☰ Contents · Natural science

Physical phenomena; motion and force

Lessons 51–52 · 2 lessons · Y.V. Malikova, S.V. Kosyanenko. Natural Science Grade 4, Part 1. Novda Edutainment, Tashkent, 2023; S.V. Kosyanenko, Y.V. Malikova, O.E. Tigay. Natural Science Grade 4, Part 2. Novda Edutainment, Tashkent, 2023
51

Physical phenomena

Textbook: Part 2, pp. 78–81
GoalTell apart physical phenomena (mechanical, thermal, light, sound, electrical, magnetic) and know examples.
New words
phenomenon · hodisasound · tovushlight · yorug‘likmagnet · magnit
Explanation

Phenomena in which the substance itself does not change, only its state or place, are called physical phenomena. A mechanical phenomenon is the motion of a body (a ball rolling, a car driving). Thermal phenomena are warming, cooling, ice melting, water boiling. Light phenomena are sunrise, shadows, a rainbow. Sound phenomena: a vibrating string makes a sound. Electrical phenomena: a lamp lighting, lightning. A magnetic phenomenon: a magnet pulls iron. Melting ice is physical: ice and water are the same substance — water. Boiling water and electricity are dangerous: do not touch them without an adult, and never put anything into a socket.

Worked examples
Ice melting is a thermal phenomenon; a shadow forming is a light phenomenon.
Class activity

Press a ruler on the table edge, pluck its free end and let go: a sound is made. Change the ruler’s length and hear how the sound changes.

Practice
1
Give an example of a mechanical phenomenon.
2
What kind of phenomenon is ice melting?
3
Why must nothing be put into a socket?