Secondary School (English Medium) (5 to 8) इयत्ता ७ - CBSE Question Bank Solutions for Science

Which of the two changes frequently, weather or climate?

Fill the missing word in the blank spaces in the following statements:

Air moves from a region of __________ pressure to a region of ________ pressure.

Suggest two methods to find out wind direction at a given place.

State two experiences that made you think that air exerts pressure.

You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.

Explain why holes are made in hanging banners and hoardings.

Explain how soil is formed.

Sketch the cross section of soil and label the various layers.

A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?

The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.

The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.

Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.

Suppose the two photographs, shown in Figure 1 and Figure 2, had been taken at an interval of 10 seconds. If a distance of 100 metres is shown by 1 cm in these photographs, calculate the speed of the fastest car.

Figure 1 Vehicles moving in the same direction on a road

Figure 2 Position of vehicles shown in Figure 1 after some time

Wastewater released by houses is called ______.

Explain why it is harmful to discharge untreated sewage into rivers or seas.

Here is a crossword puzzle: Good luck!

Across

3. Liquid waste products

4. Solid waste extracted in sewage treatment

6. A word related to hygiene

8. Waste matter discharged from human body

Down

1. Used water

2. A pipe carrying sewage

5. Micro-organism which causes cholera

7. A chemical to disinfect water

Why do farmers grow many fruits and vegetable crops inside large greenhouses? What are the advantages to the farmers?

Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.

Every object moves with a constant speed.

Distances between two cities are measured in kilometres.