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Technology

Grade 7

Transport

Module 2

Transport

For the teacher :

This unit can be done in groups.

Background

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]

Requirements:

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

Method:

  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.

Requirements:

  • 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.

Method:

  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.

Observation?

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

Conclusion:

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.

Assessment

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

explain and give four Example hyperbolic function
Lukman Reply
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
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Rofiqul
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Shirley Reply
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Abdullahi
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Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
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Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
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Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
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Seidu
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Opoku
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Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
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Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
Alfred Reply
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
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
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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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