Fantastic Forces

What To Do

Introduction

If you have a skateboard, you could bring it in for this introduction.

• Ask for two volunteers.
  • Ask one student to sit cross-legged on the floor (carpeted area works best, but any floor is fine).
  • Ask the seated student if it’s OK if the second student pushes on their back – I’ve never had a student say “no”, but I think it’s polite to ask permission.
• Instruct the second student to try to move/slide the seated student across the floor by pushing (not too hard) on their back. This will be difficult and the seated student probably won’t move anywhere.
• Then, ask the seated student to sit cross-legged on the skateboard (or sit any way that gets their feet off the floor).
• Ask the second student to try again to move the seated student. In this situation, it’s very easy – the wheels on the skateboard greatly reduce the friction. Rolling is easier than dragging/sliding.

Activity 1: Friction and Gravity

• Set one of the smooth car tracks down flat on the desk and place a toy car on top of the track.
• Ask students which forces are acting on the car (gravity and friction).
  • Are the forces balanced or unbalanced?
• Lift one end of the track and the toy car quickly rolls down the track and off the desk.
  • The same forces were acting on the car – gravity and friction – but when the force of gravity became stronger than the force of static friction, the car started to move down the track. At that point, the forces became unbalanced.
• Students will work with a partner to test 2 different tracks (smooth and bumpy) with two different objects (toy car and brick) to determine which track + object has the greatest and least static friction. 

Activity 2: Magnetism

• Hand out a magnet maze per pair, plus one or two magnetic balls and a fridge magnet.
• Ask the students to use their fridge magnet to move the magnetic ball through the maze without touching it.
• Then you can ask them to put one magnet inside the maze and use the second magnet to push and pull the magnet through the maze. 

You can also give the students a pile of paper clips and get them to test how many paper clips the magnet can hold in a vertical line (without hooking the paper clips together).

Activity 3: Static Electricity 

• Give each student one balloon and a empty pop can per each pair.
• Ask the students to "charge" the balloon by rubbing it on their hair.
• Challenge them to move the empty can with their charged balloon without touching the two objects. They can even try a tug of war with their partner.

Activity 4: Buoyancy

• Provide students with the materials to make their own mini-sailboat.
• Show students how to make their sailboat.
• Give each student a straw. They will blow through their straws to create the wind to move their sailboats.
• Put about 10 cm of water in the bottom of a plastic bin/bucket. Give them a few minutes to sail their boats.