GRADE SIX SCIENCE
Hello Boys and Girls, Have you been working very hard during the past week? Have you been doing lots of revision? Ensure that you revise well and ask questions about anything you do not understand. Do not just learn facts but understand them and think through them.
Last week we looked at pulleys. Do you remember what we found out? Check yourself.
i. What is a pulley? ii. Describe pulleys. iii. Name at least two places where pulleys can be found. iv. Draw a fixed pulley. Draw a moveable pulley.
Use the words following to try out making a wordsearch exercise. machines, simple, lever, pulley, flagpole, load, effort, fulcrum, pivot
This week we will investigate another simple machine; the wheel and axle.
The wheel is a great invention! We can hardly do without it. The wheel by itself, however, is not a simple machine. A wheel by itself is simply a roller. Maybe the idea of a wheel came about from rolling logs along the ground many years ago.
The wheel is part of a simple machine called the wheel and axle. The axle is a smaller wheel or cylinder fitted tightly in the centre of the larger wheel. The axel works along with the larger wheel. Wheels and axes are found everywhere.
The wheel and axle helps us to push or pull very heavy objects with much more ease. Imagine how hard it would be to push a cart of groceries around a supermarket if the cart had no wheels.
Every time you turn a doorknob you are using a wheel and axle. If there were no knob on the rod that goes through a door, it would be difficult to open the door. The knob makes it easier to work the latch.
The knob is a wheel. The rod is an axle. The wheel and axle work together to open the door. A wheel and axle is used in many machines. The wheel and axle helps is to do work in many ways. This simple machine makes it easy to turn things and to move things.
Do you know what a windlass is? If you don’t, please find out before moving on.
A windlass is a kind of wheel and axle. It has a horizontal axle for hauling or hoisting.
Would you like to make your own windlass? Your windlass will help you to see how a wheel and axle moves things.
You will need nails, rope/string, screw eyes (curtain rods screw eyes), a small wheel (about 15cm in diameter), a large wheel (about 30cm in diameter), a base made of wood (about 30cm wide by 60cm long), a wood rod (about 60cm- a broom or mop stick will do) and two side blocks. Look carefully at the picture.
Can you find any wheel and axle on the bicycle below? Look carefully and discuss with a friend. What kind of machine is this?
Let’s look at another picture.
Discuss the how the wheel and axle here works.
FOR YOU TO DO:
Name at least five places (especially around your home) where there are wheels and axes.
Until next week, goodbye, Boys and Girls!