Session 3: Challenge : How to create a opposite force to gravity

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Objective 1: How to generate a force that is opposite to gravity

Objective 2: Increasing friction force not in the air but in water

 

Explanation

The objective here is to develop a more playful approach. In order to propose to the students to create  a force that is opposite to gravity, they will used this friction force that we tried to minimized in the previous session

Material

• Container full of water
• Play dough with density higher than water (Sinking play dough)
• Chronometer (optional)
• Kitchen Scale

Maximum duration

30 minutes

Main question to be asked

Challenge: Give to each group a play dough ball. They should make it sink as slow as possible

Main activities

1. Ask them to weigh a ball of play  dough of 20g for each group.Ask them to make it sink; is it possible to time the process?
2. Ask them to make the play dough float
3. Challenge them to make a contest between the different groups of student and make the play dough sink as slowly as possible. Give them stop watchs to compare times.

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Conclusion/Plenary

In this challenge, the winning group will be the one that manages to increase friction force by increasing the surface of the play dough.  They have to play on the opposite principle that they experimented in session 2. By increasing the drag forces, increasing the area of the play dough they reduce the effect of the gravity and the play dough is slowed down in its movement.