1. susie wondered if the height of a hole punched in the side of a quart-size milk carton would affect how far from the container a liquid would spurt when the carton was full of the liquid. she used 4 identical cartons and punched the same size hole in each. the hole was placed at a different height on one side of each of the containers. the height of the holes varied in increments of 5 cm, ranging from 5-20 cm from the base of the carton. she put her finger over the holes and filled the cartons to a height of 25 cm with a liquid. when each carton was filled the proper level, she placed it in the sink and removed her finger. susie measured how far away from the carton’s base the liquid had squirted when it hit the bottom of the sink.

hypothesis:
independent variable:
dependent variable:
constant (at least one):
control:
number of groups:
number of trials per group:

A scientific experiment is performed to test the hypothesis which is the predicted idea about the natural phenomenon based on the previous research.

The experimental design must contain three types of variables: the variable which can be manipulated  (independent variable). the variable which is to be tested (dependent variable) and the variable which is kept constant throughout the experiment (constant variable).

The experimental sample is divided into two groups: the experimental group which includes the factor to be studied and the control group which lack the factor to be studied.

In the given question,

1. Hypothesis:  liquid spurt when falls form a height.

2. Independent Variable:  Height of hole which gets changed

3. Dependent Variable:  Range of squirt which is to be tested

4. Constant (at least one):the volume of filled liquid is kept constant

5. Control: 4 identical cartons which are punched with a hole of the same size.

6. A number of groups:  two (control and experimental)

7. Number of trials per group: four

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.