A Physics Class

Miss Rose taught physics in a London school Last week she was explaining to one of her classes about sound,and she decided to test them to see how successful she had been in her work,she said to them,"Now,I have a sister in Washington",If I was calling her on the telephone,and at the same time you were 20 metres away,and listened to me from the other side of the street ,who could hear what I said earlier my sister or you ,and why?The cleverest boy at once anserede,"Your sister,Miss Rose,because electricity travels faster than sound waves."That’s very good"Miss Rose answered,But then one of the girls put up her hand,and Miss Rose said,"Yes,Betty""I don’t agree"Betty said."Your sister would hear you earlier because ,when it’s eleven o’clock here,it’s only six o’clock in Washington"

The Impact of Nature, The Teaching and Learning of Elementary Lessons in Students 9-11 Years Old (Case Study: Shiraz Elementary Schools)

In today’s world some changes have been occurred in human lifestyle,these changes,along with the advantages,have led to a series of disadvantages including their disconnection with the nature.One of the most important areas to re-establish the relationship is the school.The presence of nature at schools,and holding some classes in nature,in addition to meeting the special needs of children causes their separation from those small and boring classes as well as their interest in courses.This study aimed to investigate the role of nature in children’s learning.For this purpose,third,fourth and fifth grade classes of 3 schools were held outside the school environment and in the nature in 5 courses.The study is a combinational research and field,indirect observation and library data collection methods were applied,where in the indirect observation,two types of questionnaires were prepared related to the students and teachers and were randomly distributed among 580 students and 50 elementary school teachers.Test reliability was assessed using Cronbach’s alpha and it was obtained to be 0.890.The results of this study indicate that the physical place as one of the factors in children’s learning has the maximum impact on teaching and learning of children.At the end of the study and by investigating the existing factors in the environment we understood that the expansion of the nature and natural light of it causes the students’interest in lessons in nature.

Post-exercise heart rate variability recovery after 800-m endurance run load among Cameroonian adolescent's males

The 800-m(m)run is part of Physical Education classes in Cameroon,after which arrhythmias may occur during recovery.Hence,this study aimed at determining relationship between 800-m run loads on cardiac autonomic recovery among school adolescents.Forty-two male adolescents(aged[17-1]years)performed 800-m.Post-exercise heart rate variability(HRV)was recorded during 5-min(min)(HRV5-min)and 15-min(HRV15-min)in time:Standard deviation of normal to normal(SDNN);Root mean square of successive differences(RMSSD)and frequency domain(LH:Low frequency,HF:High frequency,TP:Total power).Rating of Perceived Exertion(RPE)and blood lactate concentration(BLa)were measured after exercise.In HRV5-min,RPE was associated with SDNN(r=-0.44,p<0.01)and RMSSD(r=-0.38,p<0.05).BLa was correlated with SDNN(r=-0.38,p<0.05)and RMSSD(r=-0.56,p<0.001)in the time-domain,LF(r=-0.64,p<0.001),HF(r=-0.58,p<0.001)and TP(r=-0.61,p<0.001)in frequencydomain.Moreover,RPE was correlated with LF(r=-0.44,p<0.01),TP(r=-0.49,p<0.01)while exercise duration with HF(r=-0.38,p<0.05).In HRV15-min,BLa was correlated with RMSSD(r=-0.53,p<0.001)and SDNN(r=-0.68,p<0.001).RPE was negatively correlated SDNN(r=-0.53,p<0.01)and RMSSD(r=-0.44,p<0.01).BLa was associated with HF(r=-0.55,p<0.001),TP(r=-0.50,p<0.01)and RPE with LF(r=-0.51,p<0.01),HF(r=-0.50,p<0.01),TP(r=-0.49,p<0.01).In addition,exercise duration was negatively linked to HF(r=-0.36,p<0.05).This study outlined that in untrained adolescents an increase of 800-m loads is associated with a slow vagal indexes of HRV during the recovery.