How would seasons on earth be different if the earth was not tilted on its axis

If the Earth's axis were 'straight' ... pefectly perpendicular to the ecliptic
plane ... then:

-- Day and night would be the same length ... every day of the year,
everywhere on Earth !

-- There wouldn't be any seasons, anywhere.  There might still be some
'weather' ... cloudy days, sunny days, occasional rain, wind etc.  But
there would be no average change during the year.  No hot months or
cold months.  In any one place, the weather would always be generally
the same, every day, all year.  Everywhere all around the equator would be
generally the hottest on Earth, and the local climates would generally get
cooler as you moved away from the equator and toward the poles.

The sample with the lowest specific heat capacity will have the greatest temperature increase. in this case, it would be platinum.

Year  1936,  lehman predicted that the earths 'inner core' is solid. she observed that the seismic signals during her study were bent and did not pass through instead bouncing back. later it was confirmed that the earth's inner core was solid made up of nickel-iron and had a molten outer core.