an object not move despite field force?
Use the table. Give one way magnetic and electrostatic forces are similar.
Check your understanding
Answer from memory, then check against the suggested answer.
What is field?
What is gravity?
What is magnetic force?
What is a non-contact force?
What happens when two north poles are brought together?
Two positively charged objects are released. Predict.
Compare all three fields in one sentence each.
Why does a ball thrown upwards always come back down?
Exam Question Practice
Exam Question Practice
Mark points shown after marking
Answer the parts to compare gravitational forces and electrostatic forces.
Give one way the two forces are the same.
(1)Gravity acts between masses. What do electrostatic forces act between?
(1)Can gravity push things away, or can it only pull them together?
(1)What about electrostatic forces?
(1)Total for this question: 4 marks
Command word: For compareA command word: say how two or more things are similar and how they are different., give one way they are the same and some ways they are different. Use “both” and “but”.