Students will have been aware of the effects of gravity since they first fell down, so it is probably the force they feel most familiar with. In this topic, they will extend their terrestrial experience to develop a much broader picture of the force of gravity, and its representation in the form of a gravitational field.
Students are often initially surprised by the fact that they pull up on the Earth with exactly the same force that the Earth pulls down on them. This topic will develop the idea that Newton’s Law of Universal Gravitation is precisely that: universal. Every single object with a mass in the universe gravitationally attracts every other object with mass.