Introduction to transportation

Friction revisited

The following video (3:44) discusses some of the factors involved in choosing tyres for Formula 1 car racing.

If increased surface area increases grip, what is the ideal type of tyre for achieving maximum speed?

Newton's three laws of motion

Newton's three laws of motion are explained in the following video (3:32). These laws were first stated by Isaac Newton in 1687. The three laws may be summarised as follows:

1. Every object in a state of uniform motion will remain in that state of motion unless an external force acts on it.  This is also know as inertia.
2. Force equals mass times acceleration (F=ma)
3. For every action there is an equal and opposite reaction.

Hovercrafts

Rocket sled

This interactive rocket sled simulation allows you to change certain variables in real time and see the results.

(https://www.physicsclassroom.com/Physics-Interactives/Newtons-Laws/Rocket-Sledder/Rocket-Sledder-Interactive)

Boats, submarines and buoyancy

Buoyancy is the upward force exerted by a fluid (liquid or gas) that opposes the weight of a partially or fully immersed object. Density is a measure of mass per unit volume.

This video (3:19) shows a simple experiment involving density and buoyancy.

Archimedes principle

This TED-Ed video (4:42) is an animated depiction of Archimedes and his pioneering work with buoyancy.

Submarines

The following video (2:33) explains how submarines work using air to change their buoyancy.

Velocity and acceleration

This video (2:02) explains how acceleration is the rate at which velocity changes over time. It also features some examples of how to use mathematics to calculate the average acceleration.

Conservation of energy

The law of conservation of energy states that energy can neither be created nor destroyed - only converted from one form of energy to another. The following video (1:36) demonstrates this with vivid examples of kinetic and potential energy.

Kinetic energy

Kinetic energy is the energy that an object has because of its motion. The formula for kinetic energy is as follows where 'KE' is Kinetic energy, 'm' is mass and 'v' is velocity:

Kinetic Energy Calculator

The small 2 after velocity is an exponent. Exponent are numbers that indicates how many times another number (the base) is multiplied by itself. For example, in 3² (read as 3 to the power of 2), the base is 3 and the exponent is 2, so it means 3 times 3. Exponents provide a shorthand way to write large, repeated multiplications and are also known as powers. Be careful not to switch around the base and the power. For example, we just learned that 3² is 9 (i.e., 3 x 3) but 2³ is 2 x 2 x 2 = 8.

We will learn more about exponents in SILO 6.3 'Nanotechnology'.

Gears and ratios

Gears are a common way to utilise mechanical advantage in transportation. What are some forms of transportation that you can think of that use gears? 

The following video (2:02) shows how to make simple gears using candy and paper plates.

A good way to visualise gear rations is to image you are wrapping a tape measure around each gear. If the smaller gear is half the size the larger gear, the tape measure could wrap around small gear twice as many times as it does the large gear. An example of this can be seen below: let’s say the perimeter of the large gear is 12 cm, measured with the measuring tape. The perimeter of the small gear is 6cm, which means that if we were to wrap the 12 cm from the large gear around the small gear, it would fit around the object twice.

Torque

Torque can be defined as rotational force. The following video (2:10) explains torque and uses some familiar examples with bicycles.

Ratios

Ratios are comparisons. The following scenario involves a ratio of 1:7.

There were 24,000 people at a concert. For every 7 adults there was 1 child. How many children were at the concert?

Power to weight ratio

The ratio between power and weight is a common consideration when dealing with the performance of an engines and motors. This principle can even be seen in humans when competing in competitions such as Ninja Warrior. The following video (3:13) discusses the power to weight ratio in terms of cycling.

Cars and motorcycles

Cars and motorcycles usually have internal combustion engines or electric motors. The main difference between cars and motorcycles relates to the number of wheels. Most cars have four wheels and most motorcycles have two wheels but there are many exceptions to this. Cars will often need to have a differential so that the wheels can moves at different speeds while cornering. The section after this one explains more about differentials.

Project-based learning: Part 1 of 3 Build your own sail car

• The first part of this challenge is to build a chassis for your vehicle using corflute which is corrugated plastic board.
  
• Bamboo skewers make excellent axles as they fit neatly inside the corflute.
• Plastic or wooden cotton spools make excellent wheels. You can stop the wheels from falling off using masking tape or Blu Tack. If the tape or Blu Tack is obstructing the motion of the wheels you can make small round washers out of cardboard with a hole punched in the centre.
• A sail can be added using thick paper on another bamboo skewer. Another cotton spool and tape and/or Blue Tack can help secure it to the chassis.
• Test the sails cars in the classroom using a large fan or take the sails cars outside to try catching the wind. The picture below doesn't show the movement but this sail car was moving quickly as the wind was very gusty. 
• Remember to use the design cycle throughout this challenge. The changes which you make could also be described as modifications.

Project-based learning: Part 2 of 3 Convert your sail car into an electric car using electronic kits

This challenge is an opportunity to improvise. Improvisation can occur in any situation which involves spontaneity, or creative approaches. Although the electric vehicle will need to be stable and durable, some of the early design work might involve improvisation as part of the design cycle. An example of this is devising temporary supports to hold the motor in place during initial testing.

Project-based learning: Part 3 of 3 Convert your sail car into an electric car using electrical components

Two motors

Six volts connected to one motor

Differentials

This video (5:18) is more advanced than Year 4 children would normally encounter but the main points are that wheels turn at different speeds when cornering and that gears are one way to enable this. Students will also explore how wheels on a non-fixed axle such as on a pram or billy cart are free to turn at different rates.

Camshafts

The following video (6:03) demonstrates some cams and followers using common materials such as cardboard and pencils.

This screenshot from the same video shows some different types of cams, namely, eccentric, egg, snail, elipse and hex.

Air travel and lift

Planes, helicopters and gliders are some of the more common types of air travel. The following video (10:09) explains the force of lift and then gives instruction about how to make your own wing out of paper.

Make your own wing out of paper

As you can see in this screenshot, a hair dryer or fan is required to test it out. The presenter makes reference to Bernoulli's principle. As is states in the Wikipedia article about Bernoulli's principle, "While the equal-time explanation is false, it is not the Bernoulli principle that is false, because this principle is well established; Bernoulli's equation is used correctly in common mathematical treatments of aerodynamic lift".

This next video (3:00) explains why the wind blows which is an important consideration for weather patterns and air travel.

Air travel and the Earth's rotation

The following video (3:15) explains the effect of the Earth's rotation on air travel.

Air pressure experiments

The following video (6:44) contains some air pressure experiments using common materials such as plastic bottles.and paper.

This next video (10:18) is about straws and it explains that suction is really a difference in pressure. It also makes the point that "Nothing sucks in science".

Have you ever noticed how having only one window open while a car is moving can give you sore ears? What do you think might be happening here? The reasons for this phenomenon are explained in the following video (1:30) titled What is wind buffeting and why does it happen?

Hydraulics

Pascal's principle states that the pressure applied to any part of an enclosed liquid will be transmitted equally in all directions through the liquid. The following screenshot is from a video (3:22) about the application of Pascal's law in hydraulics. It shows the formula for comparing both sides of a hydraulic jack.

 

Relative motion

The following video (6:26) on relative motion is an important introduction to the idea that everything is in constant motion. Related terms include 'frame of reference'.

Moderated self-assessment

Discussions with students around the key components of conceptual topics and how they fit together can generate insights into student achievement.

We welcome your feedback and suggestions

The chief investigator for The SILO Project is Associate Professor Brendan Jacobs, Head of Department STEM Education, University of New England. The SILO Project thrives on incremental improvement so constructive feedback is greatly appreciated. Please contact Brendan via email at bjacobs7@une.edu.au to share your thoughts and recommendations.

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

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