<< Chapter < Page Chapter >> Page >


Grade 7


Module 2


For the teacher :

This unit can be done in groups.


Planes fly at high speeds. They have large engines that let out a powerful source of air that propels the plane through the air. To illustrate quite simply how a plane or a rocket works, you can make a balloon fly.

Activity 1:

How to make a balloon fly

[lo 1.3]


  • A piece of string, about 5 m long.
  • Adhesive tape.
  • A balloon.
  • A drinking straw.
  • A clothes-peg.


  1. Thread the piece of string through the drinking straw.
  2. Fasten the string in two places, e.g. between two chairs so that it stretches over a distance and is stretched tightly.
  3. Stick two pieces of adhesive tape to the drinking straw.
  4. Inflate the balloon and close the opening with a clothes-peg. Stick the balloon to the drinking straw with the two pieces of adhesive tape.
  5. Move the balloon to one end of the string. Let go of the balloon by removing the peg.

What are your observations?

  • The balloon with the string flies at a high speed.
  • The stream of air rushes out at the opening and pushes the balloon forward. It is a reaction to an action, i.e. the movement in one direction (air that is exhausted at the rear end) causes movement in the opposite direction (balloon moves forward).

Background: How does the engine of a plane or a rocket work?

The large blades of the turbine draw air in at the front and compress it. Fuel is burned in the air and this causes the air to heat up. Following that, the warm air is exhausted at the rear end of the engine. It causes the plane/rocket to move forward at a high speed. This reaction has been known to man for almost 2 000 years, but it was only used in an engine for the first time in 1930.

The thrust exerted by moving air or water can cause objects to perform work or can even generate electricity. Air under pressure and a liquid like water can therefore be used to make things work.

The purpose of a rocket is to get a satellite or astronauts into outer space. To achieve that, gravity, i.e. the force that attracts everything to the earth, must be overcome. If the engines of a rocket are not strong, gravity will win and will pull the rocket back to earth. If the force applied by the rocket and the gravity with which the earth attracts the rocket are equal, the rocket will continue to orbit the earth.

Activity 2:

To launch your own rocket

[lo 1.3]

For the teacher:

It is better to do this experiment outside.


  • 5 ml bicarbonate of soda.
  • One sheet of paper towelling.
  • 125 ml water.
  • 125 ml vinegar.
  • A 2ℓ plastic cool drink bottle.
  • A cork that fits tightly in the mouth of the bottle with some trimming at the top.


  1. Put 5 ml of bicarbonate of soda exactly in the centre of the sheet of paper towelling. Roll the sheet up and fold the ends in so that the bicarbonate of soda is tucked safely inside.
  2. Take the 2ℓ plastic bottle and put 125 ml water and 125 ml vinegar in the bottle.
  3. Decorate the cork with a ribbon.
  4. Put the paper towel inside the bottle and put the cork on the bottle immediately so that it fits tightly, but not too tightly.
  5. Stand about 3 m away and see what happens.


The cork is blown into the air like a rocket being launched..


A chemical reaction between the vinegar (representing the liquid oxygen) and the bicarbonate of soda (representing the fuel) produces the gas, carbon dioxide. The air forming in the bottle exerts pressure against the cork and causes the cork to shoot up into the air. During the launching of a real rocket, the gas is exhausted from the rocket, causing it to move forward/upward.

NB: It is dangerous to play with chemicals, and irresponsible handling of these substances could lead to serious injuries as a result of explosions or burning. Therefore, be very careful. Wear goggles to protect your eyes and only work under supervision of your educator.


Learning outcomes(LOs)
LO 1
Technological processes and skillsThe learner will be able to apply technological processes and skills ethically and responsibly using appropriate information and communication technology.
Assessment standards(ASs)
We know this when the learner:
Investigates :1.3 investigates the background context, the nature of the need, the environmental situation, and the people concerned when given a problem, need or opportunity set in a local context;

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Tegnologie graad 7. OpenStax CNX. Sep 10, 2009 Download for free at http://cnx.org/content/col11031/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Tegnologie graad 7' conversation and receive update notifications?