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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

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
I'm not good at math so would you help me
what is the problem that i will help you to self with?
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Tegnologie graad 7. OpenStax CNX. Sep 10, 2009 Download for free at http://cnx.org/content/col11031/1.1
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