The underlying force pumping the water sprinkler

I bet most of you might know about a water/lawn sprinkler. For those who do not know, a water sprinkler is used to spray water in the lawns and/or used by farmers to irrigate the crop fields.


Image: A water sprinkler

The working principle of water sprinklers

Let us first start with a fun and an interesting science project in order to understand the mechanism by which water is sprayed throgh a sprinkler. For this we need the following materials:

a) A plastic straw

b) A wooden skewer

c) A masking tape, and

d) A container filled with water

The sprinkler will look something as shown below

Image credit:

The detailed steps of the project can be found at the following website links:

teachbesideme and kidsfunscience

The simple principle behind the working of water sprinkler above is that as we spin the straw it forces the water inside to spin. As the spinning continues, any object on it appears to feel a centrifugal force pushing it outward. When we move up the the straw, the water in the straw moves outwards  and is pumped upwards. If you spin the straw fast enough then water will exit the straw and fly outwards. Many pumps use the same principle, they consist of a fluid inlet in the middle, and then an impeller spins the fluid, and centrifugal force pushes the fluid outwards and out through an outlet.

The materials used in sprinkler are usually different from the above project. The best selling models of water sprinklers are made from very inexpensive materials as aluminum tubing, plastic, and rubber.


Can you crack the code?

crack a code

What are rounded bumps and why are they important to plants?

Do you know what plants need to grow besides soil, water, and sunlight?

The essential element required for the survival of plants is nitrogen (N). Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy. The problem is, although the Earth’s atmosphere is made up of 78% nitrogen, the form of nitrogen found in the atmosphere cannot be used by plants.

How do plants get their nitrogen?

Either through nitrogen deposits in the soil, or through a friendly relationship with nitrogen-fixing bacteria.


Figure 1. Description of nitrogen cycle (

Let us learn through this simple and easy science experiment:

a) What are the nitrogen-fixing bacteria?

b) Why are they so important for some plants survival?

Materials needed:


clover seeds/plants

quart liter plastic bucket

tap water

paper towels

magnifying lens/simple microscope

Ready to start??


Step 1. Take out the clover plants from their roots using a trowel.


Step 2. Dip the roots of the clover plants in a bucket of water in order to remove the dirt from the roots.

Step 3. Using a paper towel blot the plants to absorb any excess water.



Step 4. Observe the roots using a magnifying lens. You can also observe the nodules under a microscope by cutting a section of the root and placing it on a microscope slide.

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What do you observe?


These tiny potatoes like structures are called as nodules. The nodules are separate and appear at different places along the roots and most of them are clumped together.

What are the functions of these nodules on roots?


Nitrogen gas makes up 78% of the earth’s atmosphere, but plants cannot use this form of nitrogen.

Then how plants take up the nitrogen for their growth and survival???

a) Here comes the role of bacteria called nitrogen-fixing bacteria that change nitrogen gas into nitrogen compounds that plants can use. Some nitrogen-fixing bacteria live in the soil, while others live on the roots of the plants as clover.

b) The bacteria enter the root hairs of the plant, and as they multiply a nodule forms. The bacteria and clover help each other.

c) The bacteria “fix” nitrogen gas so that the plant can use it, and the plant provides food for the bacteria. This process is known as symbiosis: when two organisms living together, are mutually benefitted.

Science Fair Ideas: You can observe the content of the nodules through a microscope by cutting the nodule into halves and displaying the photographs.



Operating system – the brain behind your electronic devices

Similar to the brain which controls and send signals for performing various tasks and regulates the actions in most living beings the Operating system takes care of managing the hardware and software running in our laptops, mobiles, microwaves, digital thermometer and most most other modern day electronic devices which have some any sort of event based functions and/or digital displays. This comparison of OS with the brain is only to stress upon its importance as the brains are a lot more complex systems and still being researched upon.

When you are playing a game on your mobile, watching a movie in Netflix on your television or simply running on a treadmill with digital display there are operating systems which tells these devices/machines what to do by controlling the system resources like processors, memory, camera, displays etc. The main function of any operating system is to manage the hardware and software of the device.


Some everyday devices which have their work on an Operating system

Micro-controller/ Microprocessors Mobile OS Computer OS
Description Microprocessors are usually computers on a single integrated circuit.

Micro-controllers usually contains microprocessors and have additional RAM, ROM and other peripherals all embedded on a single chip

A mobile OS is specifically designed to run on mobile devices such as mobile phones, smartphones, PDAs, tablet computers and other handheld devices. Android, iOS and Symbian OS etc. are some popular ones.

The mobile OS provide platform on top of which other programs and apps can run on mobile devices.

Computer OS usually comes with any desktop/laptop that you buy. The three most common operating systems for personal computers are Microsoft Windows, Mac OS X, and Linux.

These operating system sits between applications and hardware, managing how applications access hardware and software resources.

Devices Digital Thermometer, The ABS or temperature control on your car, the sensor on your security cameras Mobile phones, handheld scanners, handheld payment processors, iPad, tablets Laptop, desktop, application and database servers

To see how an OS differs from another the best thing in my opinion is to use a Raspberry Pi and install the various suggested OS and try them out this summer. Let us know if you need any help or have query regarding running an OS on your Pi.

You can buy a Raspberry Pi or use any of its various alternatives and be prepared to spend your nights playing with these.



Reading with codes

Do you love to read and write secret codes? Let us solve the clue attached.

Old MacDonald Had a Code-page-001


Achieving higher magnification using a compound microscope

A compound microscope is an optical instrument with more than one lens and its own light source. Compound microscope is used to obtain high magnification. It is an extension of the magnifying glass which are used to see very small things. The magnifying power of a simple lens is very limited. It is difficult to get a magnification better than a few times without using a highly curved lens with a high refractive index. This kind of lens will have a lot of aberrations that one can not see the image clearly. Therefore, we used two or more lenses which builds up the compound microscope.

Figure 1. Diagram showing light traveling through the compound microscope

Principle of compound microscope

A compound microscope works on the principle that when a tiny object to be magnified is placed just beyond the focus of its objective lens, a virtual, inverted and highly magnified image of the object is formed at the least distance of distinct vision from the eye held close to the eye piece.

Construction of compound microscope
A compound microscope consists of two convex lenses: an objective lens O of small aperture and an eye piece E of large aperture. The lens which is placed towards the object is called objective lens, while the lens which is towards our eye is called eye piece. These two convex lenses i.e. the objective and the eye piece have short focal length and are fitted at the free ends of two sliding tubes at a suitable distance from each other. Although the focal length of both the objective lens and eye piece is short, but the focal length of the objective lens O is a little shorter than that of the eye piece E.
The reason for using the eye piece of large focal length and large aperture in a compound microscope is, so that it may receive more light rays from the object to be magnified and form a bright image.

Figure 2. Parts of a compound microscope

There are two main parts of compound microscope:

  1. Structural/Mechanical components
  2. Optical components

parts of compound microscope


Working of a compound microscope

Figure 3. Ray diagram of a compound microscope

The ray diagram to show the working of compound microscope is shown in figure. A tiny object AB to be magnified is placed in front of the objective lens just beyond its principal focus fo’. In this case, the objective lens O of the compound microscope forms a real, inverted and enlarged image A’B’ of the object.

Now A’B’ acts as an object for the eye piece E, whose position is adjusted so that A’B’ lies between optical centre C2 and the focus fe’ of eye piece. Now the eye piece forms a final virtual, inverted and highly magnified image A”B”. this final image A”B” is seen by our eye hold close to eye piece, after adjusting the final image A”B” at the least distance of distinct vision of 25 cm from the eye.


Are there any differences between simple microscope and compound microscope? Can you tell them?

Some popular microscopes below $100 are:

Compound Microscope AmScope Microscope Beginner Microscope

Riddle for the day


Addition Word Problems

Addition Word Problems

Math Anagrams


Quiz of the day 1

quiz 1

What is a light microsope?

A microscope is an instrument used to produce enlarged images of small objects. The most common kind of microscope is an optical microscope, which uses lenses to form images from visible light. The optical microscope has been a standard tool in life science as well as material science for more than one and a half centuries now. The optical microscopes are of two main types:

a) Simple Microscope                                      b) Compound Microscope

labeledmicroscopeimageFigure 1. Parts of a simple microscope

The simple microscope is generally considered to be the first microscope. It was created in the 17th century by Antony van Leeuwenhoek, who combined a convex lens with a holder for specimens, magnifying between 200 and 300 times.

The structure of a simple microscope is very simple. It has a body, a stage made of thick glass for placing slides, two clips to fix the slides, a handle, an eyepiece placed with the handle and a mirror. There is an adjustment knob by which the eye piece may be moved upward and downward. The entire body stands on the base or foot.

How to handle the simple microscope?

At first the slide is to fix on the stage with the help of clips. The light should be focused on the slide by moving the mirror. Then keeping the eye in the eye piece the adjustment knob should move in such a way that the eyepiece comes to a position from where the object on the stage can be seen most clearly. At this position, keeping the eye in the eyepiece, the specimen is to be observed carefully, or if required be dissected with the help of forceps or needle whichever is convenient.

Principle: A simple microscope works on the principle that when a tiny object is placed within its focus, a virtual, erect and magnified image of the object is formed at the least distance of distinct vision from the eye held close to the lens.


Figure 2. Working of a simple microscope When an object is placed between the principle focus and the optical centre of a convex lens a virtual, erect and magnified image is formed. The ray diagram is given here explains how an object looks enlarged when viewed through a bi-convex lens. Observe that the object and the image are on the same side of the lens. Image is formed at the least distance of distinct vision from the eye i.e., the distance from the object is approximately equals to 25 cm.

Magnification of Simple Microscope
The magnifying power of a simple microscope is given by:
m    =     1    +   D/f

D = least distance of distinct vision
F = focal length of the convex lens

The focal length of the convex lens should be small because smaller the focal length of the lens, greater will be its magnifying power. Also, the maximum magnification of a simple microscope is about 10, which means that the object will appear 10 times larger by using the simple microscope of maximum magnification.

Limitations of using a light microscope: Visible light restricts the amount of resolution achieved with a light microscope. Magnification may range from 500x to 1500x. In general, light microscopes require specimens to be thin, small and transparent for optimum viewing. The diffraction limits the resolution to approximately 0.2 µm.

Uses of a simple microscope:

  1. Besides medicine and biology, geologists use microscopes to examine rocks and minerals and materials scientists use them to study plastics and polymers. Engineers use microscopes to study surface properties and structures of metals.
  2. Forensic science is the study of crime scenes for the purpose of presenting evidence in courts of law. Evidence such as dust, glass, body fluids, hair, inks, and microorganisms can be analyzed using microscopy.
  3. Microscopes are also used in the service, manufacturing, and pharmaceutical industries to ensure the safety and quality of products. Scientists in these industries examine their products microscopically to identify any flaws or contaminants.





microscope parts label

  1. Label the parts of a simple microscope in the figure above.

2. A light microscope is also referred to as a?

a) Electron microscope

b) Compound microscope

c) Scanning problem microscope

d) X-ray

3. On the microscope stage, what is used to hold the glass slide in place and prevent it from moving?

a) Stage clip

b) Stage

c) Fine adjustment knob

d)    Condenser

4. Ocular lens

a) Is used to regulate the amount of light on the specimen

b) You look through to see the specimen

c)  Projects light upwards through the diaphragm, the specimen, and the lenses

5. What happens when light passes through a condenser lens?

6. What does the objective lens do?

7. What is the maximum magnification of a light microscope?

8. What is the maximum resolution of a light microscope?

9. What are the advantages of a light microscope?





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