探索重力与空气阻力

Do children take and record readings accurately?  
Can they use findings to refute or support scientific ideas?  
Do they use scientific vocabulary?  
Can they describe how gravity pulls things towards Earth?  
Can they explain that air resistance slows falling objects, and therefore the surface area of an object affects their speed?

Quizzes available in pupil zone.

Unit knowledge organiser and test available in unit documents.

The Science Behind the Science:

Gravity is the force that keeps all planets within the solar system in orbit around the Sun. It also helps the moon to stay in orbit around the Earth too. Gravity is basically when objects that have mass are attracted to one another. Many people believe that it was Isaac Newton’s initial observation of the apple falling from the tree that inspired the theory around gravity. Albert Einstein later adapted this theory to his theory of relativity. 

Would you believe me if I said that every object has gravity in it? It’s just that some of these objects have a lot more gravity than others do. Can you think of one? Yes, the Sun. The Sun has a huge amount of gravity which explains why it can keep all planets in orbit around itself. This gravitational force keeps Earth at just the right position to allow us to get the necessary amount of light and warmth to survive. Gravity is proportional to how big an object is. For example, the larger an object is, the more gravity it has. This can be used to explain why the Sun has so much gravity.  

We need gravity to prevent us from flying off here and there. Gravity keeps us grounded to the floor. Do you remember the football example? If you kick a football, it goes flying in the air. This football would continue to fly if it was not for gravity. Gravity is what brings the ball back to the ground. Here’s a cool fact to remember: the tides that you see in the ocean are as a result of the moon’s gravity. 

Air resistance is the force that acts in the opposite direction to which an object is moving. So basically, air slows down things that are trying to or are already moving. Another word for air resistance is ‘drag’. The quicker you move, the bigger the resistance. A cool way to remember it is by taking into consideration what happens when you ride a bicycle. When you are pedalling fast, the air is also pushing back against your body. This is air resistance. If it is windy on your bike ride, it would be very difficult to pedal through the air as it is pushing back against you with a greater force. This is why you don’t see many cyclists on a windy day.