Good Science Victorian Curriculum Year 7

INVESTIGATIONS
Investigation 8.2
Blowball
KEY SKILL
IDENTIFYING AND MANAGING
RELEVANT RISKS
Brainstorm with a partner to identify three possible
hazards or risks that may be involved in this
investigation. Suggest one way that each hazard
or risk could be reduced.
AIM
To investigate the effects of unbalanced forces on a
ping-pong ball
MATERIALS
• table
• ping-pong ball
• 4 drinking straws
METHOD
1 Gather into groups of four. Each member of the
group takes one straw and kneels at a different side
of the table.
2 Place the ping-pong ball in the centre of the table.
3 Take turns to blow through your straws to move the
ball around the table.
4 Have one group member blow the ball across
the table while the others blow on it in the other
direction.
5 Have one group member blow the ball across the
table while the others blow on it from the sides.
30 min
6 Divide into two pairs, with each pair on a different
side of the table. As a pair, try to blow the ball across
the table and off the side while the other pair does
the same.
7 Record observations in your book. In particular,
detail how different sized forces were able to affect
the motion of the ball.
QUESTIONS
1 At what times were the forces on the ball balanced?
2 Describe what happened to the speed and direction
of the ball when you blew on it as it moved
towards you.
3 What happened when you blew on the ball as it
moved at a right angle to you?
4 Draw a force diagram showing the forces that were
acting on the ball as you blew it away from you.
CONCLUSION
Copy and complete:
‘The results show that: (respond to the aim)’.
Level 1
176 GOOD SCIENCE VICTORIAN CURRICULUM 7