|
 |
|
|
 |
 |
 |
|
You will need Acrobat
Reader installed to open the activity sheets.
You will also need the latest version of the flash player to be able to play swf files.
|
· That when an object is submerged in water, the water provides an upward force (upthrust) on it
Children will demonstrate this by completing the task on page 3 successfully.
· To represent the direction of forces by arrows
Children will demonstrate this by completing the task on page 4 successfully.
· That weight is a force and is measured in newtons
Children will demonstrate this by completing the task on page 4 successfully.
|
 |
|
| |
|
|
|
 |
Science:
QCA unit 6E -Forces in action
· That when objects are pushed or pulled, an opposing push or pull can be felt
· How to measure forces and identify the direction in which they act
ICT:
· Web links for further research on how hot air balloons and submarines work
|
| |
|
 |
Introducing the activity
· Display page 1 through a data projector or on an OHT. Ask the children if they have any ideas about how these things work. Explore ideas such as the hot air burner on the balloon pushing the balloon up. Relate ideas expressed to previous work on forces.
Leading the main activity
· Display page 2 through a data projector or on an OHT. Print off copies for the children. Read or ask the children to read the facts aloud. Which reason do they think may be the correct one?
· Display page 3 through a data projector or on an OHT. Print off copies for the children. Revisit the idea of upthrust. Generate discussion by describing how it feels when you try to submerge a beach ball in the swimming pool and how you can feel the water pushing it up as you try to push it down. Discuss how the submarine can change weight by taking on water or by emptying the water tanks. Ask the children to work in pairs to decide which word should fit in which box.
· Display page 4 through a data projector or on an OHT. Print off copies for the children. Discuss how the hot air balloon works. Is the balloon heater on all the time? Why not? What is the purpose of sandbags? Ask the children to draw arrows on the diagram to show in which direction the forces are acting.
Q. How many children can the hot air balloon lift?
In order for the balloon to rise the upthrust needs to be greater than the weight of the balloon plus passengers
Calculation:
Upthrust = 20,000 newtons
Weight of balloon = 17 000 newtons
Therefore the difference in weight = 20, 000 - 17,000 = 3000 newtons
Each child weighs 500 newtons so 3000/500 = 6 children
However, if 6 children are added then upthrust is equal to weight of balloon plus children so the balloon will not rise
If 5 children are added then upthrust =20,000 newtons and balloon with children = 19,500 newtons
In this case the upthrust is more than the weight of the balloon plus children so the balloon will rise
A. Number of children that can be lifted = 5
|
| |
|
 |
|
E-balloon
How the balloon works
BBC News
Details of balloon flight record
How Stuff Works
How hot air balloons work
Wikipedia - Hot air balloon
All about how hot air balloons work
CNN
Sonar and surfacing: how a submarine works
How Stuff Works
How Submarines Work (animation)
National Geographic
Evolution of subs - photos and facts
|
| |
|
 |
Write
your online review to share your feedback and classroom tips with other teachers. How well does it work, how engaging is it, how did you use it, and how could it be improved?
|
| |
 |
|
|
| |
|
| |
|
| |
